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Live migration fails with "qemu-kvm: htab_load() bad index in htab stream (htab_shift=0)" #6

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balamuruhans opened this issue Sep 28, 2017 · 3 comments

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@balamuruhans
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balamuruhans commented Sep 28, 2017

Description:
Basic Live migration is broken in HostOS 3.0 with "qemu-kvm: htab_load() bad index in htab stream (htab_shift=0)".

Used P9 Boston DD2.0 Host and Fedora 26 Guest:

# cat /proc/cpuinfo | grep revision
revision	: 2.0 (pvr 004e 1200)

Steps to recreate:

  1. Have a healthy guest with qcow2 image with shared storage in NFS
  2. Mount the image location in source and in destination.
  3. Enabled ports 49152:49216 in iptables in destination host,
    # iptables -I INPUT -p tcp -m tcp --dport 49152:49216 -j ACCEPT
  4. Permit selinux to allow libvirt for using NFS in source and destination,
    # setsebool virt_use_nfs 1
  5. start the guest in source and perform postcopy migration
    # virsh start avocado-vt-vm1-migration
# virsh list
 Id    Name                           State
----------------------------------------------------
 49    avocado-vt-vm1-migration       running

  1. Perform migration and issue is observed,
# virsh migrate avocado-vt-vm1-migration qemu+ssh://9.40.193.221/system --live --verbose
root@9.40.193.221's password: 
error: internal error: qemu unexpectedly closed the monitor: 2017-09-28T05:20:14.858662Z qemu-kvm: -chardev pty,id=charserial0: char device redirected to /dev/pts/1 (label charserial0)
2017-09-28T05:20:15.182815Z qemu-kvm: htab_load() bad index 2113929216 (23554+0 entries) in htab stream (htab_shift=0)
2017-09-28T05:20:15.182851Z qemu-kvm: error while loading state for instance 0x0 of device 'spapr/htab'
2017-09-28T05:20:15.184847Z qemu-kvm: load of migration failed: Invalid argument

Test Environment: (In source and destination host)
Qemu:

# rpm -qa | grep qemu
qemu-img-ev-2.9.0-16.el7_4.5.1.ppc64le
ipxe-roms-qemu-20170123-1.git4e85b27.el7_4.1.noarch
qemu-kvm-ev-2.9.0-16.el7_4.5.1.ppc64le
libvirt-daemon-driver-qemu-3.2.0-14.el7_4.3.ppc64le
qemu-kvm-common-ev-2.9.0-16.el7_4.5.1.ppc64le

Libvirt:

# rpm -qa | grep libvirt
libvirt-daemon-driver-storage-core-3.2.0-14.el7_4.3.ppc64le
libvirt-daemon-config-nwfilter-3.2.0-14.el7_4.3.ppc64le
libvirt-daemon-driver-storage-iscsi-3.2.0-14.el7_4.3.ppc64le
libvirt-daemon-driver-storage-logical-3.2.0-14.el7_4.3.ppc64le
libvirt-daemon-driver-interface-3.2.0-14.el7_4.3.ppc64le
libvirt-daemon-3.2.0-14.el7_4.3.ppc64le
libvirt-daemon-driver-network-3.2.0-14.el7_4.3.ppc64le
libvirt-client-3.2.0-14.el7_4.3.ppc64le
libvirt-daemon-config-network-3.2.0-14.el7_4.3.ppc64le
libvirt-daemon-driver-lxc-3.2.0-14.el7_4.3.ppc64le
libvirt-daemon-driver-storage-scsi-3.2.0-14.el7_4.3.ppc64le
libvirt-daemon-driver-storage-mpath-3.2.0-14.el7_4.3.ppc64le
libvirt-daemon-driver-storage-3.2.0-14.el7_4.3.ppc64le
libvirt-daemon-driver-secret-3.2.0-14.el7_4.3.ppc64le
libvirt-python-3.2.0-3.el7.ppc64le
libvirt-devel-3.2.0-14.el7_4.3.ppc64le
libvirt-libs-3.2.0-14.el7_4.3.ppc64le
libvirt-daemon-driver-nwfilter-3.2.0-14.el7_4.3.ppc64le
libvirt-daemon-driver-qemu-3.2.0-14.el7_4.3.ppc64le
libvirt-daemon-driver-storage-disk-3.2.0-14.el7_4.3.ppc64le
libvirt-daemon-driver-nodedev-3.2.0-14.el7_4.3.ppc64le
libvirt-3.2.0-14.el7_4.3.ppc64le

