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Using a relative path for the MasterPageFile throws an exception #26

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Using a relative path for the MasterPageFile throws an exception #26

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djsell
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@djsell djsell commented Nov 12, 2010

bug fix for 653192

@djsell
making MasterPageFile handle relative paths
0c91df3 
MasterPageFile should be relative to the file being parsed, not the
request path
luliyi1024 referenced this pull request in luliyi1024/mono Mar 19, 2013
@joncham
Merge pull request Unity-Technologies#26 from Unity-Technologies/mono…
3e98029 
…-bisect

Workaround bad request for generic method during evaluation.
akoeplinger added a commit that referenced this pull request Jun 5, 2017
@akoeplinger
Revert "[marshal] delay dummy string allocation"
d30c17f 
Reverts 5e23a77

It seems to cause a crash during msbuild tests:

```
  xunit -> Microsoft.Build.Engine.UnitTests...
  Stacktrace:

  Native stacktrace:

  	0   mono                                0x0017cad4 mono_handle_native_crash + 308
  	1   mono                                0x001e2b03 sigabrt_signal_handler + 147
  	2   libsystem_platform.dylib            0x920a8deb _sigtramp + 43
  	3   ???                                 0xffffffff 0x0 + 4294967295
  	4   libsystem_c.dylib                   0x940bb27c abort + 155
  	5   mono                                0x0036886d mono_log_write_logfile + 381
  	6   mono                                0x003630d2 structured_log_adapter + 50
  	7   mono                                0x00380d1b monoeg_assertion_message + 107
  	8   mono                                0x0033863d major_scan_object_with_evacuation + 3373
  	9   mono                                0x0033b3d0 drain_gray_stack + 6608
  	10  mono                                0x0032df57 finish_gray_stack + 151
  	11  mono                                0x0032d3c6 major_finish_collection + 118
  	12  mono                                0x00329909 major_do_collection + 169
  	13  mono                                0x003288bd sgen_perform_collection + 605
  	14  mono                                0x0032a90b sgen_gc_collect + 75
  	15  mono                                0x002d5c4d unload_thread_main + 861
  	16  mono                                0x002abb6b start_wrapper + 795
  	17  libsystem_pthread.dylib             0x9ae6d5fb _pthread_body + 144
  	18  libsystem_pthread.dylib             0x9ae6d485 _pthread_struct_init + 0
  	19  libsystem_pthread.dylib             0x9ae72cf2 thread_start + 34

  Debug info from gdb:

  (lldb) command source -s 0 '/tmp/mono-gdb-commands.2tso9f'
  Executing commands in '/tmp/mono-gdb-commands.2tso9f'.
  (lldb) process attach --pid 2037
  2017-06-02 13:07:23.000 lldb[2093:282f] Metadata.framework [Error]: couldn't get the client port
  Process 2037 stopped
  * thread #1, name = 'tid_507', queue = 'com.apple.main-thread', stop reason = signal SIGSTOP
      frame #0: 0x923cc7ca libsystem_kernel.dylib`__psynch_cvwait + 10
  libsystem_kernel.dylib`__psynch_cvwait:
  ->  0x923cc7ca <+10>: jae    0x923cc7da                ; <+26>
      0x923cc7cc <+12>: calll  0x923cc7d1                ; <+17>
      0x923cc7d1 <+17>: popl   %edx
      0x923cc7d2 <+18>: movl   0xe0b084f(%edx), %edx

  Executable module set to "/Users/builder/data/lanes/2716/mono-mac-sdk/external/bockbuild/stage/bin/mono".
  Architecture set to: i386-apple-macosx.
  (lldb) thread list
  Process 2037 stopped
  * thread #1: tid = 0x530e96a, 0x923cc7ca libsystem_kernel.dylib`__psynch_cvwait + 10, name = 'tid_507', queue = 'com.apple.main-thread', stop reason = signal SIGSTOP
    thread #2: tid = 0x530e96b, 0x923cc7ca libsystem_kernel.dylib`__psynch_cvwait + 10, name = 'SGen worker'
    thread #3: tid = 0x530e96c, 0x923cc7ca libsystem_kernel.dylib`__psynch_cvwait + 10, name = 'SGen worker'
    thread #4: tid = 0x530e96d, 0x923c7fb6 libsystem_kernel.dylib`semaphore_wait_trap + 10, name = 'Finalizer'
    thread #5: tid = 0x530e96e, 0x923cd992 libsystem_kernel.dylib`kevent64 + 10, queue = 'com.apple.libdispatch-manager'
    thread #6: tid = 0x530ea26, 0x923ccace libsystem_kernel.dylib`__select + 10, name = 'tid_5a03'
    thread #7: tid = 0x530edf1, 0x923cc7ca libsystem_kernel.dylib`__psynch_cvwait + 10, name = 'tid_4007'
    thread #8: tid = 0x530edf2, 0x923cc7ca libsystem_kernel.dylib`__psynch_cvwait + 10, name = 'Threadpool worker'
    thread #9: tid = 0x530edf3, 0x923cc7ca libsystem_kernel.dylib`__psynch_cvwait + 10, name = 'Threadpool worker'
    thread #10: tid = 0x530edf4, 0x923ccff2 libsystem_kernel.dylib`__wait4 + 10, name = 'Domain unloader'
  (lldb) thread backtrace all
  * thread #1, name = 'tid_507', queue = 'com.apple.main-thread', stop reason = signal SIGSTOP
    * frame #0: 0x923cc7ca libsystem_kernel.dylib`__psynch_cvwait + 10
      frame #1: 0x9ae6fd1d libsystem_pthread.dylib`_pthread_cond_wait + 728
      frame #2: 0x9ae71bd9 libsystem_pthread.dylib`pthread_cond_wait$UNIX2003 + 71
      frame #3: 0x00361ea9 mono`mono_os_event_wait_multiple + 505
      frame #4: 0x00361ca5 mono`mono_os_event_wait_one + 53
      frame #5: 0x00376b49 mono`mono_thread_info_wait_one_handle + 41
      frame #6: 0x002d51b5 mono`mono_domain_try_unload + 485
      frame #7: 0x002d4f6a mono`ves_icall_System_AppDomain_InternalUnload + 90
      frame #8: 0x05bf9ee0
      frame #9: 0x018ce01d mscorlib.dll.dylib`System_AppDomain_Unload_System_AppDomain + 45
      frame #10: 0x05bf9d60
      frame #11: 0x05bf9ccc
      frame #12: 0x05bf9d04
      frame #13: 0x05bf9c90
      frame #14: 0x05bf996d
      frame #15: 0x02e7d171
      frame #16: 0x005c26d4
      frame #17: 0x005b6878
      frame #18: 0x005b6b7a
      frame #19: 0x000c38a8 mono`mono_jit_runtime_invoke + 1592
      frame #20: 0x002e43fe mono`do_runtime_invoke + 94
      frame #21: 0x002e7de3 mono`do_exec_main_checked + 147
      frame #22: 0x002e69a5 mono`mono_runtime_run_main_checked + 69
      frame #23: 0x0013b687 mono`mono_jit_exec + 311
      frame #24: 0x0013e2b2 mono`mono_main + 10114
      frame #25: 0x000b22db mono`main + 2011
      frame #26: 0x000b1af5 mono`start + 53
    thread #2, name = 'SGen worker'
      frame #0: 0x923cc7ca libsystem_kernel.dylib`__psynch_cvwait + 10
      frame #1: 0x9ae6fd1d libsystem_pthread.dylib`_pthread_cond_wait + 728
      frame #2: 0x9ae71bd9 libsystem_pthread.dylib`pthread_cond_wait$UNIX2003 + 71
      frame #3: 0x0035f0e9 mono`thread_func + 249
      frame #4: 0x9ae6d5fb libsystem_pthread.dylib`_pthread_body + 144
      frame #5: 0x9ae6d485 libsystem_pthread.dylib`_pthread_start + 130
      frame #6: 0x9ae72cf2 libsystem_pthread.dylib`thread_start + 34
    thread #3, name = 'SGen worker'
      frame #0: 0x923cc7ca libsystem_kernel.dylib`__psynch_cvwait + 10
      frame #1: 0x9ae6fd1d libsystem_pthread.dylib`_pthread_cond_wait + 728
      frame #2: 0x9ae71bd9 libsystem_pthread.dylib`pthread_cond_wait$UNIX2003 + 71
      frame #3: 0x0035f0e9 mono`thread_func + 249
      frame #4: 0x9ae6d5fb libsystem_pthread.dylib`_pthread_body + 144
      frame #5: 0x9ae6d485 libsystem_pthread.dylib`_pthread_start + 130
      frame #6: 0x9ae72cf2 libsystem_pthread.dylib`thread_start + 34
    thread #4, name = 'Finalizer'
      frame #0: 0x923c7fb6 libsystem_kernel.dylib`semaphore_wait_trap + 10
      frame #1: 0x002dbeb6 mono`finalizer_thread + 278
      frame #2: 0x002abb6b mono`start_wrapper + 795
      frame #3: 0x9ae6d5fb libsystem_pthread.dylib`_pthread_body + 144
      frame #4: 0x9ae6d485 libsystem_pthread.dylib`_pthread_start + 130
      frame #5: 0x9ae72cf2 libsystem_pthread.dylib`thread_start + 34
    thread #5, queue = 'com.apple.libdispatch-manager'
      frame #0: 0x923cd992 libsystem_kernel.dylib`kevent64 + 10
      frame #1: 0x91b5c899 libdispatch.dylib`_dispatch_mgr_invoke + 238
      frame #2: 0x91b5c532 libdispatch.dylib`_dispatch_mgr_thread + 52
    thread #6, name = 'tid_5a03'
      frame #0: 0x923ccace libsystem_kernel.dylib`__select + 10
      frame #1: 0x0036df29 mono`mono_poll + 409
      frame #2: 0x002b482f mono`poll_event_wait + 111
      frame #3: 0x002b345f mono`selector_thread + 1439
      frame #4: 0x002abb6b mono`start_wrapper + 795
      frame #5: 0x9ae6d5fb libsystem_pthread.dylib`_pthread_body + 144
      frame #6: 0x9ae6d485 libsystem_pthread.dylib`_pthread_start + 130
      frame #7: 0x9ae72cf2 libsystem_pthread.dylib`thread_start + 34
    thread #7, name = 'tid_4007'
      frame #0: 0x923cc7ca libsystem_kernel.dylib`__psynch_cvwait + 10
      frame #1: 0x9ae6fd1d libsystem_pthread.dylib`_pthread_cond_wait + 728
      frame #2: 0x9ae71c25 libsystem_pthread.dylib`pthread_cond_timedwait$UNIX2003 + 71
      frame #3: 0x003760f3 mono`mono_thread_info_sleep + 979
      frame #4: 0x002b1a86 mono`monitor_thread + 262
      frame #5: 0x002abb6b mono`start_wrapper + 795
      frame #6: 0x9ae6d5fb libsystem_pthread.dylib`_pthread_body + 144
      frame #7: 0x9ae6d485 libsystem_pthread.dylib`_pthread_start + 130
      frame #8: 0x9ae72cf2 libsystem_pthread.dylib`thread_start + 34
    thread #8, name = 'Threadpool worker'
      frame #0: 0x923cc7ca libsystem_kernel.dylib`__psynch_cvwait + 10
      frame #1: 0x9ae6fd1d libsystem_pthread.dylib`_pthread_cond_wait + 728
      frame #2: 0x9ae71c25 libsystem_pthread.dylib`pthread_cond_timedwait$UNIX2003 + 71
      frame #3: 0x002b12e0 mono`worker_thread + 1024
      frame #4: 0x002abb6b mono`start_wrapper + 795
      frame #5: 0x9ae6d5fb libsystem_pthread.dylib`_pthread_body + 144
      frame #6: 0x9ae6d485 libsystem_pthread.dylib`_pthread_start + 130
      frame #7: 0x9ae72cf2 libsystem_pthread.dylib`thread_start + 34
    thread #9, name = 'Threadpool worker'
      frame #0: 0x923cc7ca libsystem_kernel.dylib`__psynch_cvwait + 10
      frame #1: 0x9ae6fd1d libsystem_pthread.dylib`_pthread_cond_wait + 728
      frame #2: 0x9ae71c25 libsystem_pthread.dylib`pthread_cond_timedwait$UNIX2003 + 71
      frame #3: 0x002b12e0 mono`worker_thread + 1024
      frame #4: 0x002abb6b mono`start_wrapper + 795
      frame #5: 0x9ae6d5fb libsystem_pthread.dylib`_pthread_body + 144
      frame #6: 0x9ae6d485 libsystem_pthread.dylib`_pthread_start + 130
      frame #7: 0x9ae72cf2 libsystem_pthread.dylib`thread_start + 34
    thread #10, name = 'Domain unloader'
      frame #0: 0x923ccff2 libsystem_kernel.dylib`__wait4 + 10
      frame #1: 0x940d9ea5 libsystem_c.dylib`waitpid$UNIX2003 + 48
      frame #2: 0x0017cba7 mono`mono_handle_native_crash + 519
      frame #3: 0x001e2b03 mono`sigabrt_signal_handler + 147
      frame #4: 0x920a8deb libsystem_platform.dylib`_sigtramp + 43
  (lldb) detach
  Process 2037 detached
  (lldb) quit

  =================================================================
  Got a SIGABRT while executing native code. This usually indicates
  a fatal error in the mono runtime or one of the native libraries
  used by your application.
  =================================================================
```
@Rombersoft Rombersoft mentioned this pull request May 8, 2018
Closed
@lucasboulouys lucasboulouys mentioned this pull request Jun 28, 2018
Closed
lewurm pushed a commit to lewurm/mono that referenced this pull request Jul 27, 2018
@luhenry
[MiniCompiler] Move icall to mini.c (mono#26)
85e4575
@benjaminknox benjaminknox mentioned this pull request Aug 31, 2018
Closed
@dafrito dafrito mentioned this pull request Nov 16, 2018
Open
alexanderkyte added a commit to alexanderkyte/mono that referenced this pull request Jan 4, 2019
@alexanderkyte
[runtime] Add write barrier to end of JIT info table changes
78c1dde 
The MERP stress test often catches a crash like so:

```
 * frame #0: 0x0000000103409827 mono-sgen`mono_get_hazardous_pointer(pp=0x00007fc559a1a1f8, hp=0x00000001037e9600, hazard_index=1) at hazard-pointer.c:208
    frame mono#1: 0x000000010320eb8e mono-sgen`jit_info_table_chunk_index(chunk=0x00007fc4186060a0, hp=0x00000001037e9600, addr=0x00007fff73bffb66) at jit-info.c:200
    frame mono#2: 0x000000010320d7fa mono-sgen`jit_info_table_find(table=0x00007fc4186057c0, hp=0x00000001037e9600, addr=0x00007fff73bffb66) at jit-info.c:222
    frame mono#3: 0x000000010320d5e6 mono-sgen`mono_jit_info_table_find_internal(domain=0x00007fc418512bc0, addr=0x00007fff73bffb66, try_aot=1, allow_trampolines=1) at jit-info.c:293
    frame mono#4: 0x00000001030d67af mono-sgen`sigabrt_signal_handler(_dummy=6, _info=0x00007ffeecd4ea28, context=0x00007ffeecd4ea90) at mini-posix.c:219
    frame mono#5: 0x00007fff73dbdf5a libsystem_platform.dylib`_sigtramp + 26
    frame mono#6: 0x00007fff73bffb67 libsystem_kernel.dylib`__pthread_kill + 11
    frame mono#7: 0x00007fff73dca080 libsystem_pthread.dylib`pthread_kill + 333
    frame mono#8: 0x00007fff73b5b1ae libsystem_c.dylib`abort + 127
    frame mono#9: 0x00007fff73c59822 libsystem_malloc.dylib`free + 521
    frame mono#10: 0x0000000103c7d9d4 libtest.0.dylib`monoeg_g_free(ptr=0x00007ffeecd4ec34) at gmem.c:86
    frame mono#11: 0x0000000103c7733b libtest.0.dylib`mono_test_MerpCrashMalloc at libtest.c:7710
    frame mono#12: 0x0000000103c5c288
    frame mono#13: 0x000000010385dfd1
    frame mono#14: 0x0000000102ec85c3 mono-sgen`mono_jit_runtime_invoke(method=0x00007fc418514288, obj=0x0000000000000000, params=0x00007ffeecd4f180, exc=0x00007ffeecd4ef08, error=0x00007ffeecd4f250) at mini-runtime.c:3215
    frame mono#15: 0x000000010326f39d mono-sgen`do_runtime_invoke(method=0x00007fc418514288, obj=0x0000000000000000, params=0x00007ffeecd4f180, exc=0x0000000000000000, error=0x00007ffeecd4f250) at object.c:2977
    frame mono#16: 0x0000000103267c61 mono-sgen`mono_runtime_invoke_checked(method=0x00007fc418514288, obj=0x0000000000000000, params=0x00007ffeecd4f180, error=0x00007ffeecd4f250) at object.c:3145
    frame mono#17: 0x0000000103274d58 mono-sgen`do_exec_main_checked(method=0x00007fc418514288, args=0x00000001040003e8, error=0x00007ffeecd4f250) at object.c:5042
    frame mono#18: 0x0000000103272b03 mono-sgen`mono_runtime_exec_main_checked(method=0x00007fc418514288, args=0x00000001040003e8, error=0x00007ffeecd4f250) at object.c:5138
    frame mono#19: 0x0000000103272b56 mono-sgen`mono_runtime_run_main_checked(method=0x00007fc418514288, argc=2, argv=0x00007ffeecd4f760, error=0x00007ffeecd4f250) at object.c:4599
    frame mono#20: 0x0000000102f78bff mono-sgen`mono_jit_exec_internal(domain=0x00007fc418512bc0, assembly=0x00007fc4185445f0, argc=2, argv=0x00007ffeecd4f760) at driver.c:1298
    frame mono#21: 0x0000000102f78a2d mono-sgen`mono_jit_exec(domain=0x00007fc418512bc0, assembly=0x00007fc4185445f0, argc=2, argv=0x00007ffeecd4f760) at driver.c:1257
    frame mono#22: 0x0000000102f7d60f mono-sgen`main_thread_handler(user_data=0x00007ffeecd4f6a0) at driver.c:1375
    frame mono#23: 0x0000000102f7b8dd mono-sgen`mono_main(argc=3, argv=0x00007ffeecd4f758) at driver.c:2551
    frame mono#24: 0x0000000102eb1e4e mono-sgen`mono_main_with_options(argc=3, argv=0x00007ffeecd4f758) at main.c:50
    frame mono#25: 0x0000000102eb145d mono-sgen`main(argc=3, argv=0x00007ffeecd4f758) at main.c:406
    frame mono#26: 0x00007fff73aaf015 libdyld.dylib`start + 1
    frame mono#27: 0x00007fff73aaf015 libdyld.dylib`start + 1
```

because of

```
(lldb) p table->num_chunks
(int) $24 = 6
(lldb) p table->chunks [0]->num_elements
(volatile int) $18 = 50
(lldb) p table->chunks [1]->num_elements
(volatile int) $19 = 48
(lldb) p table->chunks [2]->num_elements
(volatile int) $20 = 48
(lldb) p table->chunks [3]->num_elements
(volatile int) $21 = 32
(lldb) p table->chunks [4]->num_elements
(volatile int) $23 = 32
(lldb) p table->chunks [5]->num_elements
(volatile int) $22 = 1347440720
```
.

It reproduces very often. Adding assertions / memory fences at the end
of the add/remove functions seems to remove this crash.

Looking at the code in the add function, I can picture how a missing
fence right at the end could lead to what we were seeing.

Not 100% happy with this fix, as it's going to have a perf cost. We have
an earlier fence that might be able to be coalesced into this one, but
the logic as-is makes that look unsafe.
alexanderkyte added a commit to alexanderkyte/mono that referenced this pull request Jan 7, 2019
@alexanderkyte
[runtime] Add write barrier to end of JIT info table changes
db9f0c2 
The MERP stress test often catches a crash like so:

```
 * frame #0: 0x0000000103409827 mono-sgen`mono_get_hazardous_pointer(pp=0x00007fc559a1a1f8, hp=0x00000001037e9600, hazard_index=1) at hazard-pointer.c:208
    frame mono#1: 0x000000010320eb8e mono-sgen`jit_info_table_chunk_index(chunk=0x00007fc4186060a0, hp=0x00000001037e9600, addr=0x00007fff73bffb66) at jit-info.c:200
    frame mono#2: 0x000000010320d7fa mono-sgen`jit_info_table_find(table=0x00007fc4186057c0, hp=0x00000001037e9600, addr=0x00007fff73bffb66) at jit-info.c:222
    frame mono#3: 0x000000010320d5e6 mono-sgen`mono_jit_info_table_find_internal(domain=0x00007fc418512bc0, addr=0x00007fff73bffb66, try_aot=1, allow_trampolines=1) at jit-info.c:293
    frame mono#4: 0x00000001030d67af mono-sgen`sigabrt_signal_handler(_dummy=6, _info=0x00007ffeecd4ea28, context=0x00007ffeecd4ea90) at mini-posix.c:219
    frame mono#5: 0x00007fff73dbdf5a libsystem_platform.dylib`_sigtramp + 26
    frame mono#6: 0x00007fff73bffb67 libsystem_kernel.dylib`__pthread_kill + 11
    frame mono#7: 0x00007fff73dca080 libsystem_pthread.dylib`pthread_kill + 333
    frame mono#8: 0x00007fff73b5b1ae libsystem_c.dylib`abort + 127
    frame mono#9: 0x00007fff73c59822 libsystem_malloc.dylib`free + 521
    frame mono#10: 0x0000000103c7d9d4 libtest.0.dylib`monoeg_g_free(ptr=0x00007ffeecd4ec34) at gmem.c:86
    frame mono#11: 0x0000000103c7733b libtest.0.dylib`mono_test_MerpCrashMalloc at libtest.c:7710
    frame mono#12: 0x0000000103c5c288
    frame mono#13: 0x000000010385dfd1
    frame mono#14: 0x0000000102ec85c3 mono-sgen`mono_jit_runtime_invoke(method=0x00007fc418514288, obj=0x0000000000000000, params=0x00007ffeecd4f180, exc=0x00007ffeecd4ef08, error=0x00007ffeecd4f250) at mini-runtime.c:3215
    frame mono#15: 0x000000010326f39d mono-sgen`do_runtime_invoke(method=0x00007fc418514288, obj=0x0000000000000000, params=0x00007ffeecd4f180, exc=0x0000000000000000, error=0x00007ffeecd4f250) at object.c:2977
    frame mono#16: 0x0000000103267c61 mono-sgen`mono_runtime_invoke_checked(method=0x00007fc418514288, obj=0x0000000000000000, params=0x00007ffeecd4f180, error=0x00007ffeecd4f250) at object.c:3145
    frame mono#17: 0x0000000103274d58 mono-sgen`do_exec_main_checked(method=0x00007fc418514288, args=0x00000001040003e8, error=0x00007ffeecd4f250) at object.c:5042
    frame mono#18: 0x0000000103272b03 mono-sgen`mono_runtime_exec_main_checked(method=0x00007fc418514288, args=0x00000001040003e8, error=0x00007ffeecd4f250) at object.c:5138
    frame mono#19: 0x0000000103272b56 mono-sgen`mono_runtime_run_main_checked(method=0x00007fc418514288, argc=2, argv=0x00007ffeecd4f760, error=0x00007ffeecd4f250) at object.c:4599
    frame mono#20: 0x0000000102f78bff mono-sgen`mono_jit_exec_internal(domain=0x00007fc418512bc0, assembly=0x00007fc4185445f0, argc=2, argv=0x00007ffeecd4f760) at driver.c:1298
    frame mono#21: 0x0000000102f78a2d mono-sgen`mono_jit_exec(domain=0x00007fc418512bc0, assembly=0x00007fc4185445f0, argc=2, argv=0x00007ffeecd4f760) at driver.c:1257
    frame mono#22: 0x0000000102f7d60f mono-sgen`main_thread_handler(user_data=0x00007ffeecd4f6a0) at driver.c:1375
    frame mono#23: 0x0000000102f7b8dd mono-sgen`mono_main(argc=3, argv=0x00007ffeecd4f758) at driver.c:2551
    frame mono#24: 0x0000000102eb1e4e mono-sgen`mono_main_with_options(argc=3, argv=0x00007ffeecd4f758) at main.c:50
    frame mono#25: 0x0000000102eb145d mono-sgen`main(argc=3, argv=0x00007ffeecd4f758) at main.c:406
    frame mono#26: 0x00007fff73aaf015 libdyld.dylib`start + 1
    frame mono#27: 0x00007fff73aaf015 libdyld.dylib`start + 1
```

because of

```
(lldb) p table->num_chunks
(int) $24 = 6
(lldb) p table->chunks [0]->num_elements
(volatile int) $18 = 50
(lldb) p table->chunks [1]->num_elements
(volatile int) $19 = 48
(lldb) p table->chunks [2]->num_elements
(volatile int) $20 = 48
(lldb) p table->chunks [3]->num_elements
(volatile int) $21 = 32
(lldb) p table->chunks [4]->num_elements
(volatile int) $23 = 32
(lldb) p table->chunks [5]->num_elements
(volatile int) $22 = 1347440720
```
.

