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relaxable mov rd,#immx #6

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olajep opened this issue Oct 1, 2015 · 1 comment
Open

relaxable mov rd,#immx #6

olajep opened this issue Oct 1, 2015 · 1 comment

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@olajep
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olajep commented Oct 1, 2015

Currently, this:

.text
_start:
    mov r0, foo

.data
.align 3
foo:
.word 0x12345678

...fails with

(.text+0x0): relocation truncated to fit: R_EPIPHANY_16 against `no symbol'

It would be nice to have a relaxable mov that expanded (if needed) to:

    mov r0, %low(foo)
    movt ro,%high(foo)
olajep pushed a commit that referenced this issue Nov 10, 2016
If I build gdb with -fsanitize=address and run tests, I get error,

malformed linespec error: unexpected colon^M
(gdb) PASS: gdb.linespec/ls-errs.exp: lang=C: break     :
break   :=================================================================^M
==3266==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x602000051451 at pc 0x2b5797a972a8 bp 0x7fffd8e0f3c0 sp 0x7fffd8e0f398^M
READ of size 2 at 0x602000051451 thread T0
    #0 0x2b5797a972a7 in __interceptor_strlen (/usr/lib/x86_64-linux-gnu/libasan.so.1+0x322a7)^M
    #1 0x7bd004 in compare_filenames_for_search(char const*, char const*) /home/yao/SourceCode/gnu/gdb/git/gdb/symtab.c:316^M
    #2 0x7bd310 in iterate_over_some_symtabs(char const*, char const*, int (*)(symtab*, void*), void*, compunit_symtab*, compunit_symtab*) /home/yao/SourceCode/gnu/gdb/git/gdb/symtab.c:411^M
    #3 0x7bd775 in iterate_over_symtabs(char const*, int (*)(symtab*, void*), void*) /home/yao/SourceCode/gnu/gdb/git/gdb/symtab.c:481^M
    #4 0x7bda15 in lookup_symtab(char const*) /home/yao/SourceCode/gnu/gdb/git/gdb/symtab.c:527^M
    #5 0x7d5e2a in make_file_symbol_completion_list_1 /home/yao/SourceCode/gnu/gdb/git/gdb/symtab.c:5635^M
    #6 0x7d61e1 in make_file_symbol_completion_list(char const*, char const*, char const*) /home/yao/SourceCode/gnu/gdb/git/gdb/symtab.c:5684^M
    #7 0x88dc06 in linespec_location_completer /home/yao/SourceCode/gnu/gdb/git/gdb/completer.c:288
....
0x602000051451 is located 0 bytes to the right of 1-byte region [0x602000051450,0x602000051451)^M
mallocated by thread T0 here:
    #0 0x2b5797ab97ef in __interceptor_malloc (/usr/lib/x86_64-linux-gnu/libasan.so.1+0x547ef)^M
    #1 0xbbfb8d in xmalloc /home/yao/SourceCode/gnu/gdb/git/gdb/common/common-utils.c:43^M
    #2 0x88dabd in linespec_location_completer /home/yao/SourceCode/gnu/gdb/git/gdb/completer.c:273^M
    #3 0x88e5ef in location_completer(cmd_list_element*, char const*, char const*) /home/yao/SourceCode/gnu/gdb/git/gdb/completer.c:531^M
    #4 0x8902e7 in complete_line_internal /home/yao/SourceCode/gnu/gdb/git/gdb/completer.c:964^

The code in question is here

       file_to_match = (char *) xmalloc (colon - text + 1);
       strncpy (file_to_match, text, colon - text + 1);

it is likely that file_to_match is not null-terminated.  The patch is
to strncpy 'colon - text' bytes and explicitly set '\0'.

gdb:

2016-08-19  Yao Qi  <yao.qi@linaro.org>

	* completer.c (linespec_location_completer): Make file_to_match
	null-terminated.
olajep pushed a commit that referenced this issue Nov 10, 2016
Most of the time, the trace should be in one piece.  This case is handled fine
by GDB.  In some cases, however, there may be gaps in the trace.  They result
from trace decode errors or from overflows.

A gap in the trace means we lost an unknown amount of trace.  Gaps can be very
small, such as a few instructions in the same function, or they can be rather
big.  We may, for example, lose a few function calls or returns.  The trace may
continue in a different function and we likely don't know how we got there.

Even though we can't say how the program executed across a gap, higher levels
may not be impacted too much by it.  Let's assume we have functions a-e and a
trace that looks roughly like this:

  a
   \
    b                    b
     \                  /
      c   <gap>        c
                      /
                 d   d
                  \ /
                   e

Even though we can't say for sure, it is likely that b and c are the same
function instance before and after the gap.  This patch is trying to connect
the c and b function segments across the gap.

This will add a to the back trace of b on the right hand side.  The changes are
reflected in GDB's internal representation of the trace and will improve:

  - the output of "record function-call-history /c"
  - the output of "backtrace" in replay mode
  - source stepping in replay mode
    will be improved indirectly via the improved back trace

I don't have an automated test for this patch; decode errors will be fixed and
overflows occur sporadically and are quite rare.  I tested it by hacking GDB to
provoke a decode error and on the expected gap in the gdb.btrace/dlopen.exp
test.

The issue is that we can't predict where we will be able to re-sync in case of
errors.  For the expected decode error in gdb.btrace/dlopen.exp, for example, we
may be able to re-sync somewhere in dlclose, in test, in main, or not at all.

Here's one example run of gdb.btrace/dlopen.exp with and without this patch.

    (gdb) info record
    Active record target: record-btrace
    Recording format: Intel Processor Trace.
    Buffer size: 16kB.
    warning: Non-contiguous trace at instruction 66608 (offset = 0xa83, pc = 0xb7fdcc31).
    warning: Non-contiguous trace at instruction 66652 (offset = 0xa9b, pc = 0xb7fdcc31).
    warning: Non-contiguous trace at instruction 66770 (offset = 0xacb, pc = 0xb7fdcc31).
    warning: Non-contiguous trace at instruction 66966 (offset = 0xb60, pc = 0xb7ff5ee4).
    warning: Non-contiguous trace at instruction 66994 (offset = 0xb74, pc = 0xb7ff5f24).
    warning: Non-contiguous trace at instruction 67334 (offset = 0xbac, pc = 0xb7ff5e6d).
    warning: Non-contiguous trace at instruction 69022 (offset = 0xc04, pc = 0xb7ff60b3).
    warning: Non-contiguous trace at instruction 69116 (offset = 0xc1c, pc = 0xb7ff60b3).
    warning: Non-contiguous trace at instruction 69504 (offset = 0xc74, pc = 0xb7ff605d).
    warning: Non-contiguous trace at instruction 83648 (offset = 0xecc, pc = 0xb7ff6134).
    warning: Decode error (-13) at instruction 83876 (offset = 0xf48, pc = 0xb7fd6380): no memory mapped at this address.
    warning: Non-contiguous trace at instruction 83876 (offset = 0x11b7, pc = 0xb7ff1c70).
    Recorded 83948 instructions in 912 functions (12 gaps) for thread 1 (process 12996).
    (gdb) record instruction-history 83876, +2
    83876   => 0xb7fec46f <call_init.part.0+95>:    call   *%eax
    [decode error (-13): no memory mapped at this address]
    [disabled]
    83877      0xb7ff1c70 <_dl_close_worker.part.0+1584>:   nop