Host kernel:

# uname -a
Linux ltc-boston120.aus.stglabs.ibm.com 4.13.0-4.rel.git49564cb.el7.centos.ppc64le #1 SMP Fri Sep 22 22:49:59 -03 2017 ppc64le ppc64le ppc64le GNU/Linux

Guest (Fedora 26) Kernel:

# uname -a
Linux localhost.localdomain 4.12.13-300.fc26.ppc64le #1 SMP Thu Sep 14 15:47:43 UTC 2017 ppc64le ppc64le ppc64le GNU/Linux

cde:info Mirrored with LTC bug #159384 </cde:info>

@balamuruhans
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Attachment: libvirtd debug logs of source and destination:
libvirtd_source.tar.gz
libvirtd_destination.tar.gz

@bssrikanth
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we will try migration with qemu 2.10 will get back here..

@bssrikanth
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We had got in wrong qemu version. With QEMU 2.10 we are not hitting any issues with migration. Closing this bug.

aik pushed a commit that referenced this issue Jan 31, 2018
The passed-through device might be an express device. In this case the
old code allocated a too small emulated config space in
pci_config_alloc() since pci_config_size() returned the size for a
non-express device. This leads to an out-of-bound write in
xen_pt_config_reg_init(), which sometimes results in crashes. So set
is_express as already done for KVM in vfio-pci.

Shortened ASan report:

==17512==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x611000041648 at pc 0x55e0fdac51ff bp 0x7ffe4af07410 sp 0x7ffe4af07408
WRITE of size 2 at 0x611000041648 thread T0
    #0 0x55e0fdac51fe in memcpy /usr/include/x86_64-linux-gnu/bits/string3.h:53
    #1 0x55e0fdac51fe in stw_he_p include/qemu/bswap.h:330
    #2 0x55e0fdac51fe in stw_le_p include/qemu/bswap.h:379
    #3 0x55e0fdac51fe in pci_set_word include/hw/pci/pci.h:490
    #4 0x55e0fdac51fe in xen_pt_config_reg_init hw/xen/xen_pt_config_init.c:1991
    #5 0x55e0fdac51fe in xen_pt_config_init hw/xen/xen_pt_config_init.c:2067
    #6 0x55e0fdabcf4d in xen_pt_realize hw/xen/xen_pt.c:830
    #7 0x55e0fdf59666 in pci_qdev_realize hw/pci/pci.c:2034
    #8 0x55e0fdda7d3d in device_set_realized hw/core/qdev.c:914
[...]

0x611000041648 is located 8 bytes to the right of 256-byte region [0x611000041540,0x611000041640)
allocated by thread T0 here:
    #0 0x7ff596a94bb8 in __interceptor_calloc (/usr/lib/x86_64-linux-gnu/libasan.so.4+0xd9bb8)
    #1 0x7ff57da66580 in g_malloc0 (/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x50580)
    #2 0x55e0fdda7d3d in device_set_realized hw/core/qdev.c:914
[...]

Signed-off-by: Simon Gaiser <hw42@ipsumj.de>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>
Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>
aik pushed a commit that referenced this issue Jan 31, 2018
bdrv_unref() requires the AioContext lock because bdrv_flush() uses
BDRV_POLL_WHILE(), which assumes the AioContext is currently held.  If
BDRV_POLL_WHILE() runs without AioContext held the
pthread_mutex_unlock() call in aio_context_release() fails.

This patch moves bdrv_unref() into the AioContext locked region to solve
the following pthread_mutex_unlock() failure:

  #0  0x00007f566181969b in raise () at /lib64/libc.so.6
  #1  0x00007f566181b3b1 in abort () at /lib64/libc.so.6
  #2  0x00005592cd590458 in error_exit (err=<optimized out>, msg=msg@entry=0x5592cdaf6d60 <__func__.23977> "qemu_mutex_unlock") at util/qemu-thread-posix.c:36
  #3  0x00005592cd96e738 in qemu_mutex_unlock (mutex=mutex@entry=0x5592ce9505e0) at util/qemu-thread-posix.c:96
  #4  0x00005592cd969b69 in aio_context_release (ctx=ctx@entry=0x5592ce950580) at util/async.c:507
  #5  0x00005592cd8ead78 in bdrv_flush (bs=bs@entry=0x5592cfa87210) at block/io.c:2478
  #6  0x00005592cd89df30 in bdrv_close (bs=0x5592cfa87210) at block.c:3207
  #7  0x00005592cd89df30 in bdrv_delete (bs=0x5592cfa87210) at block.c:3395
  #8  0x00005592cd89df30 in bdrv_unref (bs=0x5592cfa87210) at block.c:4418
  #9  0x00005592cd6b7f86 in qmp_transaction (dev_list=<optimized out>, has_props=<optimized out>, props=<optimized out>, errp=errp@entry=0x7ffe4a1fc9d8) at blockdev.c:2308