It reproduces very often. Adding assertions / memory fences at the end
of the add/remove functions seems to remove this crash.

Looking at the code in the add function, I can picture how a missing
fence right at the end could lead to what we were seeing.

Not 100% happy with this fix, as it's going to have a perf cost. We have
an earlier fence that might be able to be coalesced into this one, but
the logic as-is makes that look unsafe.
alexanderkyte added a commit to alexanderkyte/mono that referenced this pull request Jan 7, 2019
@alexanderkyte
[runtime] Add write barrier to end of JIT info table changes
ceb3704 
The MERP stress test often catches a crash like so:

```
 * frame #0: 0x0000000103409827 mono-sgen`mono_get_hazardous_pointer(pp=0x00007fc559a1a1f8, hp=0x00000001037e9600, hazard_index=1) at hazard-pointer.c:208
    frame mono#1: 0x000000010320eb8e mono-sgen`jit_info_table_chunk_index(chunk=0x00007fc4186060a0, hp=0x00000001037e9600, addr=0x00007fff73bffb66) at jit-info.c:200
    frame mono#2: 0x000000010320d7fa mono-sgen`jit_info_table_find(table=0x00007fc4186057c0, hp=0x00000001037e9600, addr=0x00007fff73bffb66) at jit-info.c:222
    frame mono#3: 0x000000010320d5e6 mono-sgen`mono_jit_info_table_find_internal(domain=0x00007fc418512bc0, addr=0x00007fff73bffb66, try_aot=1, allow_trampolines=1) at jit-info.c:293
    frame mono#4: 0x00000001030d67af mono-sgen`sigabrt_signal_handler(_dummy=6, _info=0x00007ffeecd4ea28, context=0x00007ffeecd4ea90) at mini-posix.c:219
    frame mono#5: 0x00007fff73dbdf5a libsystem_platform.dylib`_sigtramp + 26
    frame mono#6: 0x00007fff73bffb67 libsystem_kernel.dylib`__pthread_kill + 11
    frame mono#7: 0x00007fff73dca080 libsystem_pthread.dylib`pthread_kill + 333
    frame mono#8: 0x00007fff73b5b1ae libsystem_c.dylib`abort + 127
    frame mono#9: 0x00007fff73c59822 libsystem_malloc.dylib`free + 521
    frame mono#10: 0x0000000103c7d9d4 libtest.0.dylib`monoeg_g_free(ptr=0x00007ffeecd4ec34) at gmem.c:86
    frame mono#11: 0x0000000103c7733b libtest.0.dylib`mono_test_MerpCrashMalloc at libtest.c:7710
    frame mono#12: 0x0000000103c5c288
    frame mono#13: 0x000000010385dfd1
    frame mono#14: 0x0000000102ec85c3 mono-sgen`mono_jit_runtime_invoke(method=0x00007fc418514288, obj=0x0000000000000000, params=0x00007ffeecd4f180, exc=0x00007ffeecd4ef08, error=0x00007ffeecd4f250) at mini-runtime.c:3215
    frame mono#15: 0x000000010326f39d mono-sgen`do_runtime_invoke(method=0x00007fc418514288, obj=0x0000000000000000, params=0x00007ffeecd4f180, exc=0x0000000000000000, error=0x00007ffeecd4f250) at object.c:2977
    frame mono#16: 0x0000000103267c61 mono-sgen`mono_runtime_invoke_checked(method=0x00007fc418514288, obj=0x0000000000000000, params=0x00007ffeecd4f180, error=0x00007ffeecd4f250) at object.c:3145
    frame mono#17: 0x0000000103274d58 mono-sgen`do_exec_main_checked(method=0x00007fc418514288, args=0x00000001040003e8, error=0x00007ffeecd4f250) at object.c:5042
    frame mono#18: 0x0000000103272b03 mono-sgen`mono_runtime_exec_main_checked(method=0x00007fc418514288, args=0x00000001040003e8, error=0x00007ffeecd4f250) at object.c:5138
    frame mono#19: 0x0000000103272b56 mono-sgen`mono_runtime_run_main_checked(method=0x00007fc418514288, argc=2, argv=0x00007ffeecd4f760, error=0x00007ffeecd4f250) at object.c:4599
    frame mono#20: 0x0000000102f78bff mono-sgen`mono_jit_exec_internal(domain=0x00007fc418512bc0, assembly=0x00007fc4185445f0, argc=2, argv=0x00007ffeecd4f760) at driver.c:1298
    frame mono#21: 0x0000000102f78a2d mono-sgen`mono_jit_exec(domain=0x00007fc418512bc0, assembly=0x00007fc4185445f0, argc=2, argv=0x00007ffeecd4f760) at driver.c:1257
    frame mono#22: 0x0000000102f7d60f mono-sgen`main_thread_handler(user_data=0x00007ffeecd4f6a0) at driver.c:1375
    frame mono#23: 0x0000000102f7b8dd mono-sgen`mono_main(argc=3, argv=0x00007ffeecd4f758) at driver.c:2551
    frame mono#24: 0x0000000102eb1e4e mono-sgen`mono_main_with_options(argc=3, argv=0x00007ffeecd4f758) at main.c:50
    frame mono#25: 0x0000000102eb145d mono-sgen`main(argc=3, argv=0x00007ffeecd4f758) at main.c:406
    frame mono#26: 0x00007fff73aaf015 libdyld.dylib`start + 1
    frame mono#27: 0x00007fff73aaf015 libdyld.dylib`start + 1
```

because of

```
(lldb) p table->num_chunks
(int) $24 = 6
(lldb) p table->chunks [0]->num_elements
(volatile int) $18 = 50
(lldb) p table->chunks [1]->num_elements
(volatile int) $19 = 48
(lldb) p table->chunks [2]->num_elements
(volatile int) $20 = 48
(lldb) p table->chunks [3]->num_elements
(volatile int) $21 = 32
(lldb) p table->chunks [4]->num_elements
(volatile int) $23 = 32
(lldb) p table->chunks [5]->num_elements
(volatile int) $22 = 1347440720
```
.

It reproduces very often. Adding assertions / memory fences at the end
of the add/remove functions seems to remove this crash.

Looking at the code in the add function, I can picture how a missing
fence right at the end could lead to what we were seeing.

Not 100% happy with this fix, as it's going to have a perf cost. We have
an earlier fence that might be able to be coalesced into this one, but
the logic as-is makes that look unsafe.
alexanderkyte added a commit to alexanderkyte/mono that referenced this pull request Jan 11, 2019
@alexanderkyte
[runtime] Add write barrier to end of JIT info table changes
3e741b3 
The MERP stress test often catches a crash like so:

```
 * frame #0: 0x0000000103409827 mono-sgen`mono_get_hazardous_pointer(pp=0x00007fc559a1a1f8, hp=0x00000001037e9600, hazard_index=1) at hazard-pointer.c:208
    frame mono#1: 0x000000010320eb8e mono-sgen`jit_info_table_chunk_index(chunk=0x00007fc4186060a0, hp=0x00000001037e9600, addr=0x00007fff73bffb66) at jit-info.c:200
    frame mono#2: 0x000000010320d7fa mono-sgen`jit_info_table_find(table=0x00007fc4186057c0, hp=0x00000001037e9600, addr=0x00007fff73bffb66) at jit-info.c:222
    frame mono#3: 0x000000010320d5e6 mono-sgen`mono_jit_info_table_find_internal(domain=0x00007fc418512bc0, addr=0x00007fff73bffb66, try_aot=1, allow_trampolines=1) at jit-info.c:293
    frame mono#4: 0x00000001030d67af mono-sgen`sigabrt_signal_handler(_dummy=6, _info=0x00007ffeecd4ea28, context=0x00007ffeecd4ea90) at mini-posix.c:219
    frame mono#5: 0x00007fff73dbdf5a libsystem_platform.dylib`_sigtramp + 26
    frame mono#6: 0x00007fff73bffb67 libsystem_kernel.dylib`__pthread_kill + 11
    frame mono#7: 0x00007fff73dca080 libsystem_pthread.dylib`pthread_kill + 333
    frame mono#8: 0x00007fff73b5b1ae libsystem_c.dylib`abort + 127
    frame mono#9: 0x00007fff73c59822 libsystem_malloc.dylib`free + 521
    frame mono#10: 0x0000000103c7d9d4 libtest.0.dylib`monoeg_g_free(ptr=0x00007ffeecd4ec34) at gmem.c:86
    frame mono#11: 0x0000000103c7733b libtest.0.dylib`mono_test_MerpCrashMalloc at libtest.c:7710
    frame mono#12: 0x0000000103c5c288
    frame mono#13: 0x000000010385dfd1
    frame mono#14: 0x0000000102ec85c3 mono-sgen`mono_jit_runtime_invoke(method=0x00007fc418514288, obj=0x0000000000000000, params=0x00007ffeecd4f180, exc=0x00007ffeecd4ef08, error=0x00007ffeecd4f250) at mini-runtime.c:3215
    frame mono#15: 0x000000010326f39d mono-sgen`do_runtime_invoke(method=0x00007fc418514288, obj=0x0000000000000000, params=0x00007ffeecd4f180, exc=0x0000000000000000, error=0x00007ffeecd4f250) at object.c:2977
    frame mono#16: 0x0000000103267c61 mono-sgen`mono_runtime_invoke_checked(method=0x00007fc418514288, obj=0x0000000000000000, params=0x00007ffeecd4f180, error=0x00007ffeecd4f250) at object.c:3145
    frame mono#17: 0x0000000103274d58 mono-sgen`do_exec_main_checked(method=0x00007fc418514288, args=0x00000001040003e8, error=0x00007ffeecd4f250) at object.c:5042
    frame mono#18: 0x0000000103272b03 mono-sgen`mono_runtime_exec_main_checked(method=0x00007fc418514288, args=0x00000001040003e8, error=0x00007ffeecd4f250) at object.c:5138
    frame mono#19: 0x0000000103272b56 mono-sgen`mono_runtime_run_main_checked(method=0x00007fc418514288, argc=2, argv=0x00007ffeecd4f760, error=0x00007ffeecd4f250) at object.c:4599
    frame mono#20: 0x0000000102f78bff mono-sgen`mono_jit_exec_internal(domain=0x00007fc418512bc0, assembly=0x00007fc4185445f0, argc=2, argv=0x00007ffeecd4f760) at driver.c:1298
    frame mono#21: 0x0000000102f78a2d mono-sgen`mono_jit_exec(domain=0x00007fc418512bc0, assembly=0x00007fc4185445f0, argc=2, argv=0x00007ffeecd4f760) at driver.c:1257
    frame mono#22: 0x0000000102f7d60f mono-sgen`main_thread_handler(user_data=0x00007ffeecd4f6a0) at driver.c:1375
    frame mono#23: 0x0000000102f7b8dd mono-sgen`mono_main(argc=3, argv=0x00007ffeecd4f758) at driver.c:2551
    frame mono#24: 0x0000000102eb1e4e mono-sgen`mono_main_with_options(argc=3, argv=0x00007ffeecd4f758) at main.c:50
    frame mono#25: 0x0000000102eb145d mono-sgen`main(argc=3, argv=0x00007ffeecd4f758) at main.c:406
    frame mono#26: 0x00007fff73aaf015 libdyld.dylib`start + 1
    frame mono#27: 0x00007fff73aaf015 libdyld.dylib`start + 1
```

because of

```
(lldb) p table->num_chunks
(int) $24 = 6
(lldb) p table->chunks [0]->num_elements
(volatile int) $18 = 50
(lldb) p table->chunks [1]->num_elements
(volatile int) $19 = 48
(lldb) p table->chunks [2]->num_elements
(volatile int) $20 = 48
(lldb) p table->chunks [3]->num_elements
(volatile int) $21 = 32
(lldb) p table->chunks [4]->num_elements
(volatile int) $23 = 32
(lldb) p table->chunks [5]->num_elements
(volatile int) $22 = 1347440720
```
.

It reproduces very often. Adding assertions / memory fences at the end
of the add/remove functions seems to remove this crash.

Looking at the code in the add function, I can picture how a missing
fence right at the end could lead to what we were seeing.

Not 100% happy with this fix, as it's going to have a perf cost. We have
an earlier fence that might be able to be coalesced into this one, but
the logic as-is makes that look unsafe.
lewurm added a commit to lewurm/mono that referenced this pull request Feb 1, 2019
@lewurm
Bump corert
38d3bc9 
Commit list for mono/corert:

* mono/corert@1b7d4a1e4 [Number] make double 0.0 cmp more portable (mono#30)
* mono/corert@c4ae51646 Update ISOWeek.cs
* mono/corert@7e8bf2382 fix ISOWeek for mcs
* mono/corert@0e5f123f6 [corlib] Import System.IO.Stream/BufferedStream from CoreFX (mono#26)

Diff: mono/corert@b6a822b...1b7d4a1
This was referenced Feb 1, 2019
Merged
Merged
marek-safar pushed a commit that referenced this pull request Feb 4, 2019
@lewurm @marek-safar
Bump corert
548744c 
Commit list for mono/corert:

* mono/corert@1b7d4a1e4 [Number] make double 0.0 cmp more portable (#30)
* mono/corert@c4ae51646 Update ISOWeek.cs
* mono/corert@7e8bf2382 fix ISOWeek for mcs
* mono/corert@0e5f123f6 [corlib] Import System.IO.Stream/BufferedStream from CoreFX (#26)

Diff: mono/corert@b6a822b...1b7d4a1
@lateralusX lateralusX mentioned this pull request Mar 7, 2019
Merged
@MattL0 MattL0 mentioned this pull request Jul 18, 2019
Closed
lewurm added a commit to lewurm/mono that referenced this pull request Sep 20, 2019
@lewurm
[threads] clear small_id_key TLS when unregistering a thread
3a9ed64 
Fixes
```
* thread mono#12, name = 'tid_a507', stop reason = EXC_BREAKPOINT (code=1, subcode=0x1be66144)
  * frame #0: 0x1be66144 libsystem_c.dylib`__abort + 184
    frame #1: 0x1be6608c libsystem_c.dylib`abort + 152
    frame #2: 0x003e1fa0 monotouchtest`log_callback(log_domain=0x00000000, log_level="error", message="* Assertion at ../../../../../mono/utils/hazard-pointer.c:158, condition `mono_bitset_test_fast (small_id_table, id)' not met\n", fatal=4, user_data=0x00000000) at runtime.m:1251:3
    frame mono#3: 0x003abf44 monotouchtest`monoeg_g_logv_nofree(log_domain=0x00000000, log_level=G_LOG_LEVEL_ERROR, format=<unavailable>, args=<unavailable>) at goutput.c:149:2 [opt]
    frame mono#4: 0x003abfb4 monotouchtest`monoeg_assertion_message(format=<unavailable>) at goutput.c:184:22 [opt]
    frame mono#5: 0x003904dc monotouchtest`mono_thread_small_id_free(id=<unavailable>) at hazard-pointer.c:0:2 [opt]
    frame mono#6: 0x003a0a74 monotouchtest`unregister_thread(arg=0x15c88400) at mono-threads.c:588:2 [opt]
    frame mono#7: 0x00336110 monotouchtest`mono_thread_detach_if_exiting at threads.c:1571:4 [opt]
    frame mono#8: 0x003e7a14 monotouchtest`::xamarin_release_trampoline(self=0x166452f0, sel="release") at trampolines.m:644:3
    frame mono#9: 0x001cdc40 monotouchtest`::-[__Xamarin_NSTimerActionDispatcher release](self=0x166452f0, _cmd="release") at registrar.m:83445:3
    frame mono#10: 0x1ce2ae68 Foundation`_timerRelease + 80
    frame mono#11: 0x1c31b56c CoreFoundation`CFRunLoopTimerInvalidate + 612
    frame mono#12: 0x1c31a554 CoreFoundation`__CFRunLoopTimerDeallocate + 32
    frame mono#13: 0x1c31dde4 CoreFoundation`_CFRelease + 220
    frame mono#14: 0x1c2be6e8 CoreFoundation`__CFArrayReleaseValues + 500
    frame mono#15: 0x1c2be4c4 CoreFoundation`CFArrayRemoveAllValues + 104
    frame mono#16: 0x1c31ff64 CoreFoundation`__CFSetApplyFunction_block_invoke + 24
    frame mono#17: 0x1c3b2e18 CoreFoundation`CFBasicHashApply + 116
    frame mono#18: 0x1c31ff10 CoreFoundation`CFSetApplyFunction + 160
    frame mono#19: 0x1c3152cc CoreFoundation`__CFRunLoopDeallocate + 204
    frame mono#20: 0x1c31dde4 CoreFoundation`_CFRelease + 220
    frame mono#21: 0x1c304a80 CoreFoundation`__CFTSDFinalize + 144
    frame mono#22: 0x1bfa324c libsystem_pthread.dylib`_pthread_tsd_cleanup + 644
    frame mono#23: 0x1bf9cc08 libsystem_pthread.dylib`_pthread_exit + 80
    frame mono#24: 0x1bf9af24 libsystem_pthread.dylib`pthread_exit + 36
    frame mono#25: 0x0039df84 monotouchtest`mono_threads_platform_exit(exit_code=<unavailable>) at mono-threads-posix.c:145:2 [opt]
    frame mono#26: 0x0033bb84 monotouchtest`start_wrapper(data=0x1609e1c0) at threads.c:1296:2 [opt]
    frame mono#27: 0x1bf9b914 libsystem_pthread.dylib`_pthread_body + 128
    frame mono#28: 0x1bf9b874 libsystem_pthread.dylib`_pthread_start + 44
    frame mono#29: 0x1bfa3b94 libsystem_pthread.dylib`thread_start + 4
```
lewurm added a commit to lewurm/mono that referenced this pull request Sep 20, 2019
@lewurm
[threads] clear small_id_key TLS when unregistering a thread
fafb38d 
Fixes
```
* thread mono#12, name = 'tid_a507', stop reason = EXC_BREAKPOINT (code=1, subcode=0x1be66144)
  * frame #0: 0x1be66144 libsystem_c.dylib`__abort + 184
    frame #1: 0x1be6608c libsystem_c.dylib`abort + 152
    frame #2: 0x003e1fa0 monotouchtest`log_callback(log_domain=0x00000000, log_level="error", message="* Assertion at ../../../../../mono/utils/hazard-pointer.c:158, condition `mono_bitset_test_fast (small_id_table, id)' not met\n", fatal=4, user_data=0x00000000) at runtime.m:1251:3
    frame mono#3: 0x003abf44 monotouchtest`monoeg_g_logv_nofree(log_domain=0x00000000, log_level=G_LOG_LEVEL_ERROR, format=<unavailable>, args=<unavailable>) at goutput.c:149:2 [opt]
    frame mono#4: 0x003abfb4 monotouchtest`monoeg_assertion_message(format=<unavailable>) at goutput.c:184:22 [opt]
    frame mono#5: 0x003904dc monotouchtest`mono_thread_small_id_free(id=<unavailable>) at hazard-pointer.c:0:2 [opt]
    frame mono#6: 0x003a0a74 monotouchtest`unregister_thread(arg=0x15c88400) at mono-threads.c:588:2 [opt]
    frame mono#7: 0x00336110 monotouchtest`mono_thread_detach_if_exiting at threads.c:1571:4 [opt]
    frame mono#8: 0x003e7a14 monotouchtest`::xamarin_release_trampoline(self=0x166452f0, sel="release") at trampolines.m:644:3
    frame mono#9: 0x001cdc40 monotouchtest`::-[__Xamarin_NSTimerActionDispatcher release](self=0x166452f0, _cmd="release") at registrar.m:83445:3
    frame mono#10: 0x1ce2ae68 Foundation`_timerRelease + 80
    frame mono#11: 0x1c31b56c CoreFoundation`CFRunLoopTimerInvalidate + 612
    frame mono#12: 0x1c31a554 CoreFoundation`__CFRunLoopTimerDeallocate + 32
    frame mono#13: 0x1c31dde4 CoreFoundation`_CFRelease + 220
    frame mono#14: 0x1c2be6e8 CoreFoundation`__CFArrayReleaseValues + 500
    frame mono#15: 0x1c2be4c4 CoreFoundation`CFArrayRemoveAllValues + 104
    frame mono#16: 0x1c31ff64 CoreFoundation`__CFSetApplyFunction_block_invoke + 24
    frame mono#17: 0x1c3b2e18 CoreFoundation`CFBasicHashApply + 116
    frame mono#18: 0x1c31ff10 CoreFoundation`CFSetApplyFunction + 160
    frame mono#19: 0x1c3152cc CoreFoundation`__CFRunLoopDeallocate + 204
    frame mono#20: 0x1c31dde4 CoreFoundation`_CFRelease + 220
    frame mono#21: 0x1c304a80 CoreFoundation`__CFTSDFinalize + 144
    frame mono#22: 0x1bfa324c libsystem_pthread.dylib`_pthread_tsd_cleanup + 644
    frame mono#23: 0x1bf9cc08 libsystem_pthread.dylib`_pthread_exit + 80
    frame mono#24: 0x1bf9af24 libsystem_pthread.dylib`pthread_exit + 36
    frame mono#25: 0x0039df84 monotouchtest`mono_threads_platform_exit(exit_code=<unavailable>) at mono-threads-posix.c:145:2 [opt]
    frame mono#26: 0x0033bb84 monotouchtest`start_wrapper(data=0x1609e1c0) at threads.c:1296:2 [opt]
    frame mono#27: 0x1bf9b914 libsystem_pthread.dylib`_pthread_body + 128
    frame mono#28: 0x1bf9b874 libsystem_pthread.dylib`_pthread_start + 44
    frame mono#29: 0x1bfa3b94 libsystem_pthread.dylib`thread_start + 4
```
lewurm added a commit that referenced this pull request Sep 24, 2019
@lewurm @lambdageek
[threads] clear small_id_key TLS when unregistering a thread (#16973)
749493d 
* [threads] clear small_id_key TLS when unregistering a thread