Without the patch, the trace is disconnected and the backtrace is short:

    (gdb) record goto 83876
    #0  0xb7fec46f in call_init.part () from /lib/ld-linux.so.2
    (gdb) backtrace
    #0  0xb7fec46f in call_init.part () from /lib/ld-linux.so.2
    #1  0xb7fec5d0 in _dl_init () from /lib/ld-linux.so.2
    #2  0xb7ff0fe3 in dl_open_worker () from /lib/ld-linux.so.2
    Backtrace stopped: not enough registers or memory available to unwind further
    (gdb) record goto 83877
    #0  0xb7ff1c70 in _dl_close_worker.part.0 () from /lib/ld-linux.so.2
    (gdb) backtrace
    #0  0xb7ff1c70 in _dl_close_worker.part.0 () from /lib/ld-linux.so.2
    #1  0xb7ff287a in _dl_close () from /lib/ld-linux.so.2
    #2  0xb7fc3d5d in dlclose_doit () from /lib/libdl.so.2
    #3  0xb7fec354 in _dl_catch_error () from /lib/ld-linux.so.2
    #4  0xb7fc43dd in _dlerror_run () from /lib/libdl.so.2
    #5  0xb7fc3d98 in dlclose () from /lib/libdl.so.2
    #6  0x0804860a in test ()
    #7  0x08048628 in main ()

With the patch, GDB is able to connect the trace pieces and we get a full
backtrace.

    (gdb) record goto 83876
    #0  0xb7fec46f in call_init.part () from /lib/ld-linux.so.2
    (gdb) backtrace
    #0  0xb7fec46f in call_init.part () from /lib/ld-linux.so.2
    #1  0xb7fec5d0 in _dl_init () from /lib/ld-linux.so.2
    #2  0xb7ff0fe3 in dl_open_worker () from /lib/ld-linux.so.2
    #3  0xb7fec354 in _dl_catch_error () from /lib/ld-linux.so.2
    #4  0xb7ff02e2 in _dl_open () from /lib/ld-linux.so.2
    #5  0xb7fc3c65 in dlopen_doit () from /lib/libdl.so.2
    #6  0xb7fec354 in _dl_catch_error () from /lib/ld-linux.so.2
    #7  0xb7fc43dd in _dlerror_run () from /lib/libdl.so.2
    #8  0xb7fc3d0e in dlopen@@GLIBC_2.1 () from /lib/libdl.so.2
    #9  0xb7ff28ee in _dl_runtime_resolve () from /lib/ld-linux.so.2
    #10 0x0804841c in ?? ()
    #11 0x08048470 in dlopen@plt ()
    #12 0x080485a3 in test ()
    #13 0x08048628 in main ()
    (gdb) record goto 83877
    #0  0xb7ff1c70 in _dl_close_worker.part.0 () from /lib/ld-linux.so.2
    (gdb) backtrace
    #0  0xb7ff1c70 in _dl_close_worker.part.0 () from /lib/ld-linux.so.2
    #1  0xb7ff287a in _dl_close () from /lib/ld-linux.so.2
    #2  0xb7fc3d5d in dlclose_doit () from /lib/libdl.so.2
    #3  0xb7fec354 in _dl_catch_error () from /lib/ld-linux.so.2
    #4  0xb7fc43dd in _dlerror_run () from /lib/libdl.so.2
    #5  0xb7fc3d98 in dlclose () from /lib/libdl.so.2
    #6  0x0804860a in test ()
    #7  0x08048628 in main ()

It worked nicely in this case but it may, of course, also lead to weird
connections; it is a heuristic, after all.

It works best when the gap is small and the trace pieces are long.

gdb/
	* btrace.c (bfun_s): New typedef.
	(ftrace_update_caller): Print caller in debug dump.
	(ftrace_get_caller, ftrace_match_backtrace, ftrace_fixup_level)
	(ftrace_compute_global_level_offset, ftrace_connect_bfun)
	(ftrace_connect_backtrace, ftrace_bridge_gap, btrace_bridge_gaps): New.
	(btrace_compute_ftrace_bts): Pass vector of gaps.  Collect gaps.
	(btrace_compute_ftrace_pt): Likewise.
	(btrace_compute_ftrace): Split into this, ...
	(btrace_compute_ftrace_1): ... this, and ...
	(btrace_finalize_ftrace): ... this.  Call btrace_bridge_gaps.
olajep pushed a commit that referenced this issue Mar 25, 2019
…b/23379)

This commit fixes a 8.1->8.2 regression exposed by
gdb.python/py-evthreads.exp when testing with
--target_board=native-gdbserver.

gdb.log shows:

  src/gdb/thread.c:93: internal-error: thread_info* inferior_thread(): Assertion `tp' failed.
  A problem internal to GDB has been detected,
  further debugging may prove unreliable.
  Quit this debugging session? (y or n) FAIL: gdb.python/py-evthreads.exp: run to breakpoint 1 (GDB internal error)

A backtrace shows (frames #2 and #10 highlighted) that the assertion
fails when GDB is setting up the connection to the remote target, in
non-stop mode:

  #0  0x0000000000622ff0 in internal_error(char const*, int, char const*, ...) (file=0xc1ad98 "src/gdb/thread.c", line=93, fmt=0xc1ad20 "%s: Assertion `%s' failed.") at src/gdb/common/errors.c:54
  #1  0x000000000089567e in inferior_thread() () at src/gdb/thread.c:93
= #2  0x00000000004da91d in get_event_thread() () at src/gdb/python/py-threadevent.c:38
  #3  0x00000000004da9b7 in create_thread_event_object(_typeobject*, _object*) (py_type=0x11574c0 <continue_event_object_type>, thread=0x0)
      at src/gdb/python/py-threadevent.c:60
  #4  0x00000000004bf6fe in create_continue_event_object() () at src/gdb/python/py-continueevent.c:27
  #5  0x00000000004bf738 in emit_continue_event(ptid_t) (ptid=...) at src/gdb/python/py-continueevent.c:40
  #6  0x00000000004c7d47 in python_on_resume(ptid_t) (ptid=...) at src/gdb/python/py-inferior.c:108
  #7  0x0000000000485bfb in std::_Function_handler<void (ptid_t), void (*)(ptid_t)>::_M_invoke(std::_Any_data const&, ptid_t&&) (__functor=..., __args#0=...) at /usr/include/c++/7/bits/std_function.h:316
  #8  0x000000000089b416 in std::function<void (ptid_t)>::operator()(ptid_t) const (this=0x12aa600, __args#0=...)
      at /usr/include/c++/7/bits/std_function.h:706
  #9  0x000000000089aa0e in gdb::observers::observable<ptid_t>::notify(ptid_t) const (this=0x118a7a0 <gdb::observers::target_resumed>, args#0=...)
      at src/gdb/common/observable.h:106
= #10 0x0000000000896fbe in set_running(ptid_t, int) (ptid=..., running=1) at src/gdb/thread.c:880
  #11 0x00000000007f750f in remote_target::remote_add_thread(ptid_t, bool, bool) (this=0x12c5440, ptid=..., running=true, executing=true) at src/gdb/remote.c:2434
  #12 0x00000000007f779d in remote_target::remote_notice_new_inferior(ptid_t, int) (this=0x12c5440, currthread=..., executing=1)
      at src/gdb/remote.c:2515
  #13 0x00000000007f9c44 in remote_target::update_thread_list() (this=0x12c5440) at src/gdb/remote.c:3831
  #14 0x00000000007fb922 in remote_target::start_remote(int, int) (this=0x12c5440, from_tty=0, extended_p=0)
      at src/gdb/remote.c:4655
  #15 0x00000000007fd102 in remote_target::open_1(char const*, int, int) (name=0x1a4f45e "localhost:2346", from_tty=0, extended_p=0)
      at src/gdb/remote.c:5638
  #16 0x00000000007fbec1 in remote_target::open(char const*, int) (name=0x1a4f45e "localhost:2346", from_tty=0)
      at src/gdb/remote.c:4862

So on frame #10, we're marking a newly-discovered thread as running,
and that causes the Python API to emit a gdb.ContinueEvent.
gdb.ContinueEvent is a gdb.ThreadEvent, and as such includes the event
thread as the "inferior_thread" attribute.  The problem is that when
we get to frame #3/#4, we lost all references to the thread that is
being marked as running.  create_continue_event_object assumes that it
is the current thread, which is not true in this case.

Fix this by passing down the right thread in
create_continue_event_object.  Also remove
create_thread_event_object's default argument and have the only other
caller left pass down the right thread explicitly too.

gdb/ChangeLog:
2018-08-24  Pedro Alves  <palves@redhat.com>
	    Simon Marchi  <simon.marchi@ericsson.com>

	PR gdb/23379
	* python/py-continueevent.c: Include "gdbthread.h".
	(create_continue_event_object): Add intro comment.  Add 'ptid'
	parameter.  Use it to find thread to pass to
	create_thread_event_object.
	(emit_continue_event): Pass PTID down to
	create_continue_event_object.
	* python/py-event.h (py_get_event_thread): Declare.
	(create_thread_event_object): Remove default from 'thread'
	parameter.
	* python/py-stopevent.c (create_stop_event_object): Use
	py_get_event_thread.
	* python/py-threadevent.c (get_event_thread): Rename to ...
	(py_get_event_thread): ... this, make extern, add 'ptid' parameter
	and use it to find the thread.
	(create_thread_event_object): Assert that THREAD isn't null.
	Don't find the event thread here.
@nickl-
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nickl- commented Jul 12, 2019

Commits incorrectly reference this issue because of debug output in message.

olajep pushed a commit to olajep/epiphany-binutils-gdb that referenced this issue Oct 16, 2022
…nd crashes readline/GDB

Jan caught an intermittent GDB crash with the annota1.exp test:

 Starting program: .../gdb/testsuite/gdb.base/annota1 ^M
 [...]
 FAIL: gdb.base/annota1.exp: run until main breakpoint (timeout)
 [...]
 readline: readline_callback_read_char() called with no handler!^M
 ERROR: Process no longer exists

All we need to is to continue the inferior in the foreground, and type
a command while the inferior is running.  E.g.:

 (gdb) set annotate 2

 ▒▒pre-prompt
 (gdb)
 ▒▒prompt
 c

 ▒▒post-prompt
 Continuing.

 ▒▒starting

 ▒▒frames-invalid

 *inferior is running now*

 p 1<ret>

 readline: readline_callback_read_char() called with no handler!
 Aborted (core dumped)
 $


When we run a foreground execution command we call
target_terminal_inferior to stop GDB from processing input, and to put
the inferior's terminal settings in effect.  Then we tell readline to
hide the prompt with display_gdb_prompt, which clears readline's input
callback too.  When the target stops, we call target_terminal_ours,
which re-installs stdin in the event loop, and then we redisplay the
prompt, reinstalling the readline callbacks.

However, when annotations are in effect, the "frames-invalid"
annotation code calls target_terminal_ours after 'resume' had already
called target_terminal_inferior:

 (top-gdb) bt
 #0  0x000000000056b82f in annotate_frames_invalid () at gdb/annotate.c:219
 adapteva#1  0x000000000072e6cc in reinit_frame_cache () at gdb/frame.c:1705
 adapteva#2  0x0000000000594bb9 in registers_changed_ptid (ptid=...) at gdb/regcache.c:612
 adapteva#3  0x000000000064cca1 in target_resume (ptid=..., step=1, signal=GDB_SIGNAL_0) at gdb/target.c:2136
 adapteva#4  0x00000000005f57af in resume (step=1, sig=GDB_SIGNAL_0) at gdb/infrun.c:2263
 adapteva#5  0x00000000005f6051 in proceed (addr=18446744073709551615, siggnal=GDB_SIGNAL_DEFAULT, step=1) at gdb/infrun.c:2613

And then once we hide the prompt and remove readline's input handler
callback, we're in a bad state.  We end up with the target running
supposedly in the foreground, but with stdin still installed on the
event loop.  Any input then calls into readline, which aborts because
no rl_linefunc callback handler is installed:

 Program received signal SIGABRT, Aborted.
 0x0000003b36a35877 in __GI_raise (sig=sig@entry=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:56
 56        return INLINE_SYSCALL (tgkill, 3, pid, selftid, sig);

 (top-gdb) bt
 #0  0x0000003b36a35877 in __GI_raise (sig=sig@entry=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:56
 adapteva#1  0x0000003b36a36f68 in __GI_abort () at abort.c:89
 During symbol reading, debug info gives source 9 included from file at zero line 0.
 During symbol reading, debug info gives command-line macro definition with non-zero line 19: _STDC_PREDEF_H 1.
 adapteva#2  0x0000000000784a25 in rl_callback_read_char () at src/readline/callback.c:116
 adapteva#3  0x0000000000619111 in rl_callback_read_char_wrapper (client_data=0x0) at src/gdb/event-top.c:167
 adapteva#4  0x00000000006194e7 in stdin_event_handler (error=0, client_data=0x0) at src/gdb/event-top.c:373
 adapteva#5  0x00000000006180da in handle_file_event (data=...) at src/gdb/event-loop.c:763
 adapteva#6  0x00000000006175c1 in process_event () at src/gdb/event-loop.c:340
 adapteva#7  0x0000000000617688 in gdb_do_one_event () at src/gdb/event-loop.c:404
 adapteva#8  0x00000000006176d8 in start_event_loop () at src/gdb/event-loop.c:429
 adapteva#9  0x0000000000619143 in cli_command_loop (data=0x0) at src/gdb/event-top.c:182
 adapteva#10 0x000000000060f4c8 in current_interp_command_loop () at src/gdb/interps.c:318
 adapteva#11 0x0000000000610691 in captured_command_loop (data=0x0) at src/gdb/main.c:323
 #12 0x000000000060c385 in catch_errors (func=0x610676 <captured_command_loop>, func_args=0x0, errstring=0x900241 "", mask=RETURN_MASK_ALL)
     at src/gdb/exceptions.c:237
 #13 0x0000000000611b8f in captured_main (data=0x7fffffffd7b0) at src/gdb/main.c:1151
 #14 0x000000000060c385 in catch_errors (func=0x610a8e <captured_main>, func_args=0x7fffffffd7b0, errstring=0x900241 "", mask=RETURN_MASK_ALL)
     at src/gdb/exceptions.c:237
 #15 0x0000000000611bb8 in gdb_main (args=0x7fffffffd7b0) at src/gdb/main.c:1159
 #16 0x000000000045ef57 in main (argc=3, argv=0x7fffffffd8b8) at src/gdb/gdb.c:32

The fix is to make the annotation code call target_terminal_inferior
again after printing, if the inferior's settings were in effect.

While at it, when we're doing output only, instead of
target_terminal_ours, we should call target_terminal_ours_for_output.
The latter doesn't actually remove stdin from the event loop, and also
leaves SIGINT forwarded to the target.

New test included.

Tested on x86_64 Fedora 20, native and gdbserver.

gdb/
2014-10-17  Pedro Alves  <palves@redhat.com>

	PR gdb/17472
	* annotate.c (annotate_breakpoints_invalid): Use
	target_terminal_our_for_output instead of target_terminal_ours.
	Give back the terminal to the target.
	(annotate_frames_invalid): Likewise.

gdb/testsuite/
2014-10-17  Pedro Alves  <palves@redhat.com>

	PR gdb/17472
	* gdb.base/annota-input-while-running.c: New file.
	* gdb.base/annota-input-while-running.exp: New file.
olajep pushed a commit to olajep/epiphany-binutils-gdb that referenced this issue Oct 16, 2022
If all threads in the target were already running when the user does
"c -a", nothing puts the inferior's terminal settings in effect and
removes stdin from the event loop, which we must when running a
foreground command.  The result is that user input afterwards crashes
readline/gdb:

 (gdb) start
 Temporary breakpoint 1 at 0x4005d4: file continue-all-already-running.c, line 23.
 Starting program: continue-all-already-running

 Temporary breakpoint 1, main () at continue-all-already-running.c:23
 23        sleep (10);
 (gdb) c -a&
 Continuing.
 (gdb) c -a
 Continuing.
 p 1
 readline: readline_callback_read_char() called with no handler!
 Aborted (core dumped)
 $

Backtrace:

 Program received signal SIGABRT, Aborted.
 0x0000003b36a35877 in __GI_raise (sig=sig@entry=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:56
 56        return INLINE_SYSCALL (tgkill, 3, pid, selftid, sig);
 (top-gdb) p 1
 $1 = 1
 (top-gdb) bt
 #0  0x0000003b36a35877 in __GI_raise (sig=sig@entry=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:56
 adapteva#1  0x0000003b36a36f68 in __GI_abort () at abort.c:89
 adapteva#2  0x0000000000784aa9 in rl_callback_read_char () at readline/callback.c:116
 adapteva#3  0x0000000000619181 in rl_callback_read_char_wrapper (client_data=0x0) at gdb/event-top.c:167
 adapteva#4  0x0000000000619557 in stdin_event_handler (error=0, client_data=0x0) at gdb/event-top.c:373
 adapteva#5  0x000000000061814a in handle_file_event (data=...) at gdb/event-loop.c:763
 adapteva#6  0x0000000000617631 in process_event () at gdb/event-loop.c:340
 adapteva#7  0x00000000006176f8 in gdb_do_one_event () at gdb/event-loop.c:404
 adapteva#8  0x0000000000617748 in start_event_loop () at gdb/event-loop.c:429
 adapteva#9  0x00000000006191b3 in cli_command_loop (data=0x0) at gdb/event-top.c:182
 adapteva#10 0x000000000060f538 in current_interp_command_loop () at gdb/interps.c:318
 adapteva#11 0x0000000000610701 in captured_command_loop (data=0x0) at gdb/main.c:323
 #12 0x000000000060c3f5 in catch_errors (func=0x6106e6 <captured_command_loop>, func_args=0x0, errstring=0x9002c1 "", mask=RETURN_MASK_ALL)
     at gdb/exceptions.c:237
 #13 0x0000000000611bff in captured_main (data=0x7fffffffd780) at gdb/main.c:1151
 #14 0x000000000060c3f5 in catch_errors (func=0x610afe <captured_main>, func_args=0x7fffffffd780, errstring=0x9002c1 "", mask=RETURN_MASK_ALL)
     at gdb/exceptions.c:237
 #15 0x0000000000611c28 in gdb_main (args=0x7fffffffd780) at gdb/main.c:1159
 #16 0x000000000045ef97 in main (argc=5, argv=0x7fffffffd888) at gdb/gdb.c:32
 (top-gdb)