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 20171206144550.22295-2-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
aik pushed a commit that referenced this issue Jan 31, 2018
There is a small chance that iothread_stop() hangs as follows:

  Thread 3 (Thread 0x7f63eba5f700 (LWP 16105)):
  #0  0x00007f64012c09b6 in ppoll () at /lib64/libc.so.6
  #1  0x000055959992eac9 in ppoll (__ss=0x0, __timeout=0x0, __nfds=<optimized out>, __fds=<optimized out>) at /usr/include/bits/poll2.h:77
  #2  0x000055959992eac9 in qemu_poll_ns (fds=<optimized out>, nfds=<optimized out>, timeout=<optimized out>) at util/qemu-timer.c:322
  #3  0x0000559599930711 in aio_poll (ctx=0x55959bdb83c0, blocking=blocking@entry=true) at util/aio-posix.c:629
  #4  0x00005595996806fe in iothread_run (opaque=0x55959bd78400) at iothread.c:59
  #5  0x00007f640159f609 in start_thread () at /lib64/libpthread.so.0
  #6  0x00007f64012cce6f in clone () at /lib64/libc.so.6

  Thread 1 (Thread 0x7f640b45b280 (LWP 16103)):
  #0  0x00007f64015a0b6d in pthread_join () at /lib64/libpthread.so.0
  #1  0x00005595999332ef in qemu_thread_join (thread=<optimized out>) at util/qemu-thread-posix.c:547
  #2  0x00005595996808ae in iothread_stop (iothread=<optimized out>) at iothread.c:91
  #3  0x000055959968094d in iothread_stop_iter (object=<optimized out>, opaque=<optimized out>) at iothread.c:102
  #4  0x0000559599857d97 in do_object_child_foreach (obj=obj@entry=0x55959bdb8100, fn=fn@entry=0x559599680930 <iothread_stop_iter>, opaque=opaque@entry=0x0, recurse=recurse@entry=false) at qom/object.c:852
  #5  0x0000559599859477 in object_child_foreach (obj=obj@entry=0x55959bdb8100, fn=fn@entry=0x559599680930 <iothread_stop_iter>, opaque=opaque@entry=0x0) at qom/object.c:867
  #6  0x0000559599680a6e in iothread_stop_all () at iothread.c:341
  #7  0x000055959955b1d5 in main (argc=<optimized out>, argv=<optimized out>, envp=<optimized out>) at vl.c:4913

The relevant code from iothread_run() is:

  while (!atomic_read(&iothread->stopping)) {
      aio_poll(iothread->ctx, true);

and iothread_stop():

  iothread->stopping = true;
  aio_notify(iothread->ctx);
  ...
  qemu_thread_join(&iothread->thread);

The following scenario can occur:

1. IOThread:
  while (!atomic_read(&iothread->stopping)) -> stopping=false

2. Main loop:
  iothread->stopping = true;
  aio_notify(iothread->ctx);

3. IOThread:
  aio_poll(iothread->ctx, true); -> hang

The bug is explained by the AioContext->notify_me doc comments:

  "If this field is 0, everything (file descriptors, bottom halves,
  timers) will be re-evaluated before the next blocking poll(), thus the
  event_notifier_set call can be skipped."

The problem is that "everything" does not include checking
iothread->stopping.  This means iothread_run() will block in aio_poll()
if aio_notify() was called just before aio_poll().

This patch fixes the hang by replacing aio_notify() with
aio_bh_schedule_oneshot().  This makes aio_poll() or g_main_loop_run()
to return.

Implementing this properly required a new bool running flag.  The new
flag prevents races that are tricky if we try to use iothread->stopping.
Now iothread->stopping is purely for iothread_stop() and
iothread->running is purely for the iothread_run() thread.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 20171207201320.19284-6-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
aik pushed a commit that referenced this issue Jan 31, 2018
If we create a thread with QEMU_THREAD_DETACHED mode, QEMU may get a segfault with low probability.