Fixes
```
* thread #12, name = 'tid_a507', stop reason = EXC_BREAKPOINT (code=1, subcode=0x1be66144)
  * frame #0: 0x1be66144 libsystem_c.dylib`__abort + 184
    frame #1: 0x1be6608c libsystem_c.dylib`abort + 152
    frame #2: 0x003e1fa0 monotouchtest`log_callback(log_domain=0x00000000, log_level="error", message="* Assertion at ../../../../../mono/utils/hazard-pointer.c:158, condition `mono_bitset_test_fast (small_id_table, id)' not met\n", fatal=4, user_data=0x00000000) at runtime.m:1251:3
    frame #3: 0x003abf44 monotouchtest`monoeg_g_logv_nofree(log_domain=0x00000000, log_level=G_LOG_LEVEL_ERROR, format=<unavailable>, args=<unavailable>) at goutput.c:149:2 [opt]
    frame #4: 0x003abfb4 monotouchtest`monoeg_assertion_message(format=<unavailable>) at goutput.c:184:22 [opt]
    frame #5: 0x003904dc monotouchtest`mono_thread_small_id_free(id=<unavailable>) at hazard-pointer.c:0:2 [opt]
    frame #6: 0x003a0a74 monotouchtest`unregister_thread(arg=0x15c88400) at mono-threads.c:588:2 [opt]
    frame #7: 0x00336110 monotouchtest`mono_thread_detach_if_exiting at threads.c:1571:4 [opt]
    frame #8: 0x003e7a14 monotouchtest`::xamarin_release_trampoline(self=0x166452f0, sel="release") at trampolines.m:644:3
    frame #9: 0x001cdc40 monotouchtest`::-[__Xamarin_NSTimerActionDispatcher release](self=0x166452f0, _cmd="release") at registrar.m:83445:3
    frame #10: 0x1ce2ae68 Foundation`_timerRelease + 80
    frame #11: 0x1c31b56c CoreFoundation`CFRunLoopTimerInvalidate + 612
    frame #12: 0x1c31a554 CoreFoundation`__CFRunLoopTimerDeallocate + 32
    frame #13: 0x1c31dde4 CoreFoundation`_CFRelease + 220
    frame #14: 0x1c2be6e8 CoreFoundation`__CFArrayReleaseValues + 500
    frame #15: 0x1c2be4c4 CoreFoundation`CFArrayRemoveAllValues + 104
    frame #16: 0x1c31ff64 CoreFoundation`__CFSetApplyFunction_block_invoke + 24
    frame #17: 0x1c3b2e18 CoreFoundation`CFBasicHashApply + 116
    frame #18: 0x1c31ff10 CoreFoundation`CFSetApplyFunction + 160
    frame #19: 0x1c3152cc CoreFoundation`__CFRunLoopDeallocate + 204
    frame #20: 0x1c31dde4 CoreFoundation`_CFRelease + 220
    frame #21: 0x1c304a80 CoreFoundation`__CFTSDFinalize + 144
    frame #22: 0x1bfa324c libsystem_pthread.dylib`_pthread_tsd_cleanup + 644
    frame #23: 0x1bf9cc08 libsystem_pthread.dylib`_pthread_exit + 80
    frame #24: 0x1bf9af24 libsystem_pthread.dylib`pthread_exit + 36
    frame #25: 0x0039df84 monotouchtest`mono_threads_platform_exit(exit_code=<unavailable>) at mono-threads-posix.c:145:2 [opt]
    frame #26: 0x0033bb84 monotouchtest`start_wrapper(data=0x1609e1c0) at threads.c:1296:2 [opt]
    frame #27: 0x1bf9b914 libsystem_pthread.dylib`_pthread_body + 128
    frame #28: 0x1bf9b874 libsystem_pthread.dylib`_pthread_start + 44
    frame #29: 0x1bfa3b94 libsystem_pthread.dylib`thread_start + 4
```

* Update mono/utils/mono-threads.c

Co-Authored-By: Aleksey Kliger (λgeek) <akliger@gmail.com>
monojenkins pushed a commit to monojenkins/mono that referenced this pull request Sep 24, 2019
@lewurm @monojenkins
[threads] clear small_id_key TLS when unregistering a thread
c2dc2b9 
Fixes
```
* thread mono#12, name = 'tid_a507', stop reason = EXC_BREAKPOINT (code=1, subcode=0x1be66144)
  * frame #0: 0x1be66144 libsystem_c.dylib`__abort + 184
    frame mono#1: 0x1be6608c libsystem_c.dylib`abort + 152
    frame mono#2: 0x003e1fa0 monotouchtest`log_callback(log_domain=0x00000000, log_level="error", message="* Assertion at ../../../../../mono/utils/hazard-pointer.c:158, condition `mono_bitset_test_fast (small_id_table, id)' not met\n", fatal=4, user_data=0x00000000) at runtime.m:1251:3
    frame mono#3: 0x003abf44 monotouchtest`monoeg_g_logv_nofree(log_domain=0x00000000, log_level=G_LOG_LEVEL_ERROR, format=<unavailable>, args=<unavailable>) at goutput.c:149:2 [opt]
    frame mono#4: 0x003abfb4 monotouchtest`monoeg_assertion_message(format=<unavailable>) at goutput.c:184:22 [opt]
    frame mono#5: 0x003904dc monotouchtest`mono_thread_small_id_free(id=<unavailable>) at hazard-pointer.c:0:2 [opt]
    frame mono#6: 0x003a0a74 monotouchtest`unregister_thread(arg=0x15c88400) at mono-threads.c:588:2 [opt]
    frame mono#7: 0x00336110 monotouchtest`mono_thread_detach_if_exiting at threads.c:1571:4 [opt]
    frame mono#8: 0x003e7a14 monotouchtest`::xamarin_release_trampoline(self=0x166452f0, sel="release") at trampolines.m:644:3
    frame mono#9: 0x001cdc40 monotouchtest`::-[__Xamarin_NSTimerActionDispatcher release](self=0x166452f0, _cmd="release") at registrar.m:83445:3
    frame mono#10: 0x1ce2ae68 Foundation`_timerRelease + 80
    frame mono#11: 0x1c31b56c CoreFoundation`CFRunLoopTimerInvalidate + 612
    frame mono#12: 0x1c31a554 CoreFoundation`__CFRunLoopTimerDeallocate + 32
    frame mono#13: 0x1c31dde4 CoreFoundation`_CFRelease + 220
    frame mono#14: 0x1c2be6e8 CoreFoundation`__CFArrayReleaseValues + 500
    frame mono#15: 0x1c2be4c4 CoreFoundation`CFArrayRemoveAllValues + 104
    frame mono#16: 0x1c31ff64 CoreFoundation`__CFSetApplyFunction_block_invoke + 24
    frame mono#17: 0x1c3b2e18 CoreFoundation`CFBasicHashApply + 116
    frame mono#18: 0x1c31ff10 CoreFoundation`CFSetApplyFunction + 160
    frame mono#19: 0x1c3152cc CoreFoundation`__CFRunLoopDeallocate + 204
    frame mono#20: 0x1c31dde4 CoreFoundation`_CFRelease + 220
    frame mono#21: 0x1c304a80 CoreFoundation`__CFTSDFinalize + 144
    frame mono#22: 0x1bfa324c libsystem_pthread.dylib`_pthread_tsd_cleanup + 644
    frame mono#23: 0x1bf9cc08 libsystem_pthread.dylib`_pthread_exit + 80
    frame mono#24: 0x1bf9af24 libsystem_pthread.dylib`pthread_exit + 36
    frame mono#25: 0x0039df84 monotouchtest`mono_threads_platform_exit(exit_code=<unavailable>) at mono-threads-posix.c:145:2 [opt]
    frame mono#26: 0x0033bb84 monotouchtest`start_wrapper(data=0x1609e1c0) at threads.c:1296:2 [opt]
    frame mono#27: 0x1bf9b914 libsystem_pthread.dylib`_pthread_body + 128
    frame mono#28: 0x1bf9b874 libsystem_pthread.dylib`_pthread_start + 44
    frame mono#29: 0x1bfa3b94 libsystem_pthread.dylib`thread_start + 4
```
monojenkins added a commit that referenced this pull request Sep 24, 2019
@monojenkins
[2019-08] [threads] clear small_id_key TLS when unregistering a thread (
af008b2 
#17015)

[2019-08] [threads] clear small_id_key TLS when unregistering a thread

Fixes
```
* thread #12, name = 'tid_a507', stop reason = EXC_BREAKPOINT (code=1, subcode=0x1be66144)
  * frame #0: 0x1be66144 libsystem_c.dylib`__abort + 184
    frame #1: 0x1be6608c libsystem_c.dylib`abort + 152
    frame #2: 0x003e1fa0 monotouchtest`log_callback(log_domain=0x00000000, log_level="error", message="* Assertion at ../../../../../mono/utils/hazard-pointer.c:158, condition `mono_bitset_test_fast (small_id_table, id)' not met\n", fatal=4, user_data=0x00000000) at runtime.m:1251:3
    frame #3: 0x003abf44 monotouchtest`monoeg_g_logv_nofree(log_domain=0x00000000, log_level=G_LOG_LEVEL_ERROR, format=<unavailable>, args=<unavailable>) at goutput.c:149:2 [opt]
    frame #4: 0x003abfb4 monotouchtest`monoeg_assertion_message(format=<unavailable>) at goutput.c:184:22 [opt]
    frame #5: 0x003904dc monotouchtest`mono_thread_small_id_free(id=<unavailable>) at hazard-pointer.c:0:2 [opt]
    frame #6: 0x003a0a74 monotouchtest`unregister_thread(arg=0x15c88400) at mono-threads.c:588:2 [opt]
    frame #7: 0x00336110 monotouchtest`mono_thread_detach_if_exiting at threads.c:1571:4 [opt]
    frame #8: 0x003e7a14 monotouchtest`::xamarin_release_trampoline(self=0x166452f0, sel="release") at trampolines.m:644:3
    frame #9: 0x001cdc40 monotouchtest`::-[__Xamarin_NSTimerActionDispatcher release](self=0x166452f0, _cmd="release") at registrar.m:83445:3
    frame #10: 0x1ce2ae68 Foundation`_timerRelease + 80
    frame #11: 0x1c31b56c CoreFoundation`CFRunLoopTimerInvalidate + 612
    frame #12: 0x1c31a554 CoreFoundation`__CFRunLoopTimerDeallocate + 32
    frame #13: 0x1c31dde4 CoreFoundation`_CFRelease + 220
    frame #14: 0x1c2be6e8 CoreFoundation`__CFArrayReleaseValues + 500
    frame #15: 0x1c2be4c4 CoreFoundation`CFArrayRemoveAllValues + 104
    frame #16: 0x1c31ff64 CoreFoundation`__CFSetApplyFunction_block_invoke + 24
    frame #17: 0x1c3b2e18 CoreFoundation`CFBasicHashApply + 116
    frame #18: 0x1c31ff10 CoreFoundation`CFSetApplyFunction + 160
    frame #19: 0x1c3152cc CoreFoundation`__CFRunLoopDeallocate + 204
    frame #20: 0x1c31dde4 CoreFoundation`_CFRelease + 220
    frame #21: 0x1c304a80 CoreFoundation`__CFTSDFinalize + 144
    frame #22: 0x1bfa324c libsystem_pthread.dylib`_pthread_tsd_cleanup + 644
    frame #23: 0x1bf9cc08 libsystem_pthread.dylib`_pthread_exit + 80
    frame #24: 0x1bf9af24 libsystem_pthread.dylib`pthread_exit + 36
    frame #25: 0x0039df84 monotouchtest`mono_threads_platform_exit(exit_code=<unavailable>) at mono-threads-posix.c:145:2 [opt]
    frame #26: 0x0033bb84 monotouchtest`start_wrapper(data=0x1609e1c0) at threads.c:1296:2 [opt]
    frame #27: 0x1bf9b914 libsystem_pthread.dylib`_pthread_body + 128
    frame #28: 0x1bf9b874 libsystem_pthread.dylib`_pthread_start + 44
    frame #29: 0x1bfa3b94 libsystem_pthread.dylib`thread_start + 4
```


Debugged by @lambdageek. Contributes to #10641

Edit: C/p into PR description so it's in the commit message:

We think what happens is:

1. `start_wrapper` runs `unregister_thread` when the thread is exiting.  At that point the `small_id` for the thread is cleared from the hazard pointer bitset by `mono_thread_small_id_free (small_id)`

2. Some other TLS destructor runs and attaches the thread again (which runs `mono_thread_info_register_small_id` which first calls `mono_thread_info_get_small_id` which tries to get the small id from the `small_id_key` TLS key and so the new `MonoThreadInfo` has the same `small_id` as the previously destroyed `MonoThreadInfo` - but the hazard pointer bitset is **not** updated).

3. This other TLS destructor runs and calls `mono_thread_detach_if_exiting` which calls `unregister_thread` again.

4. `unregister_thread` calls `	mono_thread_small_id_free (small_id)` a second time which asserts because we already cleared that id from the hazard pointer bitset.



Backport of #16973.

/cc @lewurm
@fanyang-mono fanyang-mono mentioned this pull request Dec 9, 2019
Closed
lewurm added a commit to lewurm/mono that referenced this pull request Dec 9, 2019
@lewurm
[debugger] skip suspend for unattached threads
a6d8b0e 
When the debugger tries to suspend all the VM threads, it can happen with cooperative-suspend that it tries to suspend a thread that has previously been attached, but then did a "light" detach (that only unsets the domain). With the domain set to `NULL`, looking up a JitInfo for a given `ip` will result into a crash, but it isn't even necessarily needed for the purpose of suspending a thread.

More details: Consider the following:
```
(lldb) c
error: Process is running.  Use 'process interrupt' to pause execution.
Process 12832 stopped
* thread mono#9, name = 'tid_a31f', queue = 'NSOperationQueue 0x8069b670 (QOS: UTILITY)', stop reason = breakpoint 1.1
    frame #0: 0x00222870 WatchWCSessionAppWatchOSExtension`debugger_interrupt_critical(info=0x81365400, user_data=0xb04dc718) at debugger-agent.c:2716:6
   2713         MonoDomain *domain = (MonoDomain *) mono_thread_info_get_suspend_state (info)->unwind_data [MONO_UNWIND_DATA_DOMAIN];
   2714         if (!domain) {
   2715                 /* not attached */
-> 2716                 ji = NULL;
   2717         } else {
   2718                 ji = mono_jit_info_table_find_internal ( domain, MONO_CONTEXT_GET_IP (&mono_thread_info_get_suspend_state (info)->ctx), TRUE, TRUE);
   2719         }
Target 0: (WatchWCSessionAppWatchOSExtension) stopped.
(lldb) bt
* thread mono#9, name = 'tid_a31f', queue = 'NSOperationQueue 0x8069b670 (QOS: UTILITY)', stop reason = breakpoint 1.1
  * frame #0: 0x00222870 WatchWCSessionAppWatchOSExtension`debugger_interrupt_critical(info=0x81365400, user_data=0xb04dc718) at debugger-agent.c:2716:6
    frame #1: 0x004e177b WatchWCSessionAppWatchOSExtension`mono_thread_info_safe_suspend_and_run(id=0xb0767000, interrupt_kernel=0, callback=(WatchWCSessionAppWatchOSExtension`debugger_interrupt_critical at debugger-agent.c:2708), user_data=0xb04dc718) at mono-threads.c:1358:19
    frame #2: 0x00222799 WatchWCSessionAppWatchOSExtension`notify_thread(key=0x03994508, value=0x81378c00, user_data=0x00000000) at debugger-agent.c:2747:2
    frame mono#3: 0x00355bd8 WatchWCSessionAppWatchOSExtension`mono_g_hash_table_foreach(hash=0x8007b4e0, func=(WatchWCSessionAppWatchOSExtension`notify_thread at debugger-agent.c:2733), user_data=0x00000000) at mono-hash.c:310:4
    frame mono#4: 0x0021e955 WatchWCSessionAppWatchOSExtension`suspend_vm at debugger-agent.c:2844:3
    frame mono#5: 0x00225ff0 WatchWCSessionAppWatchOSExtension`process_event(event=EVENT_KIND_THREAD_START, arg=0x039945d0, il_offset=0, ctx=0x00000000, events=0x805b28e0, suspend_policy=2) at debugger-agent.c:4012:3
    frame mono#6: 0x00227c7c WatchWCSessionAppWatchOSExtension`process_profiler_event(event=EVENT_KIND_THREAD_START, arg=0x039945d0) at debugger-agent.c:4072:2
    frame mono#7: 0x0021b174 WatchWCSessionAppWatchOSExtension`thread_startup(prof=0x00000000, tid=2957889536) at debugger-agent.c:4149:2
    frame mono#8: 0x0037912d WatchWCSessionAppWatchOSExtension`mono_profiler_raise_thread_started(tid=2957889536) at profiler-events.h:103:1
    frame mono#9: 0x003d53da WatchWCSessionAppWatchOSExtension`fire_attach_profiler_events(tid=0xb04dd000) at threads.c:1120:2
    frame mono#10: 0x003d4d83 WatchWCSessionAppWatchOSExtension`mono_thread_attach(domain=0x801750a0) at threads.c:1547:2
    frame mono#11: 0x003df1a1 WatchWCSessionAppWatchOSExtension`mono_threads_attach_coop_internal(domain=0x801750a0, cookie=0xb04dcc0c, stackdata=0xb04dcba8) at threads.c:6008:3
    frame mono#12: 0x003df287 WatchWCSessionAppWatchOSExtension`mono_threads_attach_coop(domain=0x00000000, dummy=0xb04dcc0c) at threads.c:6045:9
    frame mono#13: 0x005034b8 WatchWCSessionAppWatchOSExtension`::xamarin_switch_gchandle(self=0x80762c20, to_weak=false) at runtime.m:1805:2
    frame mono#14: 0x005065c1 WatchWCSessionAppWatchOSExtension`::xamarin_retain_trampoline(self=0x80762c20, sel="retain") at trampolines.m:693:2
    frame mono#15: 0x657ea520 libobjc.A.dylib`objc_retain + 64
    frame mono#16: 0x4b4d9caa WatchConnectivity`__66-[WCSession onqueue_handleDictionaryMessageRequest:withPairingID:]_block_invoke + 279
    frame mono#17: 0x453c7df7 Foundation`__NSBLOCKOPERATION_IS_CALLING_OUT_TO_A_BLOCK__ + 12
    frame mono#18: 0x453c7cf4 Foundation`-[NSBlockOperation main] + 88
    frame mono#19: 0x453cacee Foundation`__NSOPERATION_IS_INVOKING_MAIN__ + 27
    frame mono#20: 0x453c6ebd Foundation`-[NSOperation start] + 835
    frame mono#21: 0x453cb606 Foundation`__NSOPERATIONQUEUE_IS_STARTING_AN_OPERATION__ + 27
    frame mono#22: 0x453cb12e Foundation`__NSOQSchedule_f + 194
    frame mono#23: 0x453cb26e Foundation`____addOperations_block_invoke_4 + 20
    frame mono#24: 0x65de007b libdispatch.dylib`_dispatch_call_block_and_release + 15
    frame mono#25: 0x65de126f libdispatch.dylib`_dispatch_client_callout + 14
    frame mono#26: 0x65de3788 libdispatch.dylib`_dispatch_continuation_pop + 421
    frame mono#27: 0x65de2ee3 libdispatch.dylib`_dispatch_async_redirect_invoke + 818
    frame mono#28: 0x65df087d libdispatch.dylib`_dispatch_root_queue_drain + 354
    frame mono#29: 0x65df0ff3 libdispatch.dylib`_dispatch_worker_thread2 + 109
    frame mono#30: 0x66024fa0 libsystem_pthread.dylib`_pthread_wqthread + 208
    frame mono#31: 0x66024e44 libsystem_pthread.dylib`start_wqthread + 36
```

Going further, `info` is about this thread:
```
(lldb) p/x *(int *)(((char *) info->node.key) + 0xa0)
(int) $2 = 0x01243f93
(lldb) thread list
Process 12832 stopped
  thread #1: tid = 0x1243ee1, 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10, name = 'tid_303', queue = 'com.apple.main-thread'
  thread #2: tid = 0x1243ee6, 0x65f816e2 libsystem_kernel.dylib`__recvfrom + 10
  thread mono#3: tid = 0x1243ee7, 0x65f81aea libsystem_kernel.dylib`__psynch_cvwait + 10, name = 'SGen worker'
  thread mono#4: tid = 0x1243ee9, 0x65f7e3d2 libsystem_kernel.dylib`semaphore_wait_trap + 10, name = 'Finalizer'
  thread mono#5: tid = 0x1243eea, 0x65f816e2 libsystem_kernel.dylib`__recvfrom + 10, name = 'Debugger agent'
  thread mono#6: tid = 0x1243f1d, 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10, name = 'com.apple.uikit.eventfetch-thread'
  thread mono#8: tid = 0x1243f93, 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10, name = 'tid_6d0f', queue = 'NSOperationQueue 0x8069b300 (QOS: UTILITY)'
* thread mono#9: tid = 0x12443a9, 0x00222870 WatchWCSessionAppWatchOSExtension`debugger_interrupt_critical(info=0x81365400, user_data=0xb04dc718) at debugger-agent.c:2716:6, name = 'tid_a31f', queue = 'NSOperationQueue 0x8069b670 (QOS: UTILITY)', stop reason = breakpoint 1.1
  thread mono#10: tid = 0x1244581, 0x65f7fd32 libsystem_kernel.dylib`__workq_kernreturn + 10
(lldb) thread select 8
* thread mono#8, name = 'tid_6d0f', queue = 'NSOperationQueue 0x8069b300 (QOS: UTILITY)'
    frame #0: 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10
libsystem_kernel.dylib`mach_msg_trap:
->  0x65f7e396 <+10>: retl
    0x65f7e397 <+11>: nop

libsystem_kernel.dylib`mach_msg_overwrite_trap:
    0x65f7e398 <+0>:  movl   $0xffffffe0, %eax         ; imm = 0xFFFFFFE0
    0x65f7e39d <+5>:  calll  0x65f85f44                ; _sysenter_trap
(lldb) bt
* thread mono#8, name = 'tid_6d0f', queue = 'NSOperationQueue 0x8069b300 (QOS: UTILITY)'
  * frame #0: 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10
    frame #1: 0x65f7e8ff libsystem_kernel.dylib`mach_msg + 47
    frame #2: 0x66079679 libxpc.dylib`_xpc_send_serializer + 104
    frame mono#3: 0x660794da libxpc.dylib`_xpc_pipe_simpleroutine + 80
    frame mono#4: 0x66079852 libxpc.dylib`xpc_pipe_simpleroutine + 43
    frame mono#5: 0x66043a8f libsystem_trace.dylib`___os_activity_stream_reflect_block_invoke_2 + 30
    frame mono#6: 0x65de126f libdispatch.dylib`_dispatch_client_callout + 14
    frame mono#7: 0x65de3d71 libdispatch.dylib`_dispatch_block_invoke_direct + 257
    frame mono#8: 0x65de3c62 libdispatch.dylib`dispatch_block_perform + 112
    frame mono#9: 0x6604349a libsystem_trace.dylib`_os_activity_stream_reflect + 725
    frame mono#10: 0x6604ef19 libsystem_trace.dylib`_os_log_impl_stream + 468
    frame mono#11: 0x6604e44d libsystem_trace.dylib`_os_log_impl_flatten_and_send + 6410
    frame mono#12: 0x6604cb3b libsystem_trace.dylib`_os_log + 137
    frame mono#13: 0x6604f4aa libsystem_trace.dylib`_os_log_impl + 31
    frame mono#14: 0x4b4eb4e9 WatchConnectivity`WCSerializePayloadDictionary + 393
    frame mono#15: 0x4b4d7c4d WatchConnectivity`-[WCSession onqueue_sendResponseDictionary:identifier:] + 195
    frame mono#16: 0x4b4da435 WatchConnectivity`__66-[WCSession onqueue_handleDictionaryMessageRequest:withPairingID:]_block_invoke.411 + 35
    frame mono#17: 0x453c7df7 Foundation`__NSBLOCKOPERATION_IS_CALLING_OUT_TO_A_BLOCK__ + 12
    frame mono#18: 0x453c7cf4 Foundation`-[NSBlockOperation main] + 88
    frame mono#19: 0x453cacee Foundation`__NSOPERATION_IS_INVOKING_MAIN__ + 27
    frame mono#20: 0x453c6ebd Foundation`-[NSOperation start] + 835
    frame mono#21: 0x453cb606 Foundation`__NSOPERATIONQUEUE_IS_STARTING_AN_OPERATION__ + 27
    frame mono#22: 0x453cb12e Foundation`__NSOQSchedule_f + 194
    frame mono#23: 0x453cb067 Foundation`____addOperations_block_invoke_2 + 20
    frame mono#24: 0x65dedf49 libdispatch.dylib`_dispatch_block_async_invoke2 + 77
    frame mono#25: 0x65de4461 libdispatch.dylib`_dispatch_block_async_invoke_and_release + 17
    frame mono#26: 0x65de126f libdispatch.dylib`_dispatch_client_callout + 14
    frame mono#27: 0x65de3788 libdispatch.dylib`_dispatch_continuation_pop + 421
    frame mono#28: 0x65de2ee3 libdispatch.dylib`_dispatch_async_redirect_invoke + 818
    frame mono#29: 0x65df087d libdispatch.dylib`_dispatch_root_queue_drain + 354
    frame mono#30: 0x65df0ff3 libdispatch.dylib`_dispatch_worker_thread2 + 109
    frame mono#31: 0x66024fa0 libsystem_pthread.dylib`_pthread_wqthread + 208
    frame mono#32: 0x66024e44 libsystem_pthread.dylib`start_wqthread + 36
```
which is a thread in a "light" detach state (aka. coop detach), where we only unset the domain:
https://github.com/mono/mono/blob/4cefdcb7ce2d939ee78fb45d1b4913eb3bc064fd/mono/metadata/threads.c#L6084-L6111

Fixes mono#17926
lewurm added a commit that referenced this pull request Dec 10, 2019
@lewurm
[debugger] skip suspend for unattached threads (#18105)
80b1e10 
When the debugger tries to suspend all the VM threads, it can happen with cooperative-suspend that it tries to suspend a thread that has previously been attached, but then did a "light" detach (that only unsets the domain). With the domain set to `NULL`, looking up a JitInfo for a given `ip` will result into a crash, but it isn't even necessarily needed for the purpose of suspending a thread.