Tested on x86_64 Fedora 20, native and gdbserver.

gdb/
2014-10-17  Pedro Alves  <palves@redhat.com>

	PR gdb/17300
	* infcmd.c (continue_1): If continuing all threads in the
	foreground, make sure the inferior's terminal settings are put in
	effect.

gdb/testsuite/
2014-10-17  Pedro Alves  <palves@redhat.com>

	PR gdb/17300
	* gdb.base/continue-all-already-running.c: New file.
	* gdb.base/continue-all-already-running.exp: New file.
olajep pushed a commit to olajep/epiphany-binutils-gdb that referenced this issue Oct 16, 2022
If I build gdb with -fsanitize=address and run tests, I get error,

malformed linespec error: unexpected colon^M
(gdb) PASS: gdb.linespec/ls-errs.exp: lang=C: break     :
break   :=================================================================^M
==3266==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x602000051451 at pc 0x2b5797a972a8 bp 0x7fffd8e0f3c0 sp 0x7fffd8e0f398^M
READ of size 2 at 0x602000051451 thread T0
    #0 0x2b5797a972a7 in __interceptor_strlen (/usr/lib/x86_64-linux-gnu/libasan.so.1+0x322a7)^M
    adapteva#1 0x7bd004 in compare_filenames_for_search(char const*, char const*) /home/yao/SourceCode/gnu/gdb/git/gdb/symtab.c:316^M
    adapteva#2 0x7bd310 in iterate_over_some_symtabs(char const*, char const*, int (*)(symtab*, void*), void*, compunit_symtab*, compunit_symtab*) /home/yao/SourceCode/gnu/gdb/git/gdb/symtab.c:411^M
    adapteva#3 0x7bd775 in iterate_over_symtabs(char const*, int (*)(symtab*, void*), void*) /home/yao/SourceCode/gnu/gdb/git/gdb/symtab.c:481^M
    adapteva#4 0x7bda15 in lookup_symtab(char const*) /home/yao/SourceCode/gnu/gdb/git/gdb/symtab.c:527^M
    adapteva#5 0x7d5e2a in make_file_symbol_completion_list_1 /home/yao/SourceCode/gnu/gdb/git/gdb/symtab.c:5635^M
    adapteva#6 0x7d61e1 in make_file_symbol_completion_list(char const*, char const*, char const*) /home/yao/SourceCode/gnu/gdb/git/gdb/symtab.c:5684^M
    adapteva#7 0x88dc06 in linespec_location_completer /home/yao/SourceCode/gnu/gdb/git/gdb/completer.c:288
....
0x602000051451 is located 0 bytes to the right of 1-byte region [0x602000051450,0x602000051451)^M
mallocated by thread T0 here:
    #0 0x2b5797ab97ef in __interceptor_malloc (/usr/lib/x86_64-linux-gnu/libasan.so.1+0x547ef)^M
    adapteva#1 0xbbfb8d in xmalloc /home/yao/SourceCode/gnu/gdb/git/gdb/common/common-utils.c:43^M
    adapteva#2 0x88dabd in linespec_location_completer /home/yao/SourceCode/gnu/gdb/git/gdb/completer.c:273^M
    adapteva#3 0x88e5ef in location_completer(cmd_list_element*, char const*, char const*) /home/yao/SourceCode/gnu/gdb/git/gdb/completer.c:531^M
    adapteva#4 0x8902e7 in complete_line_internal /home/yao/SourceCode/gnu/gdb/git/gdb/completer.c:964^

The code in question is here

       file_to_match = (char *) xmalloc (colon - text + 1);
       strncpy (file_to_match, text, colon - text + 1);

it is likely that file_to_match is not null-terminated.  The patch is
to strncpy 'colon - text' bytes and explicitly set '\0'.

gdb:

2016-08-19  Yao Qi  <yao.qi@linaro.org>

	* completer.c (linespec_location_completer): Make file_to_match
	null-terminated.
olajep pushed a commit to olajep/epiphany-binutils-gdb that referenced this issue Oct 16, 2022
When loading a file using the file command on macOS, we get:

    $ ./gdb -nx --data-directory=data-directory -q -ex "file ./test"
    Reading symbols from ./test...
    Reading symbols from /Users/smarchi/build/binutils-gdb/gdb/test.dSYM/Contents/Resources/DWARF/test...
    /Users/smarchi/src/binutils-gdb/gdb/thread.c:72: internal-error: struct thread_info *inferior_thread(): Assertion `current_thread_ != nullptr' failed.
    A problem internal to GDB has been detected,
    further debugging may prove unreliable.
    Quit this debugging session? (y or n)

The backtrace is:

    * frame #0: 0x0000000101fcb826 gdb`internal_error(file="/Users/smarchi/src/binutils-gdb/gdb/thread.c", line=72, fmt="%s: Assertion `%s' failed.") at errors.cc:52:3
      frame adapteva#1: 0x00000001018a2584 gdb`inferior_thread() at thread.c:72:3
      frame adapteva#2: 0x0000000101469c09 gdb`get_current_regcache() at regcache.c:421:31
      frame adapteva#3: 0x00000001015f9812 gdb`darwin_solib_get_all_image_info_addr_at_init(info=0x0000603000006d00) at solib-darwin.c:464:34
      frame adapteva#4: 0x00000001015f7a04 gdb`darwin_solib_create_inferior_hook(from_tty=1) at solib-darwin.c:515:5
      frame adapteva#5: 0x000000010161205e gdb`solib_create_inferior_hook(from_tty=1) at solib.c:1200:3
      frame adapteva#6: 0x00000001016d8f76 gdb`symbol_file_command(args="./test", from_tty=1) at symfile.c:1650:7
      frame adapteva#7: 0x0000000100abab17 gdb`file_command(arg="./test", from_tty=1) at exec.c:555:3
      frame adapteva#8: 0x00000001004dc799 gdb`do_const_cfunc(c=0x000061100000c340, args="./test", from_tty=1) at cli-decode.c:102:3
      frame adapteva#9: 0x00000001004ea042 gdb`cmd_func(cmd=0x000061100000c340, args="./test", from_tty=1) at cli-decode.c:2160:7
      frame adapteva#10: 0x00000001018d4f59 gdb`execute_command(p="t", from_tty=1) at top.c:674:2
      frame adapteva#11: 0x0000000100eee430 gdb`catch_command_errors(command=(gdb`execute_command(char const*, int) at top.c:561), arg="file ./test", from_tty=1, do_bp_actions=true)(char const*, int), char const*, int, bool) at main.c:523:7
      frame #12: 0x0000000100eee902 gdb`execute_cmdargs(cmdarg_vec=0x00007ffeefbfeba0 size=1, file_type=CMDARG_FILE, cmd_type=CMDARG_COMMAND, ret=0x00007ffeefbfec20) at main.c:618:9
      frame #13: 0x0000000100eed3a4 gdb`captured_main_1(context=0x00007ffeefbff780) at main.c:1322:3
      frame #14: 0x0000000100ee810d gdb`captured_main(data=0x00007ffeefbff780) at main.c:1343:3
      frame #15: 0x0000000100ee8025 gdb`gdb_main(args=0x00007ffeefbff780) at main.c:1368:7
      frame #16: 0x00000001000044f1 gdb`main(argc=6, argv=0x00007ffeefbff8a0) at gdb.c:32:10
      frame #17: 0x00007fff20558f5d libdyld.dylib`start + 1