The backtrace is:
   #0  0x00007f46c60291d7 in __GI_raise (sig=sig@entry=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:56
   #1  0x00007f46c602a8c8 in __GI_abort () at abort.c:90
   #2  0x00000000008543c9 in PAT_abort ()
   #3  0x000000000085140d in patchIllInsHandler ()
   #4  <signal handler called>
   #5  pthread_detach (th=139933037614848) at pthread_detach.c:50
   #6  0x0000000000829759 in qemu_thread_create (thread=thread@entry=0x7ffdaa8205e0, name=name@entry=0x94d94a "io-task-worker", start_routine=start_routine@entry=0x7eb9a0 <qio_task_thread_worker>,
       arg=arg@entry=0x3f5cf70, mode=mode@entry=1) at util/qemu_thread_posix.c:512
   #7  0x00000000007ebc96 in qio_task_run_in_thread (task=0x31db2c0, worker=worker@entry=0x7e7e40 <qio_channel_socket_connect_worker>, opaque=0xcd23380, destroy=0x7f1180 <qapi_free_SocketAddress>)
       at io/task.c:141
   #8  0x00000000007e7f33 in qio_channel_socket_connect_async (ioc=ioc@entry=0x626c0b0, addr=<optimized out>, callback=callback@entry=0x55e080 <qemu_chr_socket_connected>, opaque=opaque@entry=0x42862c0,
       destroy=destroy@entry=0x0) at io/channel_socket.c:194
   #9  0x000000000055bdd1 in socket_reconnect_timeout (opaque=0x42862c0) at qemu_char.c:4744
   #10 0x00007f46c72483b3 in g_timeout_dispatch () from /usr/lib64/libglib-2.0.so.0
   #11 0x00007f46c724799a in g_main_context_dispatch () from /usr/lib64/libglib-2.0.so.0
   #12 0x000000000076c646 in glib_pollfds_poll () at main_loop.c:228
   #13 0x000000000076c6eb in os_host_main_loop_wait (timeout=348000000) at main_loop.c:273
   #14 0x000000000076c815 in main_loop_wait (nonblocking=nonblocking@entry=0) at main_loop.c:521
   #15 0x000000000056a511 in main_loop () at vl.c:2076
   #16 0x0000000000420705 in main (argc=<optimized out>, argv=<optimized out>, envp=<optimized out>) at vl.c:4940

The cause of this problem is a glibc bug; for more information, see
https://sourceware.org/bugzilla/show_bug.cgi?id=19951.
The solution for this bug is to use pthread_attr_setdetachstate.

There is a similar issue with pthread_setname_np, which is moved
from creating thread to created thread.

Signed-off-by: linzhecheng <linzhecheng@huawei.com>
Message-Id: <20171128044656.10592-1-linzhecheng@huawei.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
[Simplify the code by removing qemu_thread_set_name, and free the arguments
 before invoking the start routine. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
aik pushed a commit that referenced this issue Jan 31, 2018
/public/qobject_is_equal_conversion: OK

=================================================================
==14396==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 56 byte(s) in 1 object(s) allocated from:
    #0 0x7f07682c5850 in malloc (/lib64/libasan.so.4+0xde850)
    #1 0x7f0767d12f0c in g_malloc ../glib/gmem.c:94
    #2 0x7f0767d131cf in g_malloc_n ../glib/gmem.c:331
    #3 0x562bd767371f in do_test_equality /home/elmarco/src/qq/tests/check-qobject.c:49
    #4 0x562bd7674a35 in qobject_is_equal_dict_test /home/elmarco/src/qq/tests/check-qobject.c:267
    #5 0x7f0767d37b04 in test_case_run ../glib/gtestutils.c:2237
    #6 0x7f0767d37ec4 in g_test_run_suite_internal ../glib/gtestutils.c:2321
    #7 0x7f0767d37f6d in g_test_run_suite_internal ../glib/gtestutils.c:2333
    #8 0x7f0767d38184 in g_test_run_suite ../glib/gtestutils.c:2408
    #9 0x7f0767d36e0d in g_test_run ../glib/gtestutils.c:1674
    #10 0x562bd7674e75 in main /home/elmarco/src/qq/tests/check-qobject.c:327
    #11 0x7f0766009039 in __libc_start_main (/lib64/libc.so.6+0x21039)

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20180104160523.22995-9-marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
aik pushed a commit that referenced this issue Jan 31, 2018
Fixes leaks such as:

Direct leak of 2 byte(s) in 1 object(s) allocated from:
    #0 0x7eff58beb850 in malloc (/lib64/libasan.so.4+0xde850)
    #1 0x7eff57942f0c in g_malloc ../glib/gmem.c:94
    #2 0x7eff579431cf in g_malloc_n ../glib/gmem.c:331
    #3 0x7eff5795f6eb in g_strdup ../glib/gstrfuncs.c:363
    #4 0x55db720f1d46 in readline_hist_add /home/elmarco/src/qq/util/readline.c:258
    #5 0x55db720f2d34 in readline_handle_byte /home/elmarco/src/qq/util/readline.c:387
    #6 0x55db71539d00 in monitor_read /home/elmarco/src/qq/monitor.c:3896
    #7 0x55db71f9be35 in qemu_chr_be_write_impl /home/elmarco/src/qq/chardev/char.c:167
    #8 0x55db71f9bed3 in qemu_chr_be_write /home/elmarco/src/qq/chardev/char.c:179
    #9 0x55db71fa013c in fd_chr_read /home/elmarco/src/qq/chardev/char-fd.c:66
    #10 0x55db71fe18a8 in qio_channel_fd_source_dispatch /home/elmarco/src/qq/io/channel-watch.c:84
    #11 0x7eff5793a90b in g_main_dispatch ../glib/gmain.c:3182
    #12 0x7eff5793b7ac in g_main_context_dispatch ../glib/gmain.c:3847
    #13 0x55db720af3bd in glib_pollfds_poll /home/elmarco/src/qq/util/main-loop.c:214
    #14 0x55db720af505 in os_host_main_loop_wait /home/elmarco/src/qq/util/main-loop.c:261
    #15 0x55db720af6d6 in main_loop_wait /home/elmarco/src/qq/util/main-loop.c:515
    #16 0x55db7184e0de in main_loop /home/elmarco/src/qq/vl.c:1995
    #17 0x55db7185e956 in main /home/elmarco/src/qq/vl.c:4914
    #18 0x7eff4ea17039 in __libc_start_main (/lib64/libc.so.6+0x21039)

(while at it, use g_new0(ReadLineState), it's a bit easier to read)

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20180104160523.22995-11-marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
aik pushed a commit that referenced this issue Jan 31, 2018
ASAN complains about:

==8856==ERROR: AddressSanitizer: stack-buffer-overflow on address 0x7ffd8a1fe168 at pc 0x561136cb4451 bp 0x7ffd8a1fe130 sp 0x7ffd8a1fd8e0
READ of size 16 at 0x7ffd8a1fe168 thread T0
    #0 0x561136cb4450 in __asan_memcpy (/home/elmarco/src/qq/build/tests/test-crypto-ivgen+0x110450)
    #1 0x561136d2a6a7 in qcrypto_ivgen_essiv_calculate /home/elmarco/src/qq/crypto/ivgen-essiv.c:83:5
    #2 0x561136d29af8 in qcrypto_ivgen_calculate /home/elmarco/src/qq/crypto/ivgen.c:72:12
    #3 0x561136d07c8e in test_ivgen /home/elmarco/src/qq/tests/test-crypto-ivgen.c:148:5
    #4 0x7f77772c3b04 in test_case_run /home/elmarco/src/gnome/glib/builddir/../glib/gtestutils.c:2237
    #5 0x7f77772c3ec4 in g_test_run_suite_internal /home/elmarco/src/gnome/glib/builddir/../glib/gtestutils.c:2321
    #6 0x7f77772c3f6d in g_test_run_suite_internal /home/elmarco/src/gnome/glib/builddir/../glib/gtestutils.c:2333
    #7 0x7f77772c3f6d in g_test_run_suite_internal /home/elmarco/src/gnome/glib/builddir/../glib/gtestutils.c:2333
    #8 0x7f77772c3f6d in g_test_run_suite_internal /home/elmarco/src/gnome/glib/builddir/../glib/gtestutils.c:2333
    #9 0x7f77772c4184 in g_test_run_suite /home/elmarco/src/gnome/glib/builddir/../glib/gtestutils.c:2408
    #10 0x7f77772c2e0d in g_test_run /home/elmarco/src/gnome/glib/builddir/../glib/gtestutils.c:1674
    #11 0x561136d0799b in main /home/elmarco/src/qq/tests/test-crypto-ivgen.c:173:12
    #12 0x7f77756e6039 in __libc_start_main (/lib64/libc.so.6+0x21039)
    #13 0x561136c13d89 in _start (/home/elmarco/src/qq/build/tests/test-crypto-ivgen+0x6fd89)