More details: Consider the following:
```
(lldb) c
error: Process is running.  Use 'process interrupt' to pause execution.
Process 12832 stopped
* thread #9, name = 'tid_a31f', queue = 'NSOperationQueue 0x8069b670 (QOS: UTILITY)', stop reason = breakpoint 1.1
    frame #0: 0x00222870 WatchWCSessionAppWatchOSExtension`debugger_interrupt_critical(info=0x81365400, user_data=0xb04dc718) at debugger-agent.c:2716:6
   2713         MonoDomain *domain = (MonoDomain *) mono_thread_info_get_suspend_state (info)->unwind_data [MONO_UNWIND_DATA_DOMAIN];
   2714         if (!domain) {
   2715                 /* not attached */
-> 2716                 ji = NULL;
   2717         } else {
   2718                 ji = mono_jit_info_table_find_internal ( domain, MONO_CONTEXT_GET_IP (&mono_thread_info_get_suspend_state (info)->ctx), TRUE, TRUE);
   2719         }
Target 0: (WatchWCSessionAppWatchOSExtension) stopped.
(lldb) bt
* thread #9, name = 'tid_a31f', queue = 'NSOperationQueue 0x8069b670 (QOS: UTILITY)', stop reason = breakpoint 1.1
  * frame #0: 0x00222870 WatchWCSessionAppWatchOSExtension`debugger_interrupt_critical(info=0x81365400, user_data=0xb04dc718) at debugger-agent.c:2716:6
    frame #1: 0x004e177b WatchWCSessionAppWatchOSExtension`mono_thread_info_safe_suspend_and_run(id=0xb0767000, interrupt_kernel=0, callback=(WatchWCSessionAppWatchOSExtension`debugger_interrupt_critical at debugger-agent.c:2708), user_data=0xb04dc718) at mono-threads.c:1358:19
    frame #2: 0x00222799 WatchWCSessionAppWatchOSExtension`notify_thread(key=0x03994508, value=0x81378c00, user_data=0x00000000) at debugger-agent.c:2747:2
    frame #3: 0x00355bd8 WatchWCSessionAppWatchOSExtension`mono_g_hash_table_foreach(hash=0x8007b4e0, func=(WatchWCSessionAppWatchOSExtension`notify_thread at debugger-agent.c:2733), user_data=0x00000000) at mono-hash.c:310:4
    frame #4: 0x0021e955 WatchWCSessionAppWatchOSExtension`suspend_vm at debugger-agent.c:2844:3
    frame #5: 0x00225ff0 WatchWCSessionAppWatchOSExtension`process_event(event=EVENT_KIND_THREAD_START, arg=0x039945d0, il_offset=0, ctx=0x00000000, events=0x805b28e0, suspend_policy=2) at debugger-agent.c:4012:3
    frame #6: 0x00227c7c WatchWCSessionAppWatchOSExtension`process_profiler_event(event=EVENT_KIND_THREAD_START, arg=0x039945d0) at debugger-agent.c:4072:2
    frame #7: 0x0021b174 WatchWCSessionAppWatchOSExtension`thread_startup(prof=0x00000000, tid=2957889536) at debugger-agent.c:4149:2
    frame #8: 0x0037912d WatchWCSessionAppWatchOSExtension`mono_profiler_raise_thread_started(tid=2957889536) at profiler-events.h:103:1
    frame #9: 0x003d53da WatchWCSessionAppWatchOSExtension`fire_attach_profiler_events(tid=0xb04dd000) at threads.c:1120:2
    frame #10: 0x003d4d83 WatchWCSessionAppWatchOSExtension`mono_thread_attach(domain=0x801750a0) at threads.c:1547:2
    frame #11: 0x003df1a1 WatchWCSessionAppWatchOSExtension`mono_threads_attach_coop_internal(domain=0x801750a0, cookie=0xb04dcc0c, stackdata=0xb04dcba8) at threads.c:6008:3
    frame #12: 0x003df287 WatchWCSessionAppWatchOSExtension`mono_threads_attach_coop(domain=0x00000000, dummy=0xb04dcc0c) at threads.c:6045:9
    frame #13: 0x005034b8 WatchWCSessionAppWatchOSExtension`::xamarin_switch_gchandle(self=0x80762c20, to_weak=false) at runtime.m:1805:2
    frame #14: 0x005065c1 WatchWCSessionAppWatchOSExtension`::xamarin_retain_trampoline(self=0x80762c20, sel="retain") at trampolines.m:693:2
    frame #15: 0x657ea520 libobjc.A.dylib`objc_retain + 64
    frame #16: 0x4b4d9caa WatchConnectivity`__66-[WCSession onqueue_handleDictionaryMessageRequest:withPairingID:]_block_invoke + 279
    frame #17: 0x453c7df7 Foundation`__NSBLOCKOPERATION_IS_CALLING_OUT_TO_A_BLOCK__ + 12
    frame #18: 0x453c7cf4 Foundation`-[NSBlockOperation main] + 88
    frame #19: 0x453cacee Foundation`__NSOPERATION_IS_INVOKING_MAIN__ + 27
    frame #20: 0x453c6ebd Foundation`-[NSOperation start] + 835
    frame #21: 0x453cb606 Foundation`__NSOPERATIONQUEUE_IS_STARTING_AN_OPERATION__ + 27
    frame #22: 0x453cb12e Foundation`__NSOQSchedule_f + 194
    frame #23: 0x453cb26e Foundation`____addOperations_block_invoke_4 + 20
    frame #24: 0x65de007b libdispatch.dylib`_dispatch_call_block_and_release + 15
    frame #25: 0x65de126f libdispatch.dylib`_dispatch_client_callout + 14
    frame #26: 0x65de3788 libdispatch.dylib`_dispatch_continuation_pop + 421
    frame #27: 0x65de2ee3 libdispatch.dylib`_dispatch_async_redirect_invoke + 818
    frame #28: 0x65df087d libdispatch.dylib`_dispatch_root_queue_drain + 354
    frame #29: 0x65df0ff3 libdispatch.dylib`_dispatch_worker_thread2 + 109
    frame #30: 0x66024fa0 libsystem_pthread.dylib`_pthread_wqthread + 208
    frame #31: 0x66024e44 libsystem_pthread.dylib`start_wqthread + 36
```

Going further, `info` is about this thread:
```
(lldb) p/x *(int *)(((char *) info->node.key) + 0xa0)
(int) $2 = 0x01243f93
(lldb) thread list
Process 12832 stopped
  thread #1: tid = 0x1243ee1, 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10, name = 'tid_303', queue = 'com.apple.main-thread'
  thread #2: tid = 0x1243ee6, 0x65f816e2 libsystem_kernel.dylib`__recvfrom + 10
  thread #3: tid = 0x1243ee7, 0x65f81aea libsystem_kernel.dylib`__psynch_cvwait + 10, name = 'SGen worker'
  thread #4: tid = 0x1243ee9, 0x65f7e3d2 libsystem_kernel.dylib`semaphore_wait_trap + 10, name = 'Finalizer'
  thread #5: tid = 0x1243eea, 0x65f816e2 libsystem_kernel.dylib`__recvfrom + 10, name = 'Debugger agent'
  thread #6: tid = 0x1243f1d, 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10, name = 'com.apple.uikit.eventfetch-thread'
  thread #8: tid = 0x1243f93, 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10, name = 'tid_6d0f', queue = 'NSOperationQueue 0x8069b300 (QOS: UTILITY)'
* thread #9: tid = 0x12443a9, 0x00222870 WatchWCSessionAppWatchOSExtension`debugger_interrupt_critical(info=0x81365400, user_data=0xb04dc718) at debugger-agent.c:2716:6, name = 'tid_a31f', queue = 'NSOperationQueue 0x8069b670 (QOS: UTILITY)', stop reason = breakpoint 1.1
  thread #10: tid = 0x1244581, 0x65f7fd32 libsystem_kernel.dylib`__workq_kernreturn + 10
(lldb) thread select 8
* thread #8, name = 'tid_6d0f', queue = 'NSOperationQueue 0x8069b300 (QOS: UTILITY)'
    frame #0: 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10
libsystem_kernel.dylib`mach_msg_trap:
->  0x65f7e396 <+10>: retl
    0x65f7e397 <+11>: nop

libsystem_kernel.dylib`mach_msg_overwrite_trap:
    0x65f7e398 <+0>:  movl   $0xffffffe0, %eax         ; imm = 0xFFFFFFE0
    0x65f7e39d <+5>:  calll  0x65f85f44                ; _sysenter_trap
(lldb) bt
* thread #8, name = 'tid_6d0f', queue = 'NSOperationQueue 0x8069b300 (QOS: UTILITY)'
  * frame #0: 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10
    frame #1: 0x65f7e8ff libsystem_kernel.dylib`mach_msg + 47
    frame #2: 0x66079679 libxpc.dylib`_xpc_send_serializer + 104
    frame #3: 0x660794da libxpc.dylib`_xpc_pipe_simpleroutine + 80
    frame #4: 0x66079852 libxpc.dylib`xpc_pipe_simpleroutine + 43
    frame #5: 0x66043a8f libsystem_trace.dylib`___os_activity_stream_reflect_block_invoke_2 + 30
    frame #6: 0x65de126f libdispatch.dylib`_dispatch_client_callout + 14
    frame #7: 0x65de3d71 libdispatch.dylib`_dispatch_block_invoke_direct + 257
    frame #8: 0x65de3c62 libdispatch.dylib`dispatch_block_perform + 112
    frame #9: 0x6604349a libsystem_trace.dylib`_os_activity_stream_reflect + 725
    frame #10: 0x6604ef19 libsystem_trace.dylib`_os_log_impl_stream + 468
    frame #11: 0x6604e44d libsystem_trace.dylib`_os_log_impl_flatten_and_send + 6410
    frame #12: 0x6604cb3b libsystem_trace.dylib`_os_log + 137
    frame #13: 0x6604f4aa libsystem_trace.dylib`_os_log_impl + 31
    frame #14: 0x4b4eb4e9 WatchConnectivity`WCSerializePayloadDictionary + 393
    frame #15: 0x4b4d7c4d WatchConnectivity`-[WCSession onqueue_sendResponseDictionary:identifier:] + 195
    frame #16: 0x4b4da435 WatchConnectivity`__66-[WCSession onqueue_handleDictionaryMessageRequest:withPairingID:]_block_invoke.411 + 35
    frame #17: 0x453c7df7 Foundation`__NSBLOCKOPERATION_IS_CALLING_OUT_TO_A_BLOCK__ + 12
    frame #18: 0x453c7cf4 Foundation`-[NSBlockOperation main] + 88
    frame #19: 0x453cacee Foundation`__NSOPERATION_IS_INVOKING_MAIN__ + 27
    frame #20: 0x453c6ebd Foundation`-[NSOperation start] + 835
    frame #21: 0x453cb606 Foundation`__NSOPERATIONQUEUE_IS_STARTING_AN_OPERATION__ + 27
    frame #22: 0x453cb12e Foundation`__NSOQSchedule_f + 194
    frame #23: 0x453cb067 Foundation`____addOperations_block_invoke_2 + 20
    frame #24: 0x65dedf49 libdispatch.dylib`_dispatch_block_async_invoke2 + 77
    frame #25: 0x65de4461 libdispatch.dylib`_dispatch_block_async_invoke_and_release + 17
    frame #26: 0x65de126f libdispatch.dylib`_dispatch_client_callout + 14
    frame #27: 0x65de3788 libdispatch.dylib`_dispatch_continuation_pop + 421
    frame #28: 0x65de2ee3 libdispatch.dylib`_dispatch_async_redirect_invoke + 818
    frame #29: 0x65df087d libdispatch.dylib`_dispatch_root_queue_drain + 354
    frame #30: 0x65df0ff3 libdispatch.dylib`_dispatch_worker_thread2 + 109
    frame #31: 0x66024fa0 libsystem_pthread.dylib`_pthread_wqthread + 208
    frame #32: 0x66024e44 libsystem_pthread.dylib`start_wqthread + 36
```
which is a thread in a "light" detach state (aka. coop detach), where we only unset the domain:
https://github.com/mono/mono/blob/4cefdcb7ce2d939ee78fb45d1b4913eb3bc064fd/mono/metadata/threads.c#L6084-L6111

Fixes #17926
monojenkins pushed a commit to monojenkins/mono that referenced this pull request Dec 10, 2019
@lewurm @monojenkins
[debugger] skip suspend for unattached threads
4aff15e 
When the debugger tries to suspend all the VM threads, it can happen with cooperative-suspend that it tries to suspend a thread that has previously been attached, but then did a "light" detach (that only unsets the domain). With the domain set to `NULL`, looking up a JitInfo for a given `ip` will result into a crash, but it isn't even necessarily needed for the purpose of suspending a thread.

More details: Consider the following:
```
(lldb) c
error: Process is running.  Use 'process interrupt' to pause execution.
Process 12832 stopped
* thread mono#9, name = 'tid_a31f', queue = 'NSOperationQueue 0x8069b670 (QOS: UTILITY)', stop reason = breakpoint 1.1
    frame #0: 0x00222870 WatchWCSessionAppWatchOSExtension`debugger_interrupt_critical(info=0x81365400, user_data=0xb04dc718) at debugger-agent.c:2716:6
   2713         MonoDomain *domain = (MonoDomain *) mono_thread_info_get_suspend_state (info)->unwind_data [MONO_UNWIND_DATA_DOMAIN];
   2714         if (!domain) {
   2715                 /* not attached */
-> 2716                 ji = NULL;
   2717         } else {
   2718                 ji = mono_jit_info_table_find_internal ( domain, MONO_CONTEXT_GET_IP (&mono_thread_info_get_suspend_state (info)->ctx), TRUE, TRUE);
   2719         }
Target 0: (WatchWCSessionAppWatchOSExtension) stopped.
(lldb) bt
* thread mono#9, name = 'tid_a31f', queue = 'NSOperationQueue 0x8069b670 (QOS: UTILITY)', stop reason = breakpoint 1.1
  * frame #0: 0x00222870 WatchWCSessionAppWatchOSExtension`debugger_interrupt_critical(info=0x81365400, user_data=0xb04dc718) at debugger-agent.c:2716:6
    frame mono#1: 0x004e177b WatchWCSessionAppWatchOSExtension`mono_thread_info_safe_suspend_and_run(id=0xb0767000, interrupt_kernel=0, callback=(WatchWCSessionAppWatchOSExtension`debugger_interrupt_critical at debugger-agent.c:2708), user_data=0xb04dc718) at mono-threads.c:1358:19
    frame mono#2: 0x00222799 WatchWCSessionAppWatchOSExtension`notify_thread(key=0x03994508, value=0x81378c00, user_data=0x00000000) at debugger-agent.c:2747:2
    frame mono#3: 0x00355bd8 WatchWCSessionAppWatchOSExtension`mono_g_hash_table_foreach(hash=0x8007b4e0, func=(WatchWCSessionAppWatchOSExtension`notify_thread at debugger-agent.c:2733), user_data=0x00000000) at mono-hash.c:310:4
    frame mono#4: 0x0021e955 WatchWCSessionAppWatchOSExtension`suspend_vm at debugger-agent.c:2844:3
    frame mono#5: 0x00225ff0 WatchWCSessionAppWatchOSExtension`process_event(event=EVENT_KIND_THREAD_START, arg=0x039945d0, il_offset=0, ctx=0x00000000, events=0x805b28e0, suspend_policy=2) at debugger-agent.c:4012:3
    frame mono#6: 0x00227c7c WatchWCSessionAppWatchOSExtension`process_profiler_event(event=EVENT_KIND_THREAD_START, arg=0x039945d0) at debugger-agent.c:4072:2
    frame mono#7: 0x0021b174 WatchWCSessionAppWatchOSExtension`thread_startup(prof=0x00000000, tid=2957889536) at debugger-agent.c:4149:2
    frame mono#8: 0x0037912d WatchWCSessionAppWatchOSExtension`mono_profiler_raise_thread_started(tid=2957889536) at profiler-events.h:103:1
    frame mono#9: 0x003d53da WatchWCSessionAppWatchOSExtension`fire_attach_profiler_events(tid=0xb04dd000) at threads.c:1120:2
    frame mono#10: 0x003d4d83 WatchWCSessionAppWatchOSExtension`mono_thread_attach(domain=0x801750a0) at threads.c:1547:2
    frame mono#11: 0x003df1a1 WatchWCSessionAppWatchOSExtension`mono_threads_attach_coop_internal(domain=0x801750a0, cookie=0xb04dcc0c, stackdata=0xb04dcba8) at threads.c:6008:3
    frame mono#12: 0x003df287 WatchWCSessionAppWatchOSExtension`mono_threads_attach_coop(domain=0x00000000, dummy=0xb04dcc0c) at threads.c:6045:9
    frame mono#13: 0x005034b8 WatchWCSessionAppWatchOSExtension`::xamarin_switch_gchandle(self=0x80762c20, to_weak=false) at runtime.m:1805:2
    frame mono#14: 0x005065c1 WatchWCSessionAppWatchOSExtension`::xamarin_retain_trampoline(self=0x80762c20, sel="retain") at trampolines.m:693:2
    frame mono#15: 0x657ea520 libobjc.A.dylib`objc_retain + 64
    frame mono#16: 0x4b4d9caa WatchConnectivity`__66-[WCSession onqueue_handleDictionaryMessageRequest:withPairingID:]_block_invoke + 279
    frame mono#17: 0x453c7df7 Foundation`__NSBLOCKOPERATION_IS_CALLING_OUT_TO_A_BLOCK__ + 12
    frame mono#18: 0x453c7cf4 Foundation`-[NSBlockOperation main] + 88
    frame mono#19: 0x453cacee Foundation`__NSOPERATION_IS_INVOKING_MAIN__ + 27
    frame mono#20: 0x453c6ebd Foundation`-[NSOperation start] + 835
    frame mono#21: 0x453cb606 Foundation`__NSOPERATIONQUEUE_IS_STARTING_AN_OPERATION__ + 27
    frame mono#22: 0x453cb12e Foundation`__NSOQSchedule_f + 194
    frame mono#23: 0x453cb26e Foundation`____addOperations_block_invoke_4 + 20
    frame mono#24: 0x65de007b libdispatch.dylib`_dispatch_call_block_and_release + 15
    frame mono#25: 0x65de126f libdispatch.dylib`_dispatch_client_callout + 14
    frame mono#26: 0x65de3788 libdispatch.dylib`_dispatch_continuation_pop + 421
    frame mono#27: 0x65de2ee3 libdispatch.dylib`_dispatch_async_redirect_invoke + 818
    frame mono#28: 0x65df087d libdispatch.dylib`_dispatch_root_queue_drain + 354
    frame mono#29: 0x65df0ff3 libdispatch.dylib`_dispatch_worker_thread2 + 109
    frame mono#30: 0x66024fa0 libsystem_pthread.dylib`_pthread_wqthread + 208
    frame mono#31: 0x66024e44 libsystem_pthread.dylib`start_wqthread + 36
```

Going further, `info` is about this thread:
```
(lldb) p/x *(int *)(((char *) info->node.key) + 0xa0)
(int) $2 = 0x01243f93
(lldb) thread list
Process 12832 stopped
  thread mono#1: tid = 0x1243ee1, 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10, name = 'tid_303', queue = 'com.apple.main-thread'
  thread mono#2: tid = 0x1243ee6, 0x65f816e2 libsystem_kernel.dylib`__recvfrom + 10
  thread mono#3: tid = 0x1243ee7, 0x65f81aea libsystem_kernel.dylib`__psynch_cvwait + 10, name = 'SGen worker'
  thread mono#4: tid = 0x1243ee9, 0x65f7e3d2 libsystem_kernel.dylib`semaphore_wait_trap + 10, name = 'Finalizer'
  thread mono#5: tid = 0x1243eea, 0x65f816e2 libsystem_kernel.dylib`__recvfrom + 10, name = 'Debugger agent'
  thread mono#6: tid = 0x1243f1d, 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10, name = 'com.apple.uikit.eventfetch-thread'
  thread mono#8: tid = 0x1243f93, 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10, name = 'tid_6d0f', queue = 'NSOperationQueue 0x8069b300 (QOS: UTILITY)'
* thread mono#9: tid = 0x12443a9, 0x00222870 WatchWCSessionAppWatchOSExtension`debugger_interrupt_critical(info=0x81365400, user_data=0xb04dc718) at debugger-agent.c:2716:6, name = 'tid_a31f', queue = 'NSOperationQueue 0x8069b670 (QOS: UTILITY)', stop reason = breakpoint 1.1
  thread mono#10: tid = 0x1244581, 0x65f7fd32 libsystem_kernel.dylib`__workq_kernreturn + 10
(lldb) thread select 8
* thread mono#8, name = 'tid_6d0f', queue = 'NSOperationQueue 0x8069b300 (QOS: UTILITY)'
    frame #0: 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10
libsystem_kernel.dylib`mach_msg_trap:
->  0x65f7e396 <+10>: retl
    0x65f7e397 <+11>: nop

libsystem_kernel.dylib`mach_msg_overwrite_trap:
    0x65f7e398 <+0>:  movl   $0xffffffe0, %eax         ; imm = 0xFFFFFFE0
    0x65f7e39d <+5>:  calll  0x65f85f44                ; _sysenter_trap
(lldb) bt
* thread mono#8, name = 'tid_6d0f', queue = 'NSOperationQueue 0x8069b300 (QOS: UTILITY)'
  * frame #0: 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10
    frame mono#1: 0x65f7e8ff libsystem_kernel.dylib`mach_msg + 47
    frame mono#2: 0x66079679 libxpc.dylib`_xpc_send_serializer + 104
    frame mono#3: 0x660794da libxpc.dylib`_xpc_pipe_simpleroutine + 80
    frame mono#4: 0x66079852 libxpc.dylib`xpc_pipe_simpleroutine + 43
    frame mono#5: 0x66043a8f libsystem_trace.dylib`___os_activity_stream_reflect_block_invoke_2 + 30
    frame mono#6: 0x65de126f libdispatch.dylib`_dispatch_client_callout + 14
    frame mono#7: 0x65de3d71 libdispatch.dylib`_dispatch_block_invoke_direct + 257
    frame mono#8: 0x65de3c62 libdispatch.dylib`dispatch_block_perform + 112
    frame mono#9: 0x6604349a libsystem_trace.dylib`_os_activity_stream_reflect + 725
    frame mono#10: 0x6604ef19 libsystem_trace.dylib`_os_log_impl_stream + 468
    frame mono#11: 0x6604e44d libsystem_trace.dylib`_os_log_impl_flatten_and_send + 6410
    frame mono#12: 0x6604cb3b libsystem_trace.dylib`_os_log + 137
    frame mono#13: 0x6604f4aa libsystem_trace.dylib`_os_log_impl + 31
    frame mono#14: 0x4b4eb4e9 WatchConnectivity`WCSerializePayloadDictionary + 393
    frame mono#15: 0x4b4d7c4d WatchConnectivity`-[WCSession onqueue_sendResponseDictionary:identifier:] + 195
    frame mono#16: 0x4b4da435 WatchConnectivity`__66-[WCSession onqueue_handleDictionaryMessageRequest:withPairingID:]_block_invoke.411 + 35
    frame mono#17: 0x453c7df7 Foundation`__NSBLOCKOPERATION_IS_CALLING_OUT_TO_A_BLOCK__ + 12
    frame mono#18: 0x453c7cf4 Foundation`-[NSBlockOperation main] + 88
    frame mono#19: 0x453cacee Foundation`__NSOPERATION_IS_INVOKING_MAIN__ + 27
    frame mono#20: 0x453c6ebd Foundation`-[NSOperation start] + 835
    frame mono#21: 0x453cb606 Foundation`__NSOPERATIONQUEUE_IS_STARTING_AN_OPERATION__ + 27
    frame mono#22: 0x453cb12e Foundation`__NSOQSchedule_f + 194
    frame mono#23: 0x453cb067 Foundation`____addOperations_block_invoke_2 + 20
    frame mono#24: 0x65dedf49 libdispatch.dylib`_dispatch_block_async_invoke2 + 77
    frame mono#25: 0x65de4461 libdispatch.dylib`_dispatch_block_async_invoke_and_release + 17
    frame mono#26: 0x65de126f libdispatch.dylib`_dispatch_client_callout + 14
    frame mono#27: 0x65de3788 libdispatch.dylib`_dispatch_continuation_pop + 421
    frame mono#28: 0x65de2ee3 libdispatch.dylib`_dispatch_async_redirect_invoke + 818
    frame mono#29: 0x65df087d libdispatch.dylib`_dispatch_root_queue_drain + 354
    frame mono#30: 0x65df0ff3 libdispatch.dylib`_dispatch_worker_thread2 + 109
    frame mono#31: 0x66024fa0 libsystem_pthread.dylib`_pthread_wqthread + 208
    frame mono#32: 0x66024e44 libsystem_pthread.dylib`start_wqthread + 36
```
which is a thread in a "light" detach state (aka. coop detach), where we only unset the domain:
https://github.com/mono/mono/blob/4cefdcb7ce2d939ee78fb45d1b4913eb3bc064fd/mono/metadata/threads.c#L6084-L6111

Fixes mono#17926
monojenkins pushed a commit to monojenkins/mono that referenced this pull request Dec 10, 2019
@lewurm @monojenkins
[debugger] skip suspend for unattached threads
b379c7b 
When the debugger tries to suspend all the VM threads, it can happen with cooperative-suspend that it tries to suspend a thread that has previously been attached, but then did a "light" detach (that only unsets the domain). With the domain set to `NULL`, looking up a JitInfo for a given `ip` will result into a crash, but it isn't even necessarily needed for the purpose of suspending a thread.