The solib_create_inferior_hook call in symbol_file_command was added by
commit ea142fb ("Fix breakpoints on file reloads for PIE
binaries").  It causes solib_create_inferior_hook to be called while
the inferior is not running, which darwin_solib_create_inferior_hook
does not expect.  darwin_solib_get_all_image_info_addr_at_init, in
particular, assumes that there is a current thread, as it tries to get
the current thread's regcache.

Fix it by adding a target_has_execution check and returning early.  Note
that there is a similar check in svr4_solib_create_inferior_hook.

gdb/ChangeLog:

	* solib-darwin.c (darwin_solib_create_inferior_hook): Return
	early if no execution.

Change-Id: Ia11dd983a1e29786e5ce663d0fcaa6846dc611bb
olajep pushed a commit to olajep/epiphany-binutils-gdb that referenced this issue Oct 16, 2022
Commit 408f668 ("detach in all-stop
with threads running") regressed "detach" with "target remote":

 (gdb) detach
 Detaching from program: target:/any/program, process 3671843
 Detaching from process 3671843
 Ending remote debugging.
 [Inferior 1 (process 3671843) detached]
 In main
 terminate called after throwing an instance of 'gdb_exception_error'
 Aborted (core dumped)

Here's the exception above being thrown:

 (top-gdb) bt
 #0  throw_error (error=TARGET_CLOSE_ERROR, fmt=0x555556035588 "Remote connection closed") at src/gdbsupport/common-exceptions.cc:222
 adapteva#1  0x0000555555bbaa46 in remote_target::readchar (this=0x555556a11040, timeout=10000) at src/gdb/remote.c:9440
 adapteva#2  0x0000555555bbb9e5 in remote_target::getpkt_or_notif_sane_1 (this=0x555556a11040, buf=0x555556a11058, forever=0, expecting_notif=0, is_notif=0x0) at src/gdb/remote.c:9928
 adapteva#3  0x0000555555bbbda9 in remote_target::getpkt_sane (this=0x555556a11040, buf=0x555556a11058, forever=0) at src/gdb/remote.c:10030
 adapteva#4  0x0000555555bc0e75 in remote_target::remote_hostio_send_command (this=0x555556a11040, command_bytes=13, which_packet=14, remote_errno=0x7fffffffcfd0, attachment=0x0, attachment_len=0x0) at src/gdb/remote.c:12137
 adapteva#5  0x0000555555bc1b6c in remote_target::remote_hostio_close (this=0x555556a11040, fd=8, remote_errno=0x7fffffffcfd0) at src/gdb/remote.c:12455
 adapteva#6  0x0000555555bc1bb4 in remote_target::fileio_close (During symbol reading: .debug_line address at offset 0x64f417 is 0 [in module build/gdb/gdb]
 this=0x555556a11040, fd=8, remote_errno=0x7fffffffcfd0) at src/gdb/remote.c:12462
 adapteva#7  0x0000555555c9274c in target_fileio_close (fd=3, target_errno=0x7fffffffcfd0) at src/gdb/target.c:3365
 adapteva#8  0x000055555595a19d in gdb_bfd_iovec_fileio_close (abfd=0x555556b9f8a0, stream=0x555556b11530) at src/gdb/gdb_bfd.c:439
 adapteva#9  0x0000555555e09e3f in opncls_bclose (abfd=0x555556b9f8a0) at src/bfd/opncls.c:599
 adapteva#10 0x0000555555e0a2c7 in bfd_close_all_done (abfd=0x555556b9f8a0) at src/bfd/opncls.c:847
 adapteva#11 0x0000555555e0a27a in bfd_close (abfd=0x555556b9f8a0) at src/bfd/opncls.c:814
 #12 0x000055555595a9d3 in gdb_bfd_close_or_warn (abfd=0x555556b9f8a0) at src/gdb/gdb_bfd.c:626
 #13 0x000055555595ad29 in gdb_bfd_unref (abfd=0x555556b9f8a0) at src/gdb/gdb_bfd.c:715
 #14 0x0000555555ae4730 in objfile::~objfile (this=0x555556515540, __in_chrg=<optimized out>) at src/gdb/objfiles.c:573
 #15 0x0000555555ae955a in std::_Sp_counted_ptr<objfile*, (__gnu_cxx::_Lock_policy)2>::_M_dispose (this=0x555556c20db0) at /usr/include/c++/9/bits/shared_ptr_base.h:377
 #16 0x000055555572b7c8 in std::_Sp_counted_base<(__gnu_cxx::_Lock_policy)2>::_M_release (this=0x555556c20db0) at /usr/include/c++/9/bits/shared_ptr_base.h:155
 #17 0x00005555557263c3 in std::__shared_count<(__gnu_cxx::_Lock_policy)2>::~__shared_count (this=0x555556bf0588, __in_chrg=<optimized out>) at /usr/include/c++/9/bits/shared_ptr_base.h:730
 #18 0x0000555555ae745e in std::__shared_ptr<objfile, (__gnu_cxx::_Lock_policy)2>::~__shared_ptr (this=0x555556bf0580, __in_chrg=<optimized out>) at /usr/include/c++/9/bits/shared_ptr_base.h:1169
 #19 0x0000555555ae747e in std::shared_ptr<objfile>::~shared_ptr (this=0x555556bf0580, __in_chrg=<optimized out>) at /usr/include/c++/9/bits/shared_ptr.h:103
 #20 0x0000555555b1c1dc in __gnu_cxx::new_allocator<std::_List_node<std::shared_ptr<objfile> > >::destroy<std::shared_ptr<objfile> > (this=0x5555564cdd60, __p=0x555556bf0580) at /usr/include/c++/9/ext/new_allocator.h:153
 #21 0x0000555555b1bb1d in std::allocator_traits<std::allocator<std::_List_node<std::shared_ptr<objfile> > > >::destroy<std::shared_ptr<objfile> > (__a=..., __p=0x555556bf0580) at /usr/include/c++/9/bits/alloc_traits.h:497
 #22 0x0000555555b1b73e in std::__cxx11::list<std::shared_ptr<objfile>, std::allocator<std::shared_ptr<objfile> > >::_M_erase (this=0x5555564cdd60, __position=std::shared_ptr<objfile> (expired, weak count 1) = {get() = 0x555556515540}) at /usr/include/c++/9/bits/stl_list.h:1921
 #23 0x0000555555b1afeb in std::__cxx11::list<std::shared_ptr<objfile>, std::allocator<std::shared_ptr<objfile> > >::erase (this=0x5555564cdd60, __position=std::shared_ptr<objfile> (expired, weak count 1) = {get() = 0x555556515540}) at /usr/include/c++/9/bits/list.tcc:158
 #24 0x0000555555b19576 in program_space::remove_objfile (this=0x5555564cdd20, objfile=0x555556515540) at src/gdb/progspace.c:210
 #25 0x0000555555ae4502 in objfile::unlink (this=0x555556515540) at src/gdb/objfiles.c:487
 #26 0x0000555555ae5a12 in objfile_purge_solibs () at src/gdb/objfiles.c:875
 #27 0x0000555555c09686 in no_shared_libraries (ignored=0x0, from_tty=1) at src/gdb/solib.c:1236
 #28 0x00005555559e3f5f in detach_command (args=0x0, from_tty=1) at src/gdb/infcmd.c:2769