More details: Consider the following:
```
(lldb) c
error: Process is running.  Use 'process interrupt' to pause execution.
Process 12832 stopped
* thread mono#9, name = 'tid_a31f', queue = 'NSOperationQueue 0x8069b670 (QOS: UTILITY)', stop reason = breakpoint 1.1
    frame #0: 0x00222870 WatchWCSessionAppWatchOSExtension`debugger_interrupt_critical(info=0x81365400, user_data=0xb04dc718) at debugger-agent.c:2716:6
   2713         MonoDomain *domain = (MonoDomain *) mono_thread_info_get_suspend_state (info)->unwind_data [MONO_UNWIND_DATA_DOMAIN];
   2714         if (!domain) {
   2715                 /* not attached */
-> 2716                 ji = NULL;
   2717         } else {
   2718                 ji = mono_jit_info_table_find_internal ( domain, MONO_CONTEXT_GET_IP (&mono_thread_info_get_suspend_state (info)->ctx), TRUE, TRUE);
   2719         }
Target 0: (WatchWCSessionAppWatchOSExtension) stopped.
(lldb) bt
* thread mono#9, name = 'tid_a31f', queue = 'NSOperationQueue 0x8069b670 (QOS: UTILITY)', stop reason = breakpoint 1.1
  * frame #0: 0x00222870 WatchWCSessionAppWatchOSExtension`debugger_interrupt_critical(info=0x81365400, user_data=0xb04dc718) at debugger-agent.c:2716:6
    frame mono#1: 0x004e177b WatchWCSessionAppWatchOSExtension`mono_thread_info_safe_suspend_and_run(id=0xb0767000, interrupt_kernel=0, callback=(WatchWCSessionAppWatchOSExtension`debugger_interrupt_critical at debugger-agent.c:2708), user_data=0xb04dc718) at mono-threads.c:1358:19
    frame mono#2: 0x00222799 WatchWCSessionAppWatchOSExtension`notify_thread(key=0x03994508, value=0x81378c00, user_data=0x00000000) at debugger-agent.c:2747:2
    frame mono#3: 0x00355bd8 WatchWCSessionAppWatchOSExtension`mono_g_hash_table_foreach(hash=0x8007b4e0, func=(WatchWCSessionAppWatchOSExtension`notify_thread at debugger-agent.c:2733), user_data=0x00000000) at mono-hash.c:310:4
    frame mono#4: 0x0021e955 WatchWCSessionAppWatchOSExtension`suspend_vm at debugger-agent.c:2844:3
    frame mono#5: 0x00225ff0 WatchWCSessionAppWatchOSExtension`process_event(event=EVENT_KIND_THREAD_START, arg=0x039945d0, il_offset=0, ctx=0x00000000, events=0x805b28e0, suspend_policy=2) at debugger-agent.c:4012:3
    frame mono#6: 0x00227c7c WatchWCSessionAppWatchOSExtension`process_profiler_event(event=EVENT_KIND_THREAD_START, arg=0x039945d0) at debugger-agent.c:4072:2
    frame mono#7: 0x0021b174 WatchWCSessionAppWatchOSExtension`thread_startup(prof=0x00000000, tid=2957889536) at debugger-agent.c:4149:2
    frame mono#8: 0x0037912d WatchWCSessionAppWatchOSExtension`mono_profiler_raise_thread_started(tid=2957889536) at profiler-events.h:103:1
    frame mono#9: 0x003d53da WatchWCSessionAppWatchOSExtension`fire_attach_profiler_events(tid=0xb04dd000) at threads.c:1120:2
    frame mono#10: 0x003d4d83 WatchWCSessionAppWatchOSExtension`mono_thread_attach(domain=0x801750a0) at threads.c:1547:2
    frame mono#11: 0x003df1a1 WatchWCSessionAppWatchOSExtension`mono_threads_attach_coop_internal(domain=0x801750a0, cookie=0xb04dcc0c, stackdata=0xb04dcba8) at threads.c:6008:3
    frame mono#12: 0x003df287 WatchWCSessionAppWatchOSExtension`mono_threads_attach_coop(domain=0x00000000, dummy=0xb04dcc0c) at threads.c:6045:9
    frame mono#13: 0x005034b8 WatchWCSessionAppWatchOSExtension`::xamarin_switch_gchandle(self=0x80762c20, to_weak=false) at runtime.m:1805:2
    frame mono#14: 0x005065c1 WatchWCSessionAppWatchOSExtension`::xamarin_retain_trampoline(self=0x80762c20, sel="retain") at trampolines.m:693:2
    frame mono#15: 0x657ea520 libobjc.A.dylib`objc_retain + 64
    frame mono#16: 0x4b4d9caa WatchConnectivity`__66-[WCSession onqueue_handleDictionaryMessageRequest:withPairingID:]_block_invoke + 279
    frame mono#17: 0x453c7df7 Foundation`__NSBLOCKOPERATION_IS_CALLING_OUT_TO_A_BLOCK__ + 12
    frame mono#18: 0x453c7cf4 Foundation`-[NSBlockOperation main] + 88
    frame mono#19: 0x453cacee Foundation`__NSOPERATION_IS_INVOKING_MAIN__ + 27
    frame mono#20: 0x453c6ebd Foundation`-[NSOperation start] + 835
    frame mono#21: 0x453cb606 Foundation`__NSOPERATIONQUEUE_IS_STARTING_AN_OPERATION__ + 27
    frame mono#22: 0x453cb12e Foundation`__NSOQSchedule_f + 194
    frame mono#23: 0x453cb26e Foundation`____addOperations_block_invoke_4 + 20
    frame mono#24: 0x65de007b libdispatch.dylib`_dispatch_call_block_and_release + 15
    frame mono#25: 0x65de126f libdispatch.dylib`_dispatch_client_callout + 14
    frame mono#26: 0x65de3788 libdispatch.dylib`_dispatch_continuation_pop + 421
    frame mono#27: 0x65de2ee3 libdispatch.dylib`_dispatch_async_redirect_invoke + 818
    frame mono#28: 0x65df087d libdispatch.dylib`_dispatch_root_queue_drain + 354
    frame mono#29: 0x65df0ff3 libdispatch.dylib`_dispatch_worker_thread2 + 109
    frame mono#30: 0x66024fa0 libsystem_pthread.dylib`_pthread_wqthread + 208
    frame mono#31: 0x66024e44 libsystem_pthread.dylib`start_wqthread + 36
```

Going further, `info` is about this thread:
```
(lldb) p/x *(int *)(((char *) info->node.key) + 0xa0)
(int) $2 = 0x01243f93
(lldb) thread list
Process 12832 stopped
  thread mono#1: tid = 0x1243ee1, 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10, name = 'tid_303', queue = 'com.apple.main-thread'
  thread mono#2: tid = 0x1243ee6, 0x65f816e2 libsystem_kernel.dylib`__recvfrom + 10
  thread mono#3: tid = 0x1243ee7, 0x65f81aea libsystem_kernel.dylib`__psynch_cvwait + 10, name = 'SGen worker'
  thread mono#4: tid = 0x1243ee9, 0x65f7e3d2 libsystem_kernel.dylib`semaphore_wait_trap + 10, name = 'Finalizer'
  thread mono#5: tid = 0x1243eea, 0x65f816e2 libsystem_kernel.dylib`__recvfrom + 10, name = 'Debugger agent'
  thread mono#6: tid = 0x1243f1d, 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10, name = 'com.apple.uikit.eventfetch-thread'
  thread mono#8: tid = 0x1243f93, 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10, name = 'tid_6d0f', queue = 'NSOperationQueue 0x8069b300 (QOS: UTILITY)'
* thread mono#9: tid = 0x12443a9, 0x00222870 WatchWCSessionAppWatchOSExtension`debugger_interrupt_critical(info=0x81365400, user_data=0xb04dc718) at debugger-agent.c:2716:6, name = 'tid_a31f', queue = 'NSOperationQueue 0x8069b670 (QOS: UTILITY)', stop reason = breakpoint 1.1
  thread mono#10: tid = 0x1244581, 0x65f7fd32 libsystem_kernel.dylib`__workq_kernreturn + 10
(lldb) thread select 8
* thread mono#8, name = 'tid_6d0f', queue = 'NSOperationQueue 0x8069b300 (QOS: UTILITY)'
    frame #0: 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10
libsystem_kernel.dylib`mach_msg_trap:
->  0x65f7e396 <+10>: retl
    0x65f7e397 <+11>: nop

libsystem_kernel.dylib`mach_msg_overwrite_trap:
    0x65f7e398 <+0>:  movl   $0xffffffe0, %eax         ; imm = 0xFFFFFFE0
    0x65f7e39d <+5>:  calll  0x65f85f44                ; _sysenter_trap
(lldb) bt
* thread mono#8, name = 'tid_6d0f', queue = 'NSOperationQueue 0x8069b300 (QOS: UTILITY)'
  * frame #0: 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10
    frame mono#1: 0x65f7e8ff libsystem_kernel.dylib`mach_msg + 47
    frame mono#2: 0x66079679 libxpc.dylib`_xpc_send_serializer + 104
    frame mono#3: 0x660794da libxpc.dylib`_xpc_pipe_simpleroutine + 80
    frame mono#4: 0x66079852 libxpc.dylib`xpc_pipe_simpleroutine + 43
    frame mono#5: 0x66043a8f libsystem_trace.dylib`___os_activity_stream_reflect_block_invoke_2 + 30
    frame mono#6: 0x65de126f libdispatch.dylib`_dispatch_client_callout + 14
    frame mono#7: 0x65de3d71 libdispatch.dylib`_dispatch_block_invoke_direct + 257
    frame mono#8: 0x65de3c62 libdispatch.dylib`dispatch_block_perform + 112
    frame mono#9: 0x6604349a libsystem_trace.dylib`_os_activity_stream_reflect + 725
    frame mono#10: 0x6604ef19 libsystem_trace.dylib`_os_log_impl_stream + 468
    frame mono#11: 0x6604e44d libsystem_trace.dylib`_os_log_impl_flatten_and_send + 6410
    frame mono#12: 0x6604cb3b libsystem_trace.dylib`_os_log + 137
    frame mono#13: 0x6604f4aa libsystem_trace.dylib`_os_log_impl + 31
    frame mono#14: 0x4b4eb4e9 WatchConnectivity`WCSerializePayloadDictionary + 393
    frame mono#15: 0x4b4d7c4d WatchConnectivity`-[WCSession onqueue_sendResponseDictionary:identifier:] + 195
    frame mono#16: 0x4b4da435 WatchConnectivity`__66-[WCSession onqueue_handleDictionaryMessageRequest:withPairingID:]_block_invoke.411 + 35
    frame mono#17: 0x453c7df7 Foundation`__NSBLOCKOPERATION_IS_CALLING_OUT_TO_A_BLOCK__ + 12
    frame mono#18: 0x453c7cf4 Foundation`-[NSBlockOperation main] + 88
    frame mono#19: 0x453cacee Foundation`__NSOPERATION_IS_INVOKING_MAIN__ + 27
    frame mono#20: 0x453c6ebd Foundation`-[NSOperation start] + 835
    frame mono#21: 0x453cb606 Foundation`__NSOPERATIONQUEUE_IS_STARTING_AN_OPERATION__ + 27
    frame mono#22: 0x453cb12e Foundation`__NSOQSchedule_f + 194
    frame mono#23: 0x453cb067 Foundation`____addOperations_block_invoke_2 + 20
    frame mono#24: 0x65dedf49 libdispatch.dylib`_dispatch_block_async_invoke2 + 77
    frame mono#25: 0x65de4461 libdispatch.dylib`_dispatch_block_async_invoke_and_release + 17
    frame mono#26: 0x65de126f libdispatch.dylib`_dispatch_client_callout + 14
    frame mono#27: 0x65de3788 libdispatch.dylib`_dispatch_continuation_pop + 421
    frame mono#28: 0x65de2ee3 libdispatch.dylib`_dispatch_async_redirect_invoke + 818
    frame mono#29: 0x65df087d libdispatch.dylib`_dispatch_root_queue_drain + 354
    frame mono#30: 0x65df0ff3 libdispatch.dylib`_dispatch_worker_thread2 + 109
    frame mono#31: 0x66024fa0 libsystem_pthread.dylib`_pthread_wqthread + 208
    frame mono#32: 0x66024e44 libsystem_pthread.dylib`start_wqthread + 36
```
which is a thread in a "light" detach state (aka. coop detach), where we only unset the domain:
https://github.com/mono/mono/blob/4cefdcb7ce2d939ee78fb45d1b4913eb3bc064fd/mono/metadata/threads.c#L6084-L6111

Fixes mono#17926
monojenkins added a commit that referenced this pull request Dec 10, 2019
@monojenkins
[debugger] skip suspend for unattached threads (#18110)
b951ebb 
[2019-12] [debugger] skip suspend for unattached threads

When the debugger tries to suspend all the VM threads, it can happen with cooperative-suspend that it tries to suspend a thread that has previously been attached, but then did a "light" detach (that only unsets the domain). With the domain set to `NULL`, looking up a JitInfo for a given `ip` will result into a crash, but it isn't even necessarily needed for the purpose of suspending a thread.

More details: Consider the following:
```
(lldb) c
error: Process is running.  Use 'process interrupt' to pause execution.
Process 12832 stopped
* thread #9, name = 'tid_a31f', queue = 'NSOperationQueue 0x8069b670 (QOS: UTILITY)', stop reason = breakpoint 1.1
    frame #0: 0x00222870 WatchWCSessionAppWatchOSExtension`debugger_interrupt_critical(info=0x81365400, user_data=0xb04dc718) at debugger-agent.c:2716:6
   2713         MonoDomain *domain = (MonoDomain *) mono_thread_info_get_suspend_state (info)->unwind_data [MONO_UNWIND_DATA_DOMAIN];
   2714         if (!domain) {
   2715                 /* not attached */
-> 2716                 ji = NULL;
   2717         } else {
   2718                 ji = mono_jit_info_table_find_internal ( domain, MONO_CONTEXT_GET_IP (&mono_thread_info_get_suspend_state (info)->ctx), TRUE, TRUE);
   2719         }
Target 0: (WatchWCSessionAppWatchOSExtension) stopped.
(lldb) bt
* thread #9, name = 'tid_a31f', queue = 'NSOperationQueue 0x8069b670 (QOS: UTILITY)', stop reason = breakpoint 1.1
  * frame #0: 0x00222870 WatchWCSessionAppWatchOSExtension`debugger_interrupt_critical(info=0x81365400, user_data=0xb04dc718) at debugger-agent.c:2716:6
    frame #1: 0x004e177b WatchWCSessionAppWatchOSExtension`mono_thread_info_safe_suspend_and_run(id=0xb0767000, interrupt_kernel=0, callback=(WatchWCSessionAppWatchOSExtension`debugger_interrupt_critical at debugger-agent.c:2708), user_data=0xb04dc718) at mono-threads.c:1358:19
    frame #2: 0x00222799 WatchWCSessionAppWatchOSExtension`notify_thread(key=0x03994508, value=0x81378c00, user_data=0x00000000) at debugger-agent.c:2747:2
    frame #3: 0x00355bd8 WatchWCSessionAppWatchOSExtension`mono_g_hash_table_foreach(hash=0x8007b4e0, func=(WatchWCSessionAppWatchOSExtension`notify_thread at debugger-agent.c:2733), user_data=0x00000000) at mono-hash.c:310:4
    frame #4: 0x0021e955 WatchWCSessionAppWatchOSExtension`suspend_vm at debugger-agent.c:2844:3
    frame #5: 0x00225ff0 WatchWCSessionAppWatchOSExtension`process_event(event=EVENT_KIND_THREAD_START, arg=0x039945d0, il_offset=0, ctx=0x00000000, events=0x805b28e0, suspend_policy=2) at debugger-agent.c:4012:3
    frame #6: 0x00227c7c WatchWCSessionAppWatchOSExtension`process_profiler_event(event=EVENT_KIND_THREAD_START, arg=0x039945d0) at debugger-agent.c:4072:2
    frame #7: 0x0021b174 WatchWCSessionAppWatchOSExtension`thread_startup(prof=0x00000000, tid=2957889536) at debugger-agent.c:4149:2
    frame #8: 0x0037912d WatchWCSessionAppWatchOSExtension`mono_profiler_raise_thread_started(tid=2957889536) at profiler-events.h:103:1
    frame #9: 0x003d53da WatchWCSessionAppWatchOSExtension`fire_attach_profiler_events(tid=0xb04dd000) at threads.c:1120:2
    frame #10: 0x003d4d83 WatchWCSessionAppWatchOSExtension`mono_thread_attach(domain=0x801750a0) at threads.c:1547:2
    frame #11: 0x003df1a1 WatchWCSessionAppWatchOSExtension`mono_threads_attach_coop_internal(domain=0x801750a0, cookie=0xb04dcc0c, stackdata=0xb04dcba8) at threads.c:6008:3
    frame #12: 0x003df287 WatchWCSessionAppWatchOSExtension`mono_threads_attach_coop(domain=0x00000000, dummy=0xb04dcc0c) at threads.c:6045:9
    frame #13: 0x005034b8 WatchWCSessionAppWatchOSExtension`::xamarin_switch_gchandle(self=0x80762c20, to_weak=false) at runtime.m:1805:2
    frame #14: 0x005065c1 WatchWCSessionAppWatchOSExtension`::xamarin_retain_trampoline(self=0x80762c20, sel="retain") at trampolines.m:693:2
    frame #15: 0x657ea520 libobjc.A.dylib`objc_retain + 64
    frame #16: 0x4b4d9caa WatchConnectivity`__66-[WCSession onqueue_handleDictionaryMessageRequest:withPairingID:]_block_invoke + 279
    frame #17: 0x453c7df7 Foundation`__NSBLOCKOPERATION_IS_CALLING_OUT_TO_A_BLOCK__ + 12
    frame #18: 0x453c7cf4 Foundation`-[NSBlockOperation main] + 88
    frame #19: 0x453cacee Foundation`__NSOPERATION_IS_INVOKING_MAIN__ + 27
    frame #20: 0x453c6ebd Foundation`-[NSOperation start] + 835
    frame #21: 0x453cb606 Foundation`__NSOPERATIONQUEUE_IS_STARTING_AN_OPERATION__ + 27
    frame #22: 0x453cb12e Foundation`__NSOQSchedule_f + 194
    frame #23: 0x453cb26e Foundation`____addOperations_block_invoke_4 + 20
    frame #24: 0x65de007b libdispatch.dylib`_dispatch_call_block_and_release + 15
    frame #25: 0x65de126f libdispatch.dylib`_dispatch_client_callout + 14
    frame #26: 0x65de3788 libdispatch.dylib`_dispatch_continuation_pop + 421
    frame #27: 0x65de2ee3 libdispatch.dylib`_dispatch_async_redirect_invoke + 818
    frame #28: 0x65df087d libdispatch.dylib`_dispatch_root_queue_drain + 354
    frame #29: 0x65df0ff3 libdispatch.dylib`_dispatch_worker_thread2 + 109
    frame #30: 0x66024fa0 libsystem_pthread.dylib`_pthread_wqthread + 208
    frame #31: 0x66024e44 libsystem_pthread.dylib`start_wqthread + 36
```

Going further, `info` is about this thread:
```
(lldb) p/x *(int *)(((char *) info->node.key) + 0xa0)
(int) $2 = 0x01243f93
(lldb) thread list
Process 12832 stopped
  thread #1: tid = 0x1243ee1, 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10, name = 'tid_303', queue = 'com.apple.main-thread'
  thread #2: tid = 0x1243ee6, 0x65f816e2 libsystem_kernel.dylib`__recvfrom + 10
  thread #3: tid = 0x1243ee7, 0x65f81aea libsystem_kernel.dylib`__psynch_cvwait + 10, name = 'SGen worker'
  thread #4: tid = 0x1243ee9, 0x65f7e3d2 libsystem_kernel.dylib`semaphore_wait_trap + 10, name = 'Finalizer'
  thread #5: tid = 0x1243eea, 0x65f816e2 libsystem_kernel.dylib`__recvfrom + 10, name = 'Debugger agent'
  thread #6: tid = 0x1243f1d, 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10, name = 'com.apple.uikit.eventfetch-thread'
  thread #8: tid = 0x1243f93, 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10, name = 'tid_6d0f', queue = 'NSOperationQueue 0x8069b300 (QOS: UTILITY)'
* thread #9: tid = 0x12443a9, 0x00222870 WatchWCSessionAppWatchOSExtension`debugger_interrupt_critical(info=0x81365400, user_data=0xb04dc718) at debugger-agent.c:2716:6, name = 'tid_a31f', queue = 'NSOperationQueue 0x8069b670 (QOS: UTILITY)', stop reason = breakpoint 1.1
  thread #10: tid = 0x1244581, 0x65f7fd32 libsystem_kernel.dylib`__workq_kernreturn + 10
(lldb) thread select 8
* thread #8, name = 'tid_6d0f', queue = 'NSOperationQueue 0x8069b300 (QOS: UTILITY)'
    frame #0: 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10
libsystem_kernel.dylib`mach_msg_trap:
->  0x65f7e396 <+10>: retl
    0x65f7e397 <+11>: nop

libsystem_kernel.dylib`mach_msg_overwrite_trap:
    0x65f7e398 <+0>:  movl   $0xffffffe0, %eax         ; imm = 0xFFFFFFE0
    0x65f7e39d <+5>:  calll  0x65f85f44                ; _sysenter_trap
(lldb) bt
* thread #8, name = 'tid_6d0f', queue = 'NSOperationQueue 0x8069b300 (QOS: UTILITY)'
  * frame #0: 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10
    frame #1: 0x65f7e8ff libsystem_kernel.dylib`mach_msg + 47
    frame #2: 0x66079679 libxpc.dylib`_xpc_send_serializer + 104
    frame #3: 0x660794da libxpc.dylib`_xpc_pipe_simpleroutine + 80
    frame #4: 0x66079852 libxpc.dylib`xpc_pipe_simpleroutine + 43
    frame #5: 0x66043a8f libsystem_trace.dylib`___os_activity_stream_reflect_block_invoke_2 + 30
    frame #6: 0x65de126f libdispatch.dylib`_dispatch_client_callout + 14
    frame #7: 0x65de3d71 libdispatch.dylib`_dispatch_block_invoke_direct + 257
    frame #8: 0x65de3c62 libdispatch.dylib`dispatch_block_perform + 112
    frame #9: 0x6604349a libsystem_trace.dylib`_os_activity_stream_reflect + 725
    frame #10: 0x6604ef19 libsystem_trace.dylib`_os_log_impl_stream + 468
    frame #11: 0x6604e44d libsystem_trace.dylib`_os_log_impl_flatten_and_send + 6410
    frame #12: 0x6604cb3b libsystem_trace.dylib`_os_log + 137
    frame #13: 0x6604f4aa libsystem_trace.dylib`_os_log_impl + 31
    frame #14: 0x4b4eb4e9 WatchConnectivity`WCSerializePayloadDictionary + 393
    frame #15: 0x4b4d7c4d WatchConnectivity`-[WCSession onqueue_sendResponseDictionary:identifier:] + 195
    frame #16: 0x4b4da435 WatchConnectivity`__66-[WCSession onqueue_handleDictionaryMessageRequest:withPairingID:]_block_invoke.411 + 35
    frame #17: 0x453c7df7 Foundation`__NSBLOCKOPERATION_IS_CALLING_OUT_TO_A_BLOCK__ + 12
    frame #18: 0x453c7cf4 Foundation`-[NSBlockOperation main] + 88
    frame #19: 0x453cacee Foundation`__NSOPERATION_IS_INVOKING_MAIN__ + 27
    frame #20: 0x453c6ebd Foundation`-[NSOperation start] + 835
    frame #21: 0x453cb606 Foundation`__NSOPERATIONQUEUE_IS_STARTING_AN_OPERATION__ + 27
    frame #22: 0x453cb12e Foundation`__NSOQSchedule_f + 194
    frame #23: 0x453cb067 Foundation`____addOperations_block_invoke_2 + 20
    frame #24: 0x65dedf49 libdispatch.dylib`_dispatch_block_async_invoke2 + 77
    frame #25: 0x65de4461 libdispatch.dylib`_dispatch_block_async_invoke_and_release + 17
    frame #26: 0x65de126f libdispatch.dylib`_dispatch_client_callout + 14
    frame #27: 0x65de3788 libdispatch.dylib`_dispatch_continuation_pop + 421
    frame #28: 0x65de2ee3 libdispatch.dylib`_dispatch_async_redirect_invoke + 818
    frame #29: 0x65df087d libdispatch.dylib`_dispatch_root_queue_drain + 354
    frame #30: 0x65df0ff3 libdispatch.dylib`_dispatch_worker_thread2 + 109
    frame #31: 0x66024fa0 libsystem_pthread.dylib`_pthread_wqthread + 208
    frame #32: 0x66024e44 libsystem_pthread.dylib`start_wqthread + 36
```
which is a thread in a "light" detach state (aka. coop detach), where we only unset the domain:
https://github.com/mono/mono/blob/4cefdcb7ce2d939ee78fb45d1b4913eb3bc064fd/mono/metadata/threads.c#L6084-L6111

Fixes #17926



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Backport of #18105.

/cc @lewurm
lambdageek pushed a commit that referenced this pull request Dec 10, 2019
@monojenkins @lambdageek
[debugger] skip suspend for unattached threads (#18111)
7c95e4b 
When the debugger tries to suspend all the VM threads, it can happen with cooperative-suspend that it tries to suspend a thread that has previously been attached, but then did a "light" detach (that only unsets the domain). With the domain set to `NULL`, looking up a JitInfo for a given `ip` will result into a crash, but it isn't even necessarily needed for the purpose of suspending a thread.

More details: Consider the following:
```
(lldb) c
error: Process is running.  Use 'process interrupt' to pause execution.
Process 12832 stopped
* thread #9, name = 'tid_a31f', queue = 'NSOperationQueue 0x8069b670 (QOS: UTILITY)', stop reason = breakpoint 1.1
    frame #0: 0x00222870 WatchWCSessionAppWatchOSExtension`debugger_interrupt_critical(info=0x81365400, user_data=0xb04dc718) at debugger-agent.c:2716:6
   2713         MonoDomain *domain = (MonoDomain *) mono_thread_info_get_suspend_state (info)->unwind_data [MONO_UNWIND_DATA_DOMAIN];
   2714         if (!domain) {
   2715                 /* not attached */
-> 2716                 ji = NULL;
   2717         } else {
   2718                 ji = mono_jit_info_table_find_internal ( domain, MONO_CONTEXT_GET_IP (&mono_thread_info_get_suspend_state (info)->ctx), TRUE, TRUE);
   2719         }
Target 0: (WatchWCSessionAppWatchOSExtension) stopped.
(lldb) bt
* thread #9, name = 'tid_a31f', queue = 'NSOperationQueue 0x8069b670 (QOS: UTILITY)', stop reason = breakpoint 1.1
  * frame #0: 0x00222870 WatchWCSessionAppWatchOSExtension`debugger_interrupt_critical(info=0x81365400, user_data=0xb04dc718) at debugger-agent.c:2716:6
    frame #1: 0x004e177b WatchWCSessionAppWatchOSExtension`mono_thread_info_safe_suspend_and_run(id=0xb0767000, interrupt_kernel=0, callback=(WatchWCSessionAppWatchOSExtension`debugger_interrupt_critical at debugger-agent.c:2708), user_data=0xb04dc718) at mono-threads.c:1358:19
    frame #2: 0x00222799 WatchWCSessionAppWatchOSExtension`notify_thread(key=0x03994508, value=0x81378c00, user_data=0x00000000) at debugger-agent.c:2747:2
    frame #3: 0x00355bd8 WatchWCSessionAppWatchOSExtension`mono_g_hash_table_foreach(hash=0x8007b4e0, func=(WatchWCSessionAppWatchOSExtension`notify_thread at debugger-agent.c:2733), user_data=0x00000000) at mono-hash.c:310:4
    frame #4: 0x0021e955 WatchWCSessionAppWatchOSExtension`suspend_vm at debugger-agent.c:2844:3
    frame #5: 0x00225ff0 WatchWCSessionAppWatchOSExtension`process_event(event=EVENT_KIND_THREAD_START, arg=0x039945d0, il_offset=0, ctx=0x00000000, events=0x805b28e0, suspend_policy=2) at debugger-agent.c:4012:3
    frame #6: 0x00227c7c WatchWCSessionAppWatchOSExtension`process_profiler_event(event=EVENT_KIND_THREAD_START, arg=0x039945d0) at debugger-agent.c:4072:2
    frame #7: 0x0021b174 WatchWCSessionAppWatchOSExtension`thread_startup(prof=0x00000000, tid=2957889536) at debugger-agent.c:4149:2
    frame #8: 0x0037912d WatchWCSessionAppWatchOSExtension`mono_profiler_raise_thread_started(tid=2957889536) at profiler-events.h:103:1
    frame #9: 0x003d53da WatchWCSessionAppWatchOSExtension`fire_attach_profiler_events(tid=0xb04dd000) at threads.c:1120:2
    frame #10: 0x003d4d83 WatchWCSessionAppWatchOSExtension`mono_thread_attach(domain=0x801750a0) at threads.c:1547:2
    frame #11: 0x003df1a1 WatchWCSessionAppWatchOSExtension`mono_threads_attach_coop_internal(domain=0x801750a0, cookie=0xb04dcc0c, stackdata=0xb04dcba8) at threads.c:6008:3
    frame #12: 0x003df287 WatchWCSessionAppWatchOSExtension`mono_threads_attach_coop(domain=0x00000000, dummy=0xb04dcc0c) at threads.c:6045:9
    frame #13: 0x005034b8 WatchWCSessionAppWatchOSExtension`::xamarin_switch_gchandle(self=0x80762c20, to_weak=false) at runtime.m:1805:2
    frame #14: 0x005065c1 WatchWCSessionAppWatchOSExtension`::xamarin_retain_trampoline(self=0x80762c20, sel="retain") at trampolines.m:693:2
    frame #15: 0x657ea520 libobjc.A.dylib`objc_retain + 64
    frame #16: 0x4b4d9caa WatchConnectivity`__66-[WCSession onqueue_handleDictionaryMessageRequest:withPairingID:]_block_invoke + 279
    frame #17: 0x453c7df7 Foundation`__NSBLOCKOPERATION_IS_CALLING_OUT_TO_A_BLOCK__ + 12
    frame #18: 0x453c7cf4 Foundation`-[NSBlockOperation main] + 88
    frame #19: 0x453cacee Foundation`__NSOPERATION_IS_INVOKING_MAIN__ + 27
    frame #20: 0x453c6ebd Foundation`-[NSOperation start] + 835
    frame #21: 0x453cb606 Foundation`__NSOPERATIONQUEUE_IS_STARTING_AN_OPERATION__ + 27
    frame #22: 0x453cb12e Foundation`__NSOQSchedule_f + 194
    frame #23: 0x453cb26e Foundation`____addOperations_block_invoke_4 + 20
    frame #24: 0x65de007b libdispatch.dylib`_dispatch_call_block_and_release + 15
    frame #25: 0x65de126f libdispatch.dylib`_dispatch_client_callout + 14
    frame #26: 0x65de3788 libdispatch.dylib`_dispatch_continuation_pop + 421
    frame #27: 0x65de2ee3 libdispatch.dylib`_dispatch_async_redirect_invoke + 818
    frame #28: 0x65df087d libdispatch.dylib`_dispatch_root_queue_drain + 354
    frame #29: 0x65df0ff3 libdispatch.dylib`_dispatch_worker_thread2 + 109
    frame #30: 0x66024fa0 libsystem_pthread.dylib`_pthread_wqthread + 208
    frame #31: 0x66024e44 libsystem_pthread.dylib`start_wqthread + 36
```

Going further, `info` is about this thread:
```
(lldb) p/x *(int *)(((char *) info->node.key) + 0xa0)
(int) $2 = 0x01243f93
(lldb) thread list
Process 12832 stopped
  thread #1: tid = 0x1243ee1, 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10, name = 'tid_303', queue = 'com.apple.main-thread'
  thread #2: tid = 0x1243ee6, 0x65f816e2 libsystem_kernel.dylib`__recvfrom + 10
  thread #3: tid = 0x1243ee7, 0x65f81aea libsystem_kernel.dylib`__psynch_cvwait + 10, name = 'SGen worker'
  thread #4: tid = 0x1243ee9, 0x65f7e3d2 libsystem_kernel.dylib`semaphore_wait_trap + 10, name = 'Finalizer'
  thread #5: tid = 0x1243eea, 0x65f816e2 libsystem_kernel.dylib`__recvfrom + 10, name = 'Debugger agent'
  thread #6: tid = 0x1243f1d, 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10, name = 'com.apple.uikit.eventfetch-thread'
  thread #8: tid = 0x1243f93, 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10, name = 'tid_6d0f', queue = 'NSOperationQueue 0x8069b300 (QOS: UTILITY)'
* thread #9: tid = 0x12443a9, 0x00222870 WatchWCSessionAppWatchOSExtension`debugger_interrupt_critical(info=0x81365400, user_data=0xb04dc718) at debugger-agent.c:2716:6, name = 'tid_a31f', queue = 'NSOperationQueue 0x8069b670 (QOS: UTILITY)', stop reason = breakpoint 1.1
  thread #10: tid = 0x1244581, 0x65f7fd32 libsystem_kernel.dylib`__workq_kernreturn + 10
(lldb) thread select 8
* thread #8, name = 'tid_6d0f', queue = 'NSOperationQueue 0x8069b300 (QOS: UTILITY)'
    frame #0: 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10
libsystem_kernel.dylib`mach_msg_trap:
->  0x65f7e396 <+10>: retl
    0x65f7e397 <+11>: nop

libsystem_kernel.dylib`mach_msg_overwrite_trap:
    0x65f7e398 <+0>:  movl   $0xffffffe0, %eax         ; imm = 0xFFFFFFE0
    0x65f7e39d <+5>:  calll  0x65f85f44                ; _sysenter_trap
(lldb) bt
* thread #8, name = 'tid_6d0f', queue = 'NSOperationQueue 0x8069b300 (QOS: UTILITY)'
  * frame #0: 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10
    frame #1: 0x65f7e8ff libsystem_kernel.dylib`mach_msg + 47
    frame #2: 0x66079679 libxpc.dylib`_xpc_send_serializer + 104
    frame #3: 0x660794da libxpc.dylib`_xpc_pipe_simpleroutine + 80
    frame #4: 0x66079852 libxpc.dylib`xpc_pipe_simpleroutine + 43
    frame #5: 0x66043a8f libsystem_trace.dylib`___os_activity_stream_reflect_block_invoke_2 + 30
    frame #6: 0x65de126f libdispatch.dylib`_dispatch_client_callout + 14
    frame #7: 0x65de3d71 libdispatch.dylib`_dispatch_block_invoke_direct + 257
    frame #8: 0x65de3c62 libdispatch.dylib`dispatch_block_perform + 112
    frame #9: 0x6604349a libsystem_trace.dylib`_os_activity_stream_reflect + 725
    frame #10: 0x6604ef19 libsystem_trace.dylib`_os_log_impl_stream + 468
    frame #11: 0x6604e44d libsystem_trace.dylib`_os_log_impl_flatten_and_send + 6410
    frame #12: 0x6604cb3b libsystem_trace.dylib`_os_log + 137
    frame #13: 0x6604f4aa libsystem_trace.dylib`_os_log_impl + 31
    frame #14: 0x4b4eb4e9 WatchConnectivity`WCSerializePayloadDictionary + 393
    frame #15: 0x4b4d7c4d WatchConnectivity`-[WCSession onqueue_sendResponseDictionary:identifier:] + 195
    frame #16: 0x4b4da435 WatchConnectivity`__66-[WCSession onqueue_handleDictionaryMessageRequest:withPairingID:]_block_invoke.411 + 35
    frame #17: 0x453c7df7 Foundation`__NSBLOCKOPERATION_IS_CALLING_OUT_TO_A_BLOCK__ + 12
    frame #18: 0x453c7cf4 Foundation`-[NSBlockOperation main] + 88
    frame #19: 0x453cacee Foundation`__NSOPERATION_IS_INVOKING_MAIN__ + 27
    frame #20: 0x453c6ebd Foundation`-[NSOperation start] + 835
    frame #21: 0x453cb606 Foundation`__NSOPERATIONQUEUE_IS_STARTING_AN_OPERATION__ + 27
    frame #22: 0x453cb12e Foundation`__NSOQSchedule_f + 194
    frame #23: 0x453cb067 Foundation`____addOperations_block_invoke_2 + 20
    frame #24: 0x65dedf49 libdispatch.dylib`_dispatch_block_async_invoke2 + 77
    frame #25: 0x65de4461 libdispatch.dylib`_dispatch_block_async_invoke_and_release + 17
    frame #26: 0x65de126f libdispatch.dylib`_dispatch_client_callout + 14
    frame #27: 0x65de3788 libdispatch.dylib`_dispatch_continuation_pop + 421
    frame #28: 0x65de2ee3 libdispatch.dylib`_dispatch_async_redirect_invoke + 818
    frame #29: 0x65df087d libdispatch.dylib`_dispatch_root_queue_drain + 354
    frame #30: 0x65df0ff3 libdispatch.dylib`_dispatch_worker_thread2 + 109
    frame #31: 0x66024fa0 libsystem_pthread.dylib`_pthread_wqthread + 208
    frame #32: 0x66024e44 libsystem_pthread.dylib`start_wqthread + 36
```
which is a thread in a "light" detach state (aka. coop detach), where we only unset the domain:
https://github.com/mono/mono/blob/4cefdcb7ce2d939ee78fb45d1b4913eb3bc064fd/mono/metadata/threads.c#L6084-L6111

Fixes #17926
monojenkins pushed a commit to monojenkins/mono that referenced this pull request Dec 11, 2019
@lewurm @monojenkins
[debugger] skip suspend for unattached threads
cf6037b 
When the debugger tries to suspend all the VM threads, it can happen with cooperative-suspend that it tries to suspend a thread that has previously been attached, but then did a "light" detach (that only unsets the domain). With the domain set to `NULL`, looking up a JitInfo for a given `ip` will result into a crash, but it isn't even necessarily needed for the purpose of suspending a thread.

More details: Consider the following:
```
(lldb) c
error: Process is running.  Use 'process interrupt' to pause execution.
Process 12832 stopped
* thread mono#9, name = 'tid_a31f', queue = 'NSOperationQueue 0x8069b670 (QOS: UTILITY)', stop reason = breakpoint 1.1
    frame #0: 0x00222870 WatchWCSessionAppWatchOSExtension`debugger_interrupt_critical(info=0x81365400, user_data=0xb04dc718) at debugger-agent.c:2716:6
   2713         MonoDomain *domain = (MonoDomain *) mono_thread_info_get_suspend_state (info)->unwind_data [MONO_UNWIND_DATA_DOMAIN];
   2714         if (!domain) {
   2715                 /* not attached */
-> 2716                 ji = NULL;
   2717         } else {
   2718                 ji = mono_jit_info_table_find_internal ( domain, MONO_CONTEXT_GET_IP (&mono_thread_info_get_suspend_state (info)->ctx), TRUE, TRUE);
   2719         }
Target 0: (WatchWCSessionAppWatchOSExtension) stopped.
(lldb) bt
* thread mono#9, name = 'tid_a31f', queue = 'NSOperationQueue 0x8069b670 (QOS: UTILITY)', stop reason = breakpoint 1.1
  * frame #0: 0x00222870 WatchWCSessionAppWatchOSExtension`debugger_interrupt_critical(info=0x81365400, user_data=0xb04dc718) at debugger-agent.c:2716:6
    frame mono#1: 0x004e177b WatchWCSessionAppWatchOSExtension`mono_thread_info_safe_suspend_and_run(id=0xb0767000, interrupt_kernel=0, callback=(WatchWCSessionAppWatchOSExtension`debugger_interrupt_critical at debugger-agent.c:2708), user_data=0xb04dc718) at mono-threads.c:1358:19
    frame mono#2: 0x00222799 WatchWCSessionAppWatchOSExtension`notify_thread(key=0x03994508, value=0x81378c00, user_data=0x00000000) at debugger-agent.c:2747:2
    frame mono#3: 0x00355bd8 WatchWCSessionAppWatchOSExtension`mono_g_hash_table_foreach(hash=0x8007b4e0, func=(WatchWCSessionAppWatchOSExtension`notify_thread at debugger-agent.c:2733), user_data=0x00000000) at mono-hash.c:310:4
    frame mono#4: 0x0021e955 WatchWCSessionAppWatchOSExtension`suspend_vm at debugger-agent.c:2844:3
    frame mono#5: 0x00225ff0 WatchWCSessionAppWatchOSExtension`process_event(event=EVENT_KIND_THREAD_START, arg=0x039945d0, il_offset=0, ctx=0x00000000, events=0x805b28e0, suspend_policy=2) at debugger-agent.c:4012:3
    frame mono#6: 0x00227c7c WatchWCSessionAppWatchOSExtension`process_profiler_event(event=EVENT_KIND_THREAD_START, arg=0x039945d0) at debugger-agent.c:4072:2
    frame mono#7: 0x0021b174 WatchWCSessionAppWatchOSExtension`thread_startup(prof=0x00000000, tid=2957889536) at debugger-agent.c:4149:2
    frame mono#8: 0x0037912d WatchWCSessionAppWatchOSExtension`mono_profiler_raise_thread_started(tid=2957889536) at profiler-events.h:103:1
    frame mono#9: 0x003d53da WatchWCSessionAppWatchOSExtension`fire_attach_profiler_events(tid=0xb04dd000) at threads.c:1120:2
    frame mono#10: 0x003d4d83 WatchWCSessionAppWatchOSExtension`mono_thread_attach(domain=0x801750a0) at threads.c:1547:2
    frame mono#11: 0x003df1a1 WatchWCSessionAppWatchOSExtension`mono_threads_attach_coop_internal(domain=0x801750a0, cookie=0xb04dcc0c, stackdata=0xb04dcba8) at threads.c:6008:3
    frame mono#12: 0x003df287 WatchWCSessionAppWatchOSExtension`mono_threads_attach_coop(domain=0x00000000, dummy=0xb04dcc0c) at threads.c:6045:9
    frame mono#13: 0x005034b8 WatchWCSessionAppWatchOSExtension`::xamarin_switch_gchandle(self=0x80762c20, to_weak=false) at runtime.m:1805:2
    frame mono#14: 0x005065c1 WatchWCSessionAppWatchOSExtension`::xamarin_retain_trampoline(self=0x80762c20, sel="retain") at trampolines.m:693:2
    frame mono#15: 0x657ea520 libobjc.A.dylib`objc_retain + 64
    frame mono#16: 0x4b4d9caa WatchConnectivity`__66-[WCSession onqueue_handleDictionaryMessageRequest:withPairingID:]_block_invoke + 279
    frame mono#17: 0x453c7df7 Foundation`__NSBLOCKOPERATION_IS_CALLING_OUT_TO_A_BLOCK__ + 12
    frame mono#18: 0x453c7cf4 Foundation`-[NSBlockOperation main] + 88
    frame mono#19: 0x453cacee Foundation`__NSOPERATION_IS_INVOKING_MAIN__ + 27
    frame mono#20: 0x453c6ebd Foundation`-[NSOperation start] + 835
    frame mono#21: 0x453cb606 Foundation`__NSOPERATIONQUEUE_IS_STARTING_AN_OPERATION__ + 27
    frame mono#22: 0x453cb12e Foundation`__NSOQSchedule_f + 194
    frame mono#23: 0x453cb26e Foundation`____addOperations_block_invoke_4 + 20
    frame mono#24: 0x65de007b libdispatch.dylib`_dispatch_call_block_and_release + 15
    frame mono#25: 0x65de126f libdispatch.dylib`_dispatch_client_callout + 14
    frame mono#26: 0x65de3788 libdispatch.dylib`_dispatch_continuation_pop + 421
    frame mono#27: 0x65de2ee3 libdispatch.dylib`_dispatch_async_redirect_invoke + 818
    frame mono#28: 0x65df087d libdispatch.dylib`_dispatch_root_queue_drain + 354
    frame mono#29: 0x65df0ff3 libdispatch.dylib`_dispatch_worker_thread2 + 109
    frame mono#30: 0x66024fa0 libsystem_pthread.dylib`_pthread_wqthread + 208
    frame mono#31: 0x66024e44 libsystem_pthread.dylib`start_wqthread + 36
```