So frame #28 already detached the remote process, and then we're
purging the shared libraries.  GDB had opened remote shared libraries
via the target: sysroot, so it tries closing them.  GDBserver is
tearing down already, so remote communication breaks down and we close
the remote target and throw TARGET_CLOSE_ERROR.

Note frame #14:

 #14 0x0000555555ae4730 in objfile::~objfile (this=0x555556515540, __in_chrg=<optimized out>) at src/gdb/objfiles.c:573

That's a dtor, thus noexcept.  That's the reason for the
std::terminate.

Stepping back a bit, why do we still have open remote files if we've
managed to detach already, and, we're debugging with "target remote"?
The reason is that commit 408f668
makes detach_command hold a reference to the target, so the remote
target won't be finally closed until frame #28 returns.  It's closing
the target that invalidates target file I/O handles.

This commit fixes the issue by not relying on target_close to
invalidate the target file I/O handles, instead invalidate them
immediately in remote_unpush_target.  So when GDB purges the solibs,
and we end up in target_fileio_close (frame adapteva#7 above), there's nothing
to do, and we don't try to talk with the remote target anymore.

The regression isn't seen when testing with
--target_board=native-gdbserver, because that does "set sysroot" to
disable the "target:" sysroot, for test run speed reasons.  So this
commit adds a testcase that explicitly tests detach with "set sysroot
target:".

gdb/ChangeLog:
yyyy-mm-dd  Pedro Alves  <pedro@palves.net>

	PR gdb/28080
	* remote.c (remote_unpush_target): Invalidate file I/O target
	handles.
	* target.c (fileio_handles_invalidate_target): Make extern.
	* target.h (fileio_handles_invalidate_target): Declare.

gdb/testsuite/ChangeLog:
yyyy-mm-dd  Pedro Alves  <pedro@palves.net>

	PR gdb/28080
	* gdb.base/detach-sysroot-target.exp: New.
	* gdb.base/detach-sysroot-target.c: New.

Reported-By: Jonah Graham <jonah@kichwacoders.com>

Change-Id: I851234910172f42a1b30e731161376c344d2727d
olajep pushed a commit to olajep/epiphany-binutils-gdb that referenced this issue Oct 16, 2022
…080)

Before PR gdb/28080 was fixed by the previous patch, GDB was crashing
like this:

 (gdb) detach
 Detaching from program: target:/any/program, process 3671843
 Detaching from process 3671843
 Ending remote debugging.
 [Inferior 1 (process 3671843) detached]
 In main
 terminate called after throwing an instance of 'gdb_exception_error'
 Aborted (core dumped)

Here's the exception above being thrown:

 (top-gdb) bt
 #0  throw_error (error=TARGET_CLOSE_ERROR, fmt=0x555556035588 "Remote connection closed") at src/gdbsupport/common-exceptions.cc:222
 adapteva#1  0x0000555555bbaa46 in remote_target::readchar (this=0x555556a11040, timeout=10000) at src/gdb/remote.c:9440
 adapteva#2  0x0000555555bbb9e5 in remote_target::getpkt_or_notif_sane_1 (this=0x555556a11040, buf=0x555556a11058, forever=0, expecting_notif=0, is_notif=0x0) at src/gdb/remote.c:9928
 adapteva#3  0x0000555555bbbda9 in remote_target::getpkt_sane (this=0x555556a11040, buf=0x555556a11058, forever=0) at src/gdb/remote.c:10030
 adapteva#4  0x0000555555bc0e75 in remote_target::remote_hostio_send_command (this=0x555556a11040, command_bytes=13, which_packet=14, remote_errno=0x7fffffffcfd0, attachment=0x0, attachment_len=0x0) at src/gdb/remote.c:12137
 adapteva#5  0x0000555555bc1b6c in remote_target::remote_hostio_close (this=0x555556a11040, fd=8, remote_errno=0x7fffffffcfd0) at src/gdb/remote.c:12455
 adapteva#6  0x0000555555bc1bb4 in remote_target::fileio_close (During symbol reading: .debug_line address at offset 0x64f417 is 0 [in module build/gdb/gdb]
 this=0x555556a11040, fd=8, remote_errno=0x7fffffffcfd0) at src/gdb/remote.c:12462
 adapteva#7  0x0000555555c9274c in target_fileio_close (fd=3, target_errno=0x7fffffffcfd0) at src/gdb/target.c:3365
 adapteva#8  0x000055555595a19d in gdb_bfd_iovec_fileio_close (abfd=0x555556b9f8a0, stream=0x555556b11530) at src/gdb/gdb_bfd.c:439
 adapteva#9  0x0000555555e09e3f in opncls_bclose (abfd=0x555556b9f8a0) at src/bfd/opncls.c:599
 adapteva#10 0x0000555555e0a2c7 in bfd_close_all_done (abfd=0x555556b9f8a0) at src/bfd/opncls.c:847
 adapteva#11 0x0000555555e0a27a in bfd_close (abfd=0x555556b9f8a0) at src/bfd/opncls.c:814
 #12 0x000055555595a9d3 in gdb_bfd_close_or_warn (abfd=0x555556b9f8a0) at src/gdb/gdb_bfd.c:626
 #13 0x000055555595ad29 in gdb_bfd_unref (abfd=0x555556b9f8a0) at src/gdb/gdb_bfd.c:715
 #14 0x0000555555ae4730 in objfile::~objfile (this=0x555556515540, __in_chrg=<optimized out>) at src/gdb/objfiles.c:573
 #15 0x0000555555ae955a in std::_Sp_counted_ptr<objfile*, (__gnu_cxx::_Lock_policy)2>::_M_dispose (this=0x555556c20db0) at /usr/include/c++/9/bits/shared_ptr_base.h:377
 #16 0x000055555572b7c8 in std::_Sp_counted_base<(__gnu_cxx::_Lock_policy)2>::_M_release (this=0x555556c20db0) at /usr/include/c++/9/bits/shared_ptr_base.h:155
 #17 0x00005555557263c3 in std::__shared_count<(__gnu_cxx::_Lock_policy)2>::~__shared_count (this=0x555556bf0588, __in_chrg=<optimized out>) at /usr/include/c++/9/bits/shared_ptr_base.h:730
 #18 0x0000555555ae745e in std::__shared_ptr<objfile, (__gnu_cxx::_Lock_policy)2>::~__shared_ptr (this=0x555556bf0580, __in_chrg=<optimized out>) at /usr/include/c++/9/bits/shared_ptr_base.h:1169
 #19 0x0000555555ae747e in std::shared_ptr<objfile>::~shared_ptr (this=0x555556bf0580, __in_chrg=<optimized out>) at /usr/include/c++/9/bits/shared_ptr.h:103
 #20 0x0000555555b1c1dc in __gnu_cxx::new_allocator<std::_List_node<std::shared_ptr<objfile> > >::destroy<std::shared_ptr<objfile> > (this=0x5555564cdd60, __p=0x555556bf0580) at /usr/include/c++/9/ext/new_allocator.h:153
 #21 0x0000555555b1bb1d in std::allocator_traits<std::allocator<std::_List_node<std::shared_ptr<objfile> > > >::destroy<std::shared_ptr<objfile> > (__a=..., __p=0x555556bf0580) at /usr/include/c++/9/bits/alloc_traits.h:497
 #22 0x0000555555b1b73e in std::__cxx11::list<std::shared_ptr<objfile>, std::allocator<std::shared_ptr<objfile> > >::_M_erase (this=0x5555564cdd60, __position=std::shared_ptr<objfile> (expired, weak count 1) = {get() = 0x555556515540}) at /usr/include/c++/9/bits/stl_list.h:1921
 #23 0x0000555555b1afeb in std::__cxx11::list<std::shared_ptr<objfile>, std::allocator<std::shared_ptr<objfile> > >::erase (this=0x5555564cdd60, __position=std::shared_ptr<objfile> (expired, weak count 1) = {get() = 0x555556515540}) at /usr/include/c++/9/bits/list.tcc:158
 #24 0x0000555555b19576 in program_space::remove_objfile (this=0x5555564cdd20, objfile=0x555556515540) at src/gdb/progspace.c:210
 #25 0x0000555555ae4502 in objfile::unlink (this=0x555556515540) at src/gdb/objfiles.c:487
 #26 0x0000555555ae5a12 in objfile_purge_solibs () at src/gdb/objfiles.c:875
 #27 0x0000555555c09686 in no_shared_libraries (ignored=0x0, from_tty=1) at src/gdb/solib.c:1236
 #28 0x00005555559e3f5f in detach_command (args=0x0, from_tty=1) at src/gdb/infcmd.c:2769

Note frame #14:

 #14 0x0000555555ae4730 in objfile::~objfile (this=0x555556515540, __in_chrg=<optimized out>) at src/gdb/objfiles.c:573

That's a dtor, thus noexcept.  That's the reason for the
std::terminate.

The previous patch fixed things such that the exception above isn't
thrown anymore.  However, it's possible that e.g., the remote
connection drops just while a user types "nosharedlibrary", or some
other reason that leads to objfile::~objfile, and then we end up the
same std::terminate problem.

Also notice that frames adapteva#9-adapteva#11 are BFD frames:

 adapteva#9  0x0000555555e09e3f in opncls_bclose (abfd=0x555556bc27e0) at src/bfd/opncls.c:599
 adapteva#10 0x0000555555e0a2c7 in bfd_close_all_done (abfd=0x555556bc27e0) at src/bfd/opncls.c:847
 adapteva#11 0x0000555555e0a27a in bfd_close (abfd=0x555556bc27e0) at src/bfd/opncls.c:814

BFD is written in C and thus throwing exceptions over such frames may
either not clean up properly, or, may abort if bfd is not compiled
with -fasynchronous-unwind-tables (x86-64 defaults that on, but not
all GCC ports do).

Thus frame adapteva#8 seems like a good place to swallow exceptions.  More so
since in this spot we already ignore target_fileio_close return
errors.  That's what this commit does.  Without the previous fix, we'd
see:

 (gdb) detach
 Detaching from program: target:/any/program, process 2197701
 Ending remote debugging.
 [Inferior 1 (process 2197701) detached]
 warning: cannot close "target:/lib64/ld-linux-x86-64.so.2": Remote connection closed

Note it prints a warning, which would still be a regression compared
to GDB 10, if it weren't for the previous fix.

gdb/ChangeLog:
yyyy-mm-dd  Pedro Alves  <pedro@palves.net>

	PR gdb/28080
	* gdb_bfd.c (gdb_bfd_close_warning): New.
	(gdb_bfd_iovec_fileio_close): Wrap target_fileio_close in
	try/catch and print warning on exception.
	(gdb_bfd_close_or_warn): Use gdb_bfd_close_warning.

Change-Id: Ic7a26ddba0a4444e3377b0e7c1c89934a84545d7
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