Going further, `info` is about this thread:
```
(lldb) p/x *(int *)(((char *) info->node.key) + 0xa0)
(int) $2 = 0x01243f93
(lldb) thread list
Process 12832 stopped
  thread mono#1: tid = 0x1243ee1, 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10, name = 'tid_303', queue = 'com.apple.main-thread'
  thread mono#2: tid = 0x1243ee6, 0x65f816e2 libsystem_kernel.dylib`__recvfrom + 10
  thread mono#3: tid = 0x1243ee7, 0x65f81aea libsystem_kernel.dylib`__psynch_cvwait + 10, name = 'SGen worker'
  thread mono#4: tid = 0x1243ee9, 0x65f7e3d2 libsystem_kernel.dylib`semaphore_wait_trap + 10, name = 'Finalizer'
  thread mono#5: tid = 0x1243eea, 0x65f816e2 libsystem_kernel.dylib`__recvfrom + 10, name = 'Debugger agent'
  thread mono#6: tid = 0x1243f1d, 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10, name = 'com.apple.uikit.eventfetch-thread'
  thread mono#8: tid = 0x1243f93, 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10, name = 'tid_6d0f', queue = 'NSOperationQueue 0x8069b300 (QOS: UTILITY)'
* thread mono#9: tid = 0x12443a9, 0x00222870 WatchWCSessionAppWatchOSExtension`debugger_interrupt_critical(info=0x81365400, user_data=0xb04dc718) at debugger-agent.c:2716:6, name = 'tid_a31f', queue = 'NSOperationQueue 0x8069b670 (QOS: UTILITY)', stop reason = breakpoint 1.1
  thread mono#10: tid = 0x1244581, 0x65f7fd32 libsystem_kernel.dylib`__workq_kernreturn + 10
(lldb) thread select 8
* thread mono#8, name = 'tid_6d0f', queue = 'NSOperationQueue 0x8069b300 (QOS: UTILITY)'
    frame #0: 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10
libsystem_kernel.dylib`mach_msg_trap:
->  0x65f7e396 <+10>: retl
    0x65f7e397 <+11>: nop

libsystem_kernel.dylib`mach_msg_overwrite_trap:
    0x65f7e398 <+0>:  movl   $0xffffffe0, %eax         ; imm = 0xFFFFFFE0
    0x65f7e39d <+5>:  calll  0x65f85f44                ; _sysenter_trap
(lldb) bt
* thread mono#8, name = 'tid_6d0f', queue = 'NSOperationQueue 0x8069b300 (QOS: UTILITY)'
  * frame #0: 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10
    frame mono#1: 0x65f7e8ff libsystem_kernel.dylib`mach_msg + 47
    frame mono#2: 0x66079679 libxpc.dylib`_xpc_send_serializer + 104
    frame mono#3: 0x660794da libxpc.dylib`_xpc_pipe_simpleroutine + 80
    frame mono#4: 0x66079852 libxpc.dylib`xpc_pipe_simpleroutine + 43
    frame mono#5: 0x66043a8f libsystem_trace.dylib`___os_activity_stream_reflect_block_invoke_2 + 30
    frame mono#6: 0x65de126f libdispatch.dylib`_dispatch_client_callout + 14
    frame mono#7: 0x65de3d71 libdispatch.dylib`_dispatch_block_invoke_direct + 257
    frame mono#8: 0x65de3c62 libdispatch.dylib`dispatch_block_perform + 112
    frame mono#9: 0x6604349a libsystem_trace.dylib`_os_activity_stream_reflect + 725
    frame mono#10: 0x6604ef19 libsystem_trace.dylib`_os_log_impl_stream + 468
    frame mono#11: 0x6604e44d libsystem_trace.dylib`_os_log_impl_flatten_and_send + 6410
    frame mono#12: 0x6604cb3b libsystem_trace.dylib`_os_log + 137
    frame mono#13: 0x6604f4aa libsystem_trace.dylib`_os_log_impl + 31
    frame mono#14: 0x4b4eb4e9 WatchConnectivity`WCSerializePayloadDictionary + 393
    frame mono#15: 0x4b4d7c4d WatchConnectivity`-[WCSession onqueue_sendResponseDictionary:identifier:] + 195
    frame mono#16: 0x4b4da435 WatchConnectivity`__66-[WCSession onqueue_handleDictionaryMessageRequest:withPairingID:]_block_invoke.411 + 35
    frame mono#17: 0x453c7df7 Foundation`__NSBLOCKOPERATION_IS_CALLING_OUT_TO_A_BLOCK__ + 12
    frame mono#18: 0x453c7cf4 Foundation`-[NSBlockOperation main] + 88
    frame mono#19: 0x453cacee Foundation`__NSOPERATION_IS_INVOKING_MAIN__ + 27
    frame mono#20: 0x453c6ebd Foundation`-[NSOperation start] + 835
    frame mono#21: 0x453cb606 Foundation`__NSOPERATIONQUEUE_IS_STARTING_AN_OPERATION__ + 27
    frame mono#22: 0x453cb12e Foundation`__NSOQSchedule_f + 194
    frame mono#23: 0x453cb067 Foundation`____addOperations_block_invoke_2 + 20
    frame mono#24: 0x65dedf49 libdispatch.dylib`_dispatch_block_async_invoke2 + 77
    frame mono#25: 0x65de4461 libdispatch.dylib`_dispatch_block_async_invoke_and_release + 17
    frame mono#26: 0x65de126f libdispatch.dylib`_dispatch_client_callout + 14
    frame mono#27: 0x65de3788 libdispatch.dylib`_dispatch_continuation_pop + 421
    frame mono#28: 0x65de2ee3 libdispatch.dylib`_dispatch_async_redirect_invoke + 818
    frame mono#29: 0x65df087d libdispatch.dylib`_dispatch_root_queue_drain + 354
    frame mono#30: 0x65df0ff3 libdispatch.dylib`_dispatch_worker_thread2 + 109
    frame mono#31: 0x66024fa0 libsystem_pthread.dylib`_pthread_wqthread + 208
    frame mono#32: 0x66024e44 libsystem_pthread.dylib`start_wqthread + 36
```
which is a thread in a "light" detach state (aka. coop detach), where we only unset the domain:
https://github.com/mono/mono/blob/4cefdcb7ce2d939ee78fb45d1b4913eb3bc064fd/mono/metadata/threads.c#L6084-L6111

Fixes mono#17926
monojenkins added a commit that referenced this pull request Dec 12, 2019
@monojenkins
[debugger] skip suspend for unattached threads (#18138)
e3084ec 
[2019-08] [debugger] skip suspend for unattached threads

When the debugger tries to suspend all the VM threads, it can happen with cooperative-suspend that it tries to suspend a thread that has previously been attached, but then did a "light" detach (that only unsets the domain). With the domain set to `NULL`, looking up a JitInfo for a given `ip` will result into a crash, but it isn't even necessarily needed for the purpose of suspending a thread.

More details: Consider the following:
```
(lldb) c
error: Process is running.  Use 'process interrupt' to pause execution.
Process 12832 stopped
* thread #9, name = 'tid_a31f', queue = 'NSOperationQueue 0x8069b670 (QOS: UTILITY)', stop reason = breakpoint 1.1
    frame #0: 0x00222870 WatchWCSessionAppWatchOSExtension`debugger_interrupt_critical(info=0x81365400, user_data=0xb04dc718) at debugger-agent.c:2716:6
   2713         MonoDomain *domain = (MonoDomain *) mono_thread_info_get_suspend_state (info)->unwind_data [MONO_UNWIND_DATA_DOMAIN];
   2714         if (!domain) {
   2715                 /* not attached */
-> 2716                 ji = NULL;
   2717         } else {
   2718                 ji = mono_jit_info_table_find_internal ( domain, MONO_CONTEXT_GET_IP (&mono_thread_info_get_suspend_state (info)->ctx), TRUE, TRUE);
   2719         }
Target 0: (WatchWCSessionAppWatchOSExtension) stopped.
(lldb) bt
* thread #9, name = 'tid_a31f', queue = 'NSOperationQueue 0x8069b670 (QOS: UTILITY)', stop reason = breakpoint 1.1
  * frame #0: 0x00222870 WatchWCSessionAppWatchOSExtension`debugger_interrupt_critical(info=0x81365400, user_data=0xb04dc718) at debugger-agent.c:2716:6
    frame #1: 0x004e177b WatchWCSessionAppWatchOSExtension`mono_thread_info_safe_suspend_and_run(id=0xb0767000, interrupt_kernel=0, callback=(WatchWCSessionAppWatchOSExtension`debugger_interrupt_critical at debugger-agent.c:2708), user_data=0xb04dc718) at mono-threads.c:1358:19
    frame #2: 0x00222799 WatchWCSessionAppWatchOSExtension`notify_thread(key=0x03994508, value=0x81378c00, user_data=0x00000000) at debugger-agent.c:2747:2
    frame #3: 0x00355bd8 WatchWCSessionAppWatchOSExtension`mono_g_hash_table_foreach(hash=0x8007b4e0, func=(WatchWCSessionAppWatchOSExtension`notify_thread at debugger-agent.c:2733), user_data=0x00000000) at mono-hash.c:310:4
    frame #4: 0x0021e955 WatchWCSessionAppWatchOSExtension`suspend_vm at debugger-agent.c:2844:3
    frame #5: 0x00225ff0 WatchWCSessionAppWatchOSExtension`process_event(event=EVENT_KIND_THREAD_START, arg=0x039945d0, il_offset=0, ctx=0x00000000, events=0x805b28e0, suspend_policy=2) at debugger-agent.c:4012:3
    frame #6: 0x00227c7c WatchWCSessionAppWatchOSExtension`process_profiler_event(event=EVENT_KIND_THREAD_START, arg=0x039945d0) at debugger-agent.c:4072:2
    frame #7: 0x0021b174 WatchWCSessionAppWatchOSExtension`thread_startup(prof=0x00000000, tid=2957889536) at debugger-agent.c:4149:2
    frame #8: 0x0037912d WatchWCSessionAppWatchOSExtension`mono_profiler_raise_thread_started(tid=2957889536) at profiler-events.h:103:1
    frame #9: 0x003d53da WatchWCSessionAppWatchOSExtension`fire_attach_profiler_events(tid=0xb04dd000) at threads.c:1120:2
    frame #10: 0x003d4d83 WatchWCSessionAppWatchOSExtension`mono_thread_attach(domain=0x801750a0) at threads.c:1547:2
    frame #11: 0x003df1a1 WatchWCSessionAppWatchOSExtension`mono_threads_attach_coop_internal(domain=0x801750a0, cookie=0xb04dcc0c, stackdata=0xb04dcba8) at threads.c:6008:3
    frame #12: 0x003df287 WatchWCSessionAppWatchOSExtension`mono_threads_attach_coop(domain=0x00000000, dummy=0xb04dcc0c) at threads.c:6045:9
    frame #13: 0x005034b8 WatchWCSessionAppWatchOSExtension`::xamarin_switch_gchandle(self=0x80762c20, to_weak=false) at runtime.m:1805:2
    frame #14: 0x005065c1 WatchWCSessionAppWatchOSExtension`::xamarin_retain_trampoline(self=0x80762c20, sel="retain") at trampolines.m:693:2
    frame #15: 0x657ea520 libobjc.A.dylib`objc_retain + 64
    frame #16: 0x4b4d9caa WatchConnectivity`__66-[WCSession onqueue_handleDictionaryMessageRequest:withPairingID:]_block_invoke + 279
    frame #17: 0x453c7df7 Foundation`__NSBLOCKOPERATION_IS_CALLING_OUT_TO_A_BLOCK__ + 12
    frame #18: 0x453c7cf4 Foundation`-[NSBlockOperation main] + 88
    frame #19: 0x453cacee Foundation`__NSOPERATION_IS_INVOKING_MAIN__ + 27
    frame #20: 0x453c6ebd Foundation`-[NSOperation start] + 835
    frame #21: 0x453cb606 Foundation`__NSOPERATIONQUEUE_IS_STARTING_AN_OPERATION__ + 27
    frame #22: 0x453cb12e Foundation`__NSOQSchedule_f + 194
    frame #23: 0x453cb26e Foundation`____addOperations_block_invoke_4 + 20
    frame #24: 0x65de007b libdispatch.dylib`_dispatch_call_block_and_release + 15
    frame #25: 0x65de126f libdispatch.dylib`_dispatch_client_callout + 14
    frame #26: 0x65de3788 libdispatch.dylib`_dispatch_continuation_pop + 421
    frame #27: 0x65de2ee3 libdispatch.dylib`_dispatch_async_redirect_invoke + 818
    frame #28: 0x65df087d libdispatch.dylib`_dispatch_root_queue_drain + 354
    frame #29: 0x65df0ff3 libdispatch.dylib`_dispatch_worker_thread2 + 109
    frame #30: 0x66024fa0 libsystem_pthread.dylib`_pthread_wqthread + 208
    frame #31: 0x66024e44 libsystem_pthread.dylib`start_wqthread + 36
```

Going further, `info` is about this thread:
```
(lldb) p/x *(int *)(((char *) info->node.key) + 0xa0)
(int) $2 = 0x01243f93
(lldb) thread list
Process 12832 stopped
  thread #1: tid = 0x1243ee1, 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10, name = 'tid_303', queue = 'com.apple.main-thread'
  thread #2: tid = 0x1243ee6, 0x65f816e2 libsystem_kernel.dylib`__recvfrom + 10
  thread #3: tid = 0x1243ee7, 0x65f81aea libsystem_kernel.dylib`__psynch_cvwait + 10, name = 'SGen worker'
  thread #4: tid = 0x1243ee9, 0x65f7e3d2 libsystem_kernel.dylib`semaphore_wait_trap + 10, name = 'Finalizer'
  thread #5: tid = 0x1243eea, 0x65f816e2 libsystem_kernel.dylib`__recvfrom + 10, name = 'Debugger agent'
  thread #6: tid = 0x1243f1d, 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10, name = 'com.apple.uikit.eventfetch-thread'
  thread #8: tid = 0x1243f93, 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10, name = 'tid_6d0f', queue = 'NSOperationQueue 0x8069b300 (QOS: UTILITY)'
* thread #9: tid = 0x12443a9, 0x00222870 WatchWCSessionAppWatchOSExtension`debugger_interrupt_critical(info=0x81365400, user_data=0xb04dc718) at debugger-agent.c:2716:6, name = 'tid_a31f', queue = 'NSOperationQueue 0x8069b670 (QOS: UTILITY)', stop reason = breakpoint 1.1
  thread #10: tid = 0x1244581, 0x65f7fd32 libsystem_kernel.dylib`__workq_kernreturn + 10
(lldb) thread select 8
* thread #8, name = 'tid_6d0f', queue = 'NSOperationQueue 0x8069b300 (QOS: UTILITY)'
    frame #0: 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10
libsystem_kernel.dylib`mach_msg_trap:
->  0x65f7e396 <+10>: retl
    0x65f7e397 <+11>: nop

libsystem_kernel.dylib`mach_msg_overwrite_trap:
    0x65f7e398 <+0>:  movl   $0xffffffe0, %eax         ; imm = 0xFFFFFFE0
    0x65f7e39d <+5>:  calll  0x65f85f44                ; _sysenter_trap
(lldb) bt
* thread #8, name = 'tid_6d0f', queue = 'NSOperationQueue 0x8069b300 (QOS: UTILITY)'
  * frame #0: 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10
    frame #1: 0x65f7e8ff libsystem_kernel.dylib`mach_msg + 47
    frame #2: 0x66079679 libxpc.dylib`_xpc_send_serializer + 104
    frame #3: 0x660794da libxpc.dylib`_xpc_pipe_simpleroutine + 80
    frame #4: 0x66079852 libxpc.dylib`xpc_pipe_simpleroutine + 43
    frame #5: 0x66043a8f libsystem_trace.dylib`___os_activity_stream_reflect_block_invoke_2 + 30
    frame #6: 0x65de126f libdispatch.dylib`_dispatch_client_callout + 14
    frame #7: 0x65de3d71 libdispatch.dylib`_dispatch_block_invoke_direct + 257
    frame #8: 0x65de3c62 libdispatch.dylib`dispatch_block_perform + 112
    frame #9: 0x6604349a libsystem_trace.dylib`_os_activity_stream_reflect + 725
    frame #10: 0x6604ef19 libsystem_trace.dylib`_os_log_impl_stream + 468
    frame #11: 0x6604e44d libsystem_trace.dylib`_os_log_impl_flatten_and_send + 6410
    frame #12: 0x6604cb3b libsystem_trace.dylib`_os_log + 137
    frame #13: 0x6604f4aa libsystem_trace.dylib`_os_log_impl + 31
    frame #14: 0x4b4eb4e9 WatchConnectivity`WCSerializePayloadDictionary + 393
    frame #15: 0x4b4d7c4d WatchConnectivity`-[WCSession onqueue_sendResponseDictionary:identifier:] + 195
    frame #16: 0x4b4da435 WatchConnectivity`__66-[WCSession onqueue_handleDictionaryMessageRequest:withPairingID:]_block_invoke.411 + 35
    frame #17: 0x453c7df7 Foundation`__NSBLOCKOPERATION_IS_CALLING_OUT_TO_A_BLOCK__ + 12
    frame #18: 0x453c7cf4 Foundation`-[NSBlockOperation main] + 88
    frame #19: 0x453cacee Foundation`__NSOPERATION_IS_INVOKING_MAIN__ + 27
    frame #20: 0x453c6ebd Foundation`-[NSOperation start] + 835
    frame #21: 0x453cb606 Foundation`__NSOPERATIONQUEUE_IS_STARTING_AN_OPERATION__ + 27
    frame #22: 0x453cb12e Foundation`__NSOQSchedule_f + 194
    frame #23: 0x453cb067 Foundation`____addOperations_block_invoke_2 + 20
    frame #24: 0x65dedf49 libdispatch.dylib`_dispatch_block_async_invoke2 + 77
    frame #25: 0x65de4461 libdispatch.dylib`_dispatch_block_async_invoke_and_release + 17
    frame #26: 0x65de126f libdispatch.dylib`_dispatch_client_callout + 14
    frame #27: 0x65de3788 libdispatch.dylib`_dispatch_continuation_pop + 421
    frame #28: 0x65de2ee3 libdispatch.dylib`_dispatch_async_redirect_invoke + 818
    frame #29: 0x65df087d libdispatch.dylib`_dispatch_root_queue_drain + 354
    frame #30: 0x65df0ff3 libdispatch.dylib`_dispatch_worker_thread2 + 109
    frame #31: 0x66024fa0 libsystem_pthread.dylib`_pthread_wqthread + 208
    frame #32: 0x66024e44 libsystem_pthread.dylib`start_wqthread + 36
```
which is a thread in a "light" detach state (aka. coop detach), where we only unset the domain:
https://github.com/mono/mono/blob/4cefdcb7ce2d939ee78fb45d1b4913eb3bc064fd/mono/metadata/threads.c#L6084-L6111

Fixes #17926



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Backport of #18105.

/cc @lewurm
@fanyang-mono fanyang-mono mentioned this pull request Dec 17, 2019
Closed
ManickaP pushed a commit to ManickaP/runtime that referenced this pull request Jan 20, 2020
@lewurm
[threads] clear small_id_key TLS when unregistering a thread (mono/mo…
0fe830c 
…no#16973)

* [threads] clear small_id_key TLS when unregistering a thread

Fixes
```
* thread mono/mono#12, name = 'tid_a507', stop reason = EXC_BREAKPOINT (code=1, subcode=0x1be66144)
  * frame mono/mono#0: 0x1be66144 libsystem_c.dylib`__abort + 184
    frame mono/mono#1: 0x1be6608c libsystem_c.dylib`abort + 152
    frame mono/mono#2: 0x003e1fa0 monotouchtest`log_callback(log_domain=0x00000000, log_level="error", message="* Assertion at ../../../../../mono/utils/hazard-pointer.c:158, condition `mono_bitset_test_fast (small_id_table, id)' not met\n", fatal=4, user_data=0x00000000) at runtime.m:1251:3
    frame mono/mono#3: 0x003abf44 monotouchtest`monoeg_g_logv_nofree(log_domain=0x00000000, log_level=G_LOG_LEVEL_ERROR, format=<unavailable>, args=<unavailable>) at goutput.c:149:2 [opt]
    frame mono/mono#4: 0x003abfb4 monotouchtest`monoeg_assertion_message(format=<unavailable>) at goutput.c:184:22 [opt]
    frame mono/mono#5: 0x003904dc monotouchtest`mono_thread_small_id_free(id=<unavailable>) at hazard-pointer.c:0:2 [opt]
    frame mono/mono#6: 0x003a0a74 monotouchtest`unregister_thread(arg=0x15c88400) at mono-threads.c:588:2 [opt]
    frame mono/mono#7: 0x00336110 monotouchtest`mono_thread_detach_if_exiting at threads.c:1571:4 [opt]
    frame mono/mono#8: 0x003e7a14 monotouchtest`::xamarin_release_trampoline(self=0x166452f0, sel="release") at trampolines.m:644:3
    frame mono/mono#9: 0x001cdc40 monotouchtest`::-[__Xamarin_NSTimerActionDispatcher release](self=0x166452f0, _cmd="release") at registrar.m:83445:3
    frame mono/mono#10: 0x1ce2ae68 Foundation`_timerRelease + 80
    frame mono/mono#11: 0x1c31b56c CoreFoundation`CFRunLoopTimerInvalidate + 612
    frame mono/mono#12: 0x1c31a554 CoreFoundation`__CFRunLoopTimerDeallocate + 32
    frame mono/mono#13: 0x1c31dde4 CoreFoundation`_CFRelease + 220
    frame mono/mono#14: 0x1c2be6e8 CoreFoundation`__CFArrayReleaseValues + 500
    frame mono/mono#15: 0x1c2be4c4 CoreFoundation`CFArrayRemoveAllValues + 104
    frame mono/mono#16: 0x1c31ff64 CoreFoundation`__CFSetApplyFunction_block_invoke + 24
    frame mono/mono#17: 0x1c3b2e18 CoreFoundation`CFBasicHashApply + 116
    frame mono/mono#18: 0x1c31ff10 CoreFoundation`CFSetApplyFunction + 160
    frame mono/mono#19: 0x1c3152cc CoreFoundation`__CFRunLoopDeallocate + 204
    frame mono/mono#20: 0x1c31dde4 CoreFoundation`_CFRelease + 220
    frame mono/mono#21: 0x1c304a80 CoreFoundation`__CFTSDFinalize + 144
    frame mono/mono#22: 0x1bfa324c libsystem_pthread.dylib`_pthread_tsd_cleanup + 644
    frame mono/mono#23: 0x1bf9cc08 libsystem_pthread.dylib`_pthread_exit + 80
    frame mono/mono#24: 0x1bf9af24 libsystem_pthread.dylib`pthread_exit + 36
    frame mono/mono#25: 0x0039df84 monotouchtest`mono_threads_platform_exit(exit_code=<unavailable>) at mono-threads-posix.c:145:2 [opt]
    frame mono/mono#26: 0x0033bb84 monotouchtest`start_wrapper(data=0x1609e1c0) at threads.c:1296:2 [opt]
    frame mono/mono#27: 0x1bf9b914 libsystem_pthread.dylib`_pthread_body + 128
    frame mono/mono#28: 0x1bf9b874 libsystem_pthread.dylib`_pthread_start + 44
    frame mono/mono#29: 0x1bfa3b94 libsystem_pthread.dylib`thread_start + 4
```

* Update mono/utils/mono-threads.c

Co-Authored-By: Aleksey Kliger (λgeek) <akliger@gmail.com>


Commit migrated from mono/mono@749493d
ManickaP pushed a commit to ManickaP/runtime that referenced this pull request Jan 20, 2020
@lewurm
[debugger] skip suspend for unattached threads (mono/mono#18105)
35f16d6 
When the debugger tries to suspend all the VM threads, it can happen with cooperative-suspend that it tries to suspend a thread that has previously been attached, but then did a "light" detach (that only unsets the domain). With the domain set to `NULL`, looking up a JitInfo for a given `ip` will result into a crash, but it isn't even necessarily needed for the purpose of suspending a thread.

More details: Consider the following:
```
(lldb) c
error: Process is running.  Use 'process interrupt' to pause execution.
Process 12832 stopped
* thread mono/mono#9, name = 'tid_a31f', queue = 'NSOperationQueue 0x8069b670 (QOS: UTILITY)', stop reason = breakpoint 1.1
    frame mono/mono#0: 0x00222870 WatchWCSessionAppWatchOSExtension`debugger_interrupt_critical(info=0x81365400, user_data=0xb04dc718) at debugger-agent.c:2716:6
   2713         MonoDomain *domain = (MonoDomain *) mono_thread_info_get_suspend_state (info)->unwind_data [MONO_UNWIND_DATA_DOMAIN];
   2714         if (!domain) {
   2715                 /* not attached */
-> 2716                 ji = NULL;
   2717         } else {
   2718                 ji = mono_jit_info_table_find_internal ( domain, MONO_CONTEXT_GET_IP (&mono_thread_info_get_suspend_state (info)->ctx), TRUE, TRUE);
   2719         }
Target 0: (WatchWCSessionAppWatchOSExtension) stopped.
(lldb) bt
* thread mono/mono#9, name = 'tid_a31f', queue = 'NSOperationQueue 0x8069b670 (QOS: UTILITY)', stop reason = breakpoint 1.1
  * frame mono/mono#0: 0x00222870 WatchWCSessionAppWatchOSExtension`debugger_interrupt_critical(info=0x81365400, user_data=0xb04dc718) at debugger-agent.c:2716:6
    frame mono/mono#1: 0x004e177b WatchWCSessionAppWatchOSExtension`mono_thread_info_safe_suspend_and_run(id=0xb0767000, interrupt_kernel=0, callback=(WatchWCSessionAppWatchOSExtension`debugger_interrupt_critical at debugger-agent.c:2708), user_data=0xb04dc718) at mono-threads.c:1358:19
    frame mono/mono#2: 0x00222799 WatchWCSessionAppWatchOSExtension`notify_thread(key=0x03994508, value=0x81378c00, user_data=0x00000000) at debugger-agent.c:2747:2
    frame mono/mono#3: 0x00355bd8 WatchWCSessionAppWatchOSExtension`mono_g_hash_table_foreach(hash=0x8007b4e0, func=(WatchWCSessionAppWatchOSExtension`notify_thread at debugger-agent.c:2733), user_data=0x00000000) at mono-hash.c:310:4
    frame mono/mono#4: 0x0021e955 WatchWCSessionAppWatchOSExtension`suspend_vm at debugger-agent.c:2844:3
    frame mono/mono#5: 0x00225ff0 WatchWCSessionAppWatchOSExtension`process_event(event=EVENT_KIND_THREAD_START, arg=0x039945d0, il_offset=0, ctx=0x00000000, events=0x805b28e0, suspend_policy=2) at debugger-agent.c:4012:3
    frame mono/mono#6: 0x00227c7c WatchWCSessionAppWatchOSExtension`process_profiler_event(event=EVENT_KIND_THREAD_START, arg=0x039945d0) at debugger-agent.c:4072:2
    frame mono/mono#7: 0x0021b174 WatchWCSessionAppWatchOSExtension`thread_startup(prof=0x00000000, tid=2957889536) at debugger-agent.c:4149:2
    frame mono/mono#8: 0x0037912d WatchWCSessionAppWatchOSExtension`mono_profiler_raise_thread_started(tid=2957889536) at profiler-events.h:103:1
    frame mono/mono#9: 0x003d53da WatchWCSessionAppWatchOSExtension`fire_attach_profiler_events(tid=0xb04dd000) at threads.c:1120:2
    frame mono/mono#10: 0x003d4d83 WatchWCSessionAppWatchOSExtension`mono_thread_attach(domain=0x801750a0) at threads.c:1547:2
    frame mono/mono#11: 0x003df1a1 WatchWCSessionAppWatchOSExtension`mono_threads_attach_coop_internal(domain=0x801750a0, cookie=0xb04dcc0c, stackdata=0xb04dcba8) at threads.c:6008:3
    frame mono/mono#12: 0x003df287 WatchWCSessionAppWatchOSExtension`mono_threads_attach_coop(domain=0x00000000, dummy=0xb04dcc0c) at threads.c:6045:9
    frame mono/mono#13: 0x005034b8 WatchWCSessionAppWatchOSExtension`::xamarin_switch_gchandle(self=0x80762c20, to_weak=false) at runtime.m:1805:2
    frame mono/mono#14: 0x005065c1 WatchWCSessionAppWatchOSExtension`::xamarin_retain_trampoline(self=0x80762c20, sel="retain") at trampolines.m:693:2
    frame mono/mono#15: 0x657ea520 libobjc.A.dylib`objc_retain + 64
    frame mono/mono#16: 0x4b4d9caa WatchConnectivity`__66-[WCSession onqueue_handleDictionaryMessageRequest:withPairingID:]_block_invoke + 279
    frame mono/mono#17: 0x453c7df7 Foundation`__NSBLOCKOPERATION_IS_CALLING_OUT_TO_A_BLOCK__ + 12
    frame mono/mono#18: 0x453c7cf4 Foundation`-[NSBlockOperation main] + 88
    frame mono/mono#19: 0x453cacee Foundation`__NSOPERATION_IS_INVOKING_MAIN__ + 27
    frame mono/mono#20: 0x453c6ebd Foundation`-[NSOperation start] + 835
    frame mono/mono#21: 0x453cb606 Foundation`__NSOPERATIONQUEUE_IS_STARTING_AN_OPERATION__ + 27
    frame mono/mono#22: 0x453cb12e Foundation`__NSOQSchedule_f + 194
    frame mono/mono#23: 0x453cb26e Foundation`____addOperations_block_invoke_4 + 20
    frame mono/mono#24: 0x65de007b libdispatch.dylib`_dispatch_call_block_and_release + 15
    frame mono/mono#25: 0x65de126f libdispatch.dylib`_dispatch_client_callout + 14
    frame mono/mono#26: 0x65de3788 libdispatch.dylib`_dispatch_continuation_pop + 421
    frame mono/mono#27: 0x65de2ee3 libdispatch.dylib`_dispatch_async_redirect_invoke + 818
    frame mono/mono#28: 0x65df087d libdispatch.dylib`_dispatch_root_queue_drain + 354
    frame mono/mono#29: 0x65df0ff3 libdispatch.dylib`_dispatch_worker_thread2 + 109
    frame mono/mono#30: 0x66024fa0 libsystem_pthread.dylib`_pthread_wqthread + 208
    frame mono/mono#31: 0x66024e44 libsystem_pthread.dylib`start_wqthread + 36
```

Going further, `info` is about this thread:
```
(lldb) p/x *(int *)(((char *) info->node.key) + 0xa0)
(int) $2 = 0x01243f93
(lldb) thread list
Process 12832 stopped
  thread mono/mono#1: tid = 0x1243ee1, 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10, name = 'tid_303', queue = 'com.apple.main-thread'
  thread mono/mono#2: tid = 0x1243ee6, 0x65f816e2 libsystem_kernel.dylib`__recvfrom + 10
  thread mono/mono#3: tid = 0x1243ee7, 0x65f81aea libsystem_kernel.dylib`__psynch_cvwait + 10, name = 'SGen worker'
  thread mono/mono#4: tid = 0x1243ee9, 0x65f7e3d2 libsystem_kernel.dylib`semaphore_wait_trap + 10, name = 'Finalizer'
  thread mono/mono#5: tid = 0x1243eea, 0x65f816e2 libsystem_kernel.dylib`__recvfrom + 10, name = 'Debugger agent'
  thread mono/mono#6: tid = 0x1243f1d, 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10, name = 'com.apple.uikit.eventfetch-thread'
  thread mono/mono#8: tid = 0x1243f93, 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10, name = 'tid_6d0f', queue = 'NSOperationQueue 0x8069b300 (QOS: UTILITY)'
* thread mono/mono#9: tid = 0x12443a9, 0x00222870 WatchWCSessionAppWatchOSExtension`debugger_interrupt_critical(info=0x81365400, user_data=0xb04dc718) at debugger-agent.c:2716:6, name = 'tid_a31f', queue = 'NSOperationQueue 0x8069b670 (QOS: UTILITY)', stop reason = breakpoint 1.1
  thread mono/mono#10: tid = 0x1244581, 0x65f7fd32 libsystem_kernel.dylib`__workq_kernreturn + 10
(lldb) thread select 8
* thread mono/mono#8, name = 'tid_6d0f', queue = 'NSOperationQueue 0x8069b300 (QOS: UTILITY)'
    frame mono/mono#0: 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10
libsystem_kernel.dylib`mach_msg_trap:
->  0x65f7e396 <+10>: retl
    0x65f7e397 <+11>: nop

libsystem_kernel.dylib`mach_msg_overwrite_trap:
    0x65f7e398 <+0>:  movl   $0xffffffe0, %eax         ; imm = 0xFFFFFFE0
    0x65f7e39d <+5>:  calll  0x65f85f44                ; _sysenter_trap
(lldb) bt
* thread mono/mono#8, name = 'tid_6d0f', queue = 'NSOperationQueue 0x8069b300 (QOS: UTILITY)'
  * frame mono/mono#0: 0x65f7e396 libsystem_kernel.dylib`mach_msg_trap + 10
    frame mono/mono#1: 0x65f7e8ff libsystem_kernel.dylib`mach_msg + 47
    frame mono/mono#2: 0x66079679 libxpc.dylib`_xpc_send_serializer + 104
    frame mono/mono#3: 0x660794da libxpc.dylib`_xpc_pipe_simpleroutine + 80
    frame mono/mono#4: 0x66079852 libxpc.dylib`xpc_pipe_simpleroutine + 43
    frame mono/mono#5: 0x66043a8f libsystem_trace.dylib`___os_activity_stream_reflect_block_invoke_2 + 30
    frame mono/mono#6: 0x65de126f libdispatch.dylib`_dispatch_client_callout + 14
    frame mono/mono#7: 0x65de3d71 libdispatch.dylib`_dispatch_block_invoke_direct + 257
    frame mono/mono#8: 0x65de3c62 libdispatch.dylib`dispatch_block_perform + 112
    frame mono/mono#9: 0x6604349a libsystem_trace.dylib`_os_activity_stream_reflect + 725
    frame mono/mono#10: 0x6604ef19 libsystem_trace.dylib`_os_log_impl_stream + 468
    frame mono/mono#11: 0x6604e44d libsystem_trace.dylib`_os_log_impl_flatten_and_send + 6410
    frame mono/mono#12: 0x6604cb3b libsystem_trace.dylib`_os_log + 137
    frame mono/mono#13: 0x6604f4aa libsystem_trace.dylib`_os_log_impl + 31
    frame mono/mono#14: 0x4b4eb4e9 WatchConnectivity`WCSerializePayloadDictionary + 393
    frame mono/mono#15: 0x4b4d7c4d WatchConnectivity`-[WCSession onqueue_sendResponseDictionary:identifier:] + 195
    frame mono/mono#16: 0x4b4da435 WatchConnectivity`__66-[WCSession onqueue_handleDictionaryMessageRequest:withPairingID:]_block_invoke.411 + 35
    frame mono/mono#17: 0x453c7df7 Foundation`__NSBLOCKOPERATION_IS_CALLING_OUT_TO_A_BLOCK__ + 12
    frame mono/mono#18: 0x453c7cf4 Foundation`-[NSBlockOperation main] + 88
    frame mono/mono#19: 0x453cacee Foundation`__NSOPERATION_IS_INVOKING_MAIN__ + 27
    frame mono/mono#20: 0x453c6ebd Foundation`-[NSOperation start] + 835
    frame mono/mono#21: 0x453cb606 Foundation`__NSOPERATIONQUEUE_IS_STARTING_AN_OPERATION__ + 27
    frame mono/mono#22: 0x453cb12e Foundation`__NSOQSchedule_f + 194
    frame mono/mono#23: 0x453cb067 Foundation`____addOperations_block_invoke_2 + 20
    frame mono/mono#24: 0x65dedf49 libdispatch.dylib`_dispatch_block_async_invoke2 + 77
    frame mono/mono#25: 0x65de4461 libdispatch.dylib`_dispatch_block_async_invoke_and_release + 17
    frame mono/mono#26: 0x65de126f libdispatch.dylib`_dispatch_client_callout + 14
    frame mono/mono#27: 0x65de3788 libdispatch.dylib`_dispatch_continuation_pop + 421
    frame mono/mono#28: 0x65de2ee3 libdispatch.dylib`_dispatch_async_redirect_invoke + 818
    frame mono/mono#29: 0x65df087d libdispatch.dylib`_dispatch_root_queue_drain + 354
    frame mono/mono#30: 0x65df0ff3 libdispatch.dylib`_dispatch_worker_thread2 + 109
    frame mono/mono#31: 0x66024fa0 libsystem_pthread.dylib`_pthread_wqthread + 208
    frame mono/mono#32: 0x66024e44 libsystem_pthread.dylib`start_wqthread + 36
```
which is a thread in a "light" detach state (aka. coop detach), where we only unset the domain:
https://github.com/mono/mono/blob/mono/mono@4cefdcb7ce2d939ee78fb45d1b4913eb3bc064fd/mono/metadata/threads.c#L6084-L6111

Fixes mono/mono#17926

Commit migrated from mono/mono@80b1e10
@fanyang-mono fanyang-mono mentioned this pull request Mar 3, 2020
Closed
picenka21 pushed a commit to picenka21/runtime that referenced this pull request Feb 18, 2022
@akoeplinger
Revert "[marshal] delay dummy string allocation"
6ff8310 
Reverts mono/mono@5e23a77

It seems to cause a crash during msbuild tests:

```
  xunit -> Microsoft.Build.Engine.UnitTests...
  Stacktrace:

  Native stacktrace:

  	0   mono                                0x0017cad4 mono_handle_native_crash + 308
  	1   mono                                0x001e2b03 sigabrt_signal_handler + 147
  	2   libsystem_platform.dylib            0x920a8deb _sigtramp + 43
  	3   ???                                 0xffffffff 0x0 + 4294967295
  	4   libsystem_c.dylib                   0x940bb27c abort + 155
  	5   mono                                0x0036886d mono_log_write_logfile + 381
  	6   mono                                0x003630d2 structured_log_adapter + 50
  	7   mono                                0x00380d1b monoeg_assertion_message + 107
  	8   mono                                0x0033863d major_scan_object_with_evacuation + 3373
  	9   mono                                0x0033b3d0 drain_gray_stack + 6608
  	10  mono                                0x0032df57 finish_gray_stack + 151
  	11  mono                                0x0032d3c6 major_finish_collection + 118
  	12  mono                                0x00329909 major_do_collection + 169
  	13  mono                                0x003288bd sgen_perform_collection + 605
  	14  mono                                0x0032a90b sgen_gc_collect + 75
  	15  mono                                0x002d5c4d unload_thread_main + 861
  	16  mono                                0x002abb6b start_wrapper + 795
  	17  libsystem_pthread.dylib             0x9ae6d5fb _pthread_body + 144
  	18  libsystem_pthread.dylib             0x9ae6d485 _pthread_struct_init + 0
  	19  libsystem_pthread.dylib             0x9ae72cf2 thread_start + 34

  Debug info from gdb:

  (lldb) command source -s 0 '/tmp/mono-gdb-commands.2tso9f'
  Executing commands in '/tmp/mono-gdb-commands.2tso9f'.
  (lldb) process attach --pid 2037
  2017-06-02 13:07:23.000 lldb[2093:282f] Metadata.framework [Error]: couldn't get the client port
  Process 2037 stopped
  * thread mono/mono#1, name = 'tid_507', queue = 'com.apple.main-thread', stop reason = signal SIGSTOP
      frame mono/mono#0: 0x923cc7ca libsystem_kernel.dylib`__psynch_cvwait + 10
  libsystem_kernel.dylib`__psynch_cvwait:
  ->  0x923cc7ca <+10>: jae    0x923cc7da                ; <+26>
      0x923cc7cc <+12>: calll  0x923cc7d1                ; <+17>
      0x923cc7d1 <+17>: popl   %edx
      0x923cc7d2 <+18>: movl   0xe0b084f(%edx), %edx

  Executable module set to "/Users/builder/data/lanes/2716/mono-mac-sdk/external/bockbuild/stage/bin/mono".
  Architecture set to: i386-apple-macosx.
  (lldb) thread list
  Process 2037 stopped
  * thread mono/mono#1: tid = 0x530e96a, 0x923cc7ca libsystem_kernel.dylib`__psynch_cvwait + 10, name = 'tid_507', queue = 'com.apple.main-thread', stop reason = signal SIGSTOP
    thread mono/mono#2: tid = 0x530e96b, 0x923cc7ca libsystem_kernel.dylib`__psynch_cvwait + 10, name = 'SGen worker'
    thread mono/mono#3: tid = 0x530e96c, 0x923cc7ca libsystem_kernel.dylib`__psynch_cvwait + 10, name = 'SGen worker'
    thread mono/mono#4: tid = 0x530e96d, 0x923c7fb6 libsystem_kernel.dylib`semaphore_wait_trap + 10, name = 'Finalizer'
    thread mono/mono#5: tid = 0x530e96e, 0x923cd992 libsystem_kernel.dylib`kevent64 + 10, queue = 'com.apple.libdispatch-manager'
    thread mono/mono#6: tid = 0x530ea26, 0x923ccace libsystem_kernel.dylib`__select + 10, name = 'tid_5a03'
    thread mono/mono#7: tid = 0x530edf1, 0x923cc7ca libsystem_kernel.dylib`__psynch_cvwait + 10, name = 'tid_4007'
    thread mono/mono#8: tid = 0x530edf2, 0x923cc7ca libsystem_kernel.dylib`__psynch_cvwait + 10, name = 'Threadpool worker'
    thread mono/mono#9: tid = 0x530edf3, 0x923cc7ca libsystem_kernel.dylib`__psynch_cvwait + 10, name = 'Threadpool worker'
    thread mono/mono#10: tid = 0x530edf4, 0x923ccff2 libsystem_kernel.dylib`__wait4 + 10, name = 'Domain unloader'
  (lldb) thread backtrace all
  * thread mono/mono#1, name = 'tid_507', queue = 'com.apple.main-thread', stop reason = signal SIGSTOP
    * frame mono/mono#0: 0x923cc7ca libsystem_kernel.dylib`__psynch_cvwait + 10
      frame mono/mono#1: 0x9ae6fd1d libsystem_pthread.dylib`_pthread_cond_wait + 728
      frame mono/mono#2: 0x9ae71bd9 libsystem_pthread.dylib`pthread_cond_wait$UNIX2003 + 71
      frame mono/mono#3: 0x00361ea9 mono`mono_os_event_wait_multiple + 505
      frame mono/mono#4: 0x00361ca5 mono`mono_os_event_wait_one + 53
      frame mono/mono#5: 0x00376b49 mono`mono_thread_info_wait_one_handle + 41
      frame mono/mono#6: 0x002d51b5 mono`mono_domain_try_unload + 485
      frame mono/mono#7: 0x002d4f6a mono`ves_icall_System_AppDomain_InternalUnload + 90
      frame mono/mono#8: 0x05bf9ee0
      frame mono/mono#9: 0x018ce01d mscorlib.dll.dylib`System_AppDomain_Unload_System_AppDomain + 45
      frame mono/mono#10: 0x05bf9d60
      frame mono/mono#11: 0x05bf9ccc
      frame mono/mono#12: 0x05bf9d04
      frame mono/mono#13: 0x05bf9c90
      frame mono/mono#14: 0x05bf996d
      frame mono/mono#15: 0x02e7d171
      frame mono/mono#16: 0x005c26d4
      frame mono/mono#17: 0x005b6878
      frame mono/mono#18: 0x005b6b7a
      frame mono/mono#19: 0x000c38a8 mono`mono_jit_runtime_invoke + 1592
      frame mono/mono#20: 0x002e43fe mono`do_runtime_invoke + 94
      frame mono/mono#21: 0x002e7de3 mono`do_exec_main_checked + 147
      frame mono/mono#22: 0x002e69a5 mono`mono_runtime_run_main_checked + 69
      frame mono/mono#23: 0x0013b687 mono`mono_jit_exec + 311
      frame mono/mono#24: 0x0013e2b2 mono`mono_main + 10114
      frame mono/mono#25: 0x000b22db mono`main + 2011
      frame mono/mono#26: 0x000b1af5 mono`start + 53
    thread mono/mono#2, name = 'SGen worker'
      frame mono/mono#0: 0x923cc7ca libsystem_kernel.dylib`__psynch_cvwait + 10
      frame mono/mono#1: 0x9ae6fd1d libsystem_pthread.dylib`_pthread_cond_wait + 728
      frame mono/mono#2: 0x9ae71bd9 libsystem_pthread.dylib`pthread_cond_wait$UNIX2003 + 71
      frame mono/mono#3: 0x0035f0e9 mono`thread_func + 249
      frame mono/mono#4: 0x9ae6d5fb libsystem_pthread.dylib`_pthread_body + 144
      frame mono/mono#5: 0x9ae6d485 libsystem_pthread.dylib`_pthread_start + 130
      frame mono/mono#6: 0x9ae72cf2 libsystem_pthread.dylib`thread_start + 34
    thread mono/mono#3, name = 'SGen worker'
      frame mono/mono#0: 0x923cc7ca libsystem_kernel.dylib`__psynch_cvwait + 10
      frame mono/mono#1: 0x9ae6fd1d libsystem_pthread.dylib`_pthread_cond_wait + 728
      frame mono/mono#2: 0x9ae71bd9 libsystem_pthread.dylib`pthread_cond_wait$UNIX2003 + 71
      frame mono/mono#3: 0x0035f0e9 mono`thread_func + 249
      frame mono/mono#4: 0x9ae6d5fb libsystem_pthread.dylib`_pthread_body + 144
      frame mono/mono#5: 0x9ae6d485 libsystem_pthread.dylib`_pthread_start + 130
      frame mono/mono#6: 0x9ae72cf2 libsystem_pthread.dylib`thread_start + 34
    thread mono/mono#4, name = 'Finalizer'
      frame mono/mono#0: 0x923c7fb6 libsystem_kernel.dylib`semaphore_wait_trap + 10
      frame mono/mono#1: 0x002dbeb6 mono`finalizer_thread + 278
      frame mono/mono#2: 0x002abb6b mono`start_wrapper + 795
      frame mono/mono#3: 0x9ae6d5fb libsystem_pthread.dylib`_pthread_body + 144
      frame mono/mono#4: 0x9ae6d485 libsystem_pthread.dylib`_pthread_start + 130
      frame mono/mono#5: 0x9ae72cf2 libsystem_pthread.dylib`thread_start + 34
    thread mono/mono#5, queue = 'com.apple.libdispatch-manager'
      frame mono/mono#0: 0x923cd992 libsystem_kernel.dylib`kevent64 + 10
      frame mono/mono#1: 0x91b5c899 libdispatch.dylib`_dispatch_mgr_invoke + 238
      frame mono/mono#2: 0x91b5c532 libdispatch.dylib`_dispatch_mgr_thread + 52
    thread mono/mono#6, name = 'tid_5a03'
      frame mono/mono#0: 0x923ccace libsystem_kernel.dylib`__select + 10
      frame mono/mono#1: 0x0036df29 mono`mono_poll + 409
      frame mono/mono#2: 0x002b482f mono`poll_event_wait + 111
      frame mono/mono#3: 0x002b345f mono`selector_thread + 1439
      frame mono/mono#4: 0x002abb6b mono`start_wrapper + 795
      frame mono/mono#5: 0x9ae6d5fb libsystem_pthread.dylib`_pthread_body + 144
      frame mono/mono#6: 0x9ae6d485 libsystem_pthread.dylib`_pthread_start + 130
      frame mono/mono#7: 0x9ae72cf2 libsystem_pthread.dylib`thread_start + 34
    thread mono/mono#7, name = 'tid_4007'
      frame mono/mono#0: 0x923cc7ca libsystem_kernel.dylib`__psynch_cvwait + 10
      frame mono/mono#1: 0x9ae6fd1d libsystem_pthread.dylib`_pthread_cond_wait + 728
      frame mono/mono#2: 0x9ae71c25 libsystem_pthread.dylib`pthread_cond_timedwait$UNIX2003 + 71
      frame mono/mono#3: 0x003760f3 mono`mono_thread_info_sleep + 979
      frame mono/mono#4: 0x002b1a86 mono`monitor_thread + 262
      frame mono/mono#5: 0x002abb6b mono`start_wrapper + 795
      frame mono/mono#6: 0x9ae6d5fb libsystem_pthread.dylib`_pthread_body + 144
      frame mono/mono#7: 0x9ae6d485 libsystem_pthread.dylib`_pthread_start + 130
      frame mono/mono#8: 0x9ae72cf2 libsystem_pthread.dylib`thread_start + 34
    thread mono/mono#8, name = 'Threadpool worker'
      frame mono/mono#0: 0x923cc7ca libsystem_kernel.dylib`__psynch_cvwait + 10
      frame mono/mono#1: 0x9ae6fd1d libsystem_pthread.dylib`_pthread_cond_wait + 728
      frame mono/mono#2: 0x9ae71c25 libsystem_pthread.dylib`pthread_cond_timedwait$UNIX2003 + 71
      frame mono/mono#3: 0x002b12e0 mono`worker_thread + 1024
      frame mono/mono#4: 0x002abb6b mono`start_wrapper + 795
      frame mono/mono#5: 0x9ae6d5fb libsystem_pthread.dylib`_pthread_body + 144
      frame mono/mono#6: 0x9ae6d485 libsystem_pthread.dylib`_pthread_start + 130
      frame mono/mono#7: 0x9ae72cf2 libsystem_pthread.dylib`thread_start + 34
    thread mono/mono#9, name = 'Threadpool worker'
      frame mono/mono#0: 0x923cc7ca libsystem_kernel.dylib`__psynch_cvwait + 10
      frame mono/mono#1: 0x9ae6fd1d libsystem_pthread.dylib`_pthread_cond_wait + 728
      frame mono/mono#2: 0x9ae71c25 libsystem_pthread.dylib`pthread_cond_timedwait$UNIX2003 + 71
      frame mono/mono#3: 0x002b12e0 mono`worker_thread + 1024
      frame mono/mono#4: 0x002abb6b mono`start_wrapper + 795
      frame mono/mono#5: 0x9ae6d5fb libsystem_pthread.dylib`_pthread_body + 144
      frame mono/mono#6: 0x9ae6d485 libsystem_pthread.dylib`_pthread_start + 130
      frame mono/mono#7: 0x9ae72cf2 libsystem_pthread.dylib`thread_start + 34
    thread mono/mono#10, name = 'Domain unloader'
      frame mono/mono#0: 0x923ccff2 libsystem_kernel.dylib`__wait4 + 10
      frame mono/mono#1: 0x940d9ea5 libsystem_c.dylib`waitpid$UNIX2003 + 48
      frame mono/mono#2: 0x0017cba7 mono`mono_handle_native_crash + 519
      frame mono/mono#3: 0x001e2b03 mono`sigabrt_signal_handler + 147
      frame mono/mono#4: 0x920a8deb libsystem_platform.dylib`_sigtramp + 43
  (lldb) detach
  Process 2037 detached
  (lldb) quit

  =================================================================
  Got a SIGABRT while executing native code. This usually indicates
  a fatal error in the mono runtime or one of the native libraries
  used by your application.
  =================================================================
```


Commit migrated from mono/mono@d30c17f
@jbatt33 jbatt33 mentioned this pull request Sep 12, 2023
Open
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@djsell