Address 0x7ffd8a1fe168 is located in stack of thread T0 at offset 40 in frame
    #0 0x561136d2a40f in qcrypto_ivgen_essiv_calculate /home/elmarco/src/qq/crypto/ivgen-essiv.c:76

  This frame has 1 object(s):
    [32, 40) 'sector.addr' <== Memory access at offset 40 overflows this variable
HINT: this may be a false positive if your program uses some custom stack unwind mechanism or swapcontext
      (longjmp and C++ exceptions *are* supported)
SUMMARY: AddressSanitizer: stack-buffer-overflow (/home/elmarco/src/qq/build/tests/test-crypto-ivgen+0x110450) in __asan_memcpy
Shadow bytes around the buggy address:
  0x100031437bd0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x100031437be0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x100031437bf0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x100031437c00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x100031437c10: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x100031437c20: 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00[f3]f3 f3
  0x100031437c30: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x100031437c40: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x100031437c50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x100031437c60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x100031437c70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
Shadow byte legend (one shadow byte represents 8 application bytes):
  Addressable:           00
  Partially addressable: 01 02 03 04 05 06 07
  Heap left redzone:       fa
  Freed heap region:       fd
  Stack left redzone:      f1
  Stack mid redzone:       f2
  Stack right redzone:     f3
  Stack after return:      f5
  Stack use after scope:   f8
  Global redzone:          f9
  Global init order:       f6
  Poisoned by user:        f7
  Container overflow:      fc
  Array cookie:            ac
  Intra object redzone:    bb
  ASan internal:           fe
  Left alloca redzone:     ca
  Right alloca redzone:    cb

It looks like the rest of the code copes with ndata being larger than
sizeof(sector), so limit the memcpy() range.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Message-Id: <20180104160523.22995-13-marcandre.lureau@redhat.com>
Tested-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
aik pushed a commit that referenced this issue Jan 31, 2018
Direct leak of 160 byte(s) in 4 object(s) allocated from:
    #0 0x55ed7678cda8 in calloc (/home/elmarco/src/qq/build/x86_64-softmmu/qemu-system-x86_64+0x797da8)
    #1 0x7f3f5e725f75 in g_malloc0 /home/elmarco/src/gnome/glib/builddir/../glib/gmem.c:124
    #2 0x55ed778aa3a7 in query_option_descs /home/elmarco/src/qq/util/qemu-config.c:60:16
    #3 0x55ed778aa307 in get_drive_infolist /home/elmarco/src/qq/util/qemu-config.c:140:19
    #4 0x55ed778a9f40 in qmp_query_command_line_options /home/elmarco/src/qq/util/qemu-config.c:254:36
    #5 0x55ed76d4868c in qmp_marshal_query_command_line_options /home/elmarco/src/qq/build/qmp-marshal.c:3078:14
    #6 0x55ed77855dd5 in do_qmp_dispatch /home/elmarco/src/qq/qapi/qmp-dispatch.c:104:5
    #7 0x55ed778558cc in qmp_dispatch /home/elmarco/src/qq/qapi/qmp-dispatch.c:131:11
    #8 0x55ed768b592f in handle_qmp_command /home/elmarco/src/qq/monitor.c:3840:11
    #9 0x55ed7786ccfe in json_message_process_token /home/elmarco/src/qq/qobject/json-streamer.c:105:5
    #10 0x55ed778fe37c in json_lexer_feed_char /home/elmarco/src/qq/qobject/json-lexer.c:323:13
    #11 0x55ed778fdde6 in json_lexer_feed /home/elmarco/src/qq/qobject/json-lexer.c:373:15
    #12 0x55ed7786cd83 in json_message_parser_feed /home/elmarco/src/qq/qobject/json-streamer.c:124:12
    #13 0x55ed768b559e in monitor_qmp_read /home/elmarco/src/qq/monitor.c:3882:5
    #14 0x55ed77714f29 in qemu_chr_be_write_impl /home/elmarco/src/qq/chardev/char.c:167:9
    #15 0x55ed77714fde in qemu_chr_be_write /home/elmarco/src/qq/chardev/char.c:179:9
    #16 0x55ed7772ffad in tcp_chr_read /home/elmarco/src/qq/chardev/char-socket.c:440:13
    #17 0x55ed7777113b in qio_channel_fd_source_dispatch /home/elmarco/src/qq/io/channel-watch.c:84:12
    #18 0x7f3f5e71d90b in g_main_dispatch /home/elmarco/src/gnome/glib/builddir/../glib/gmain.c:3182
    #19 0x7f3f5e71e7ac in g_main_context_dispatch /home/elmarco/src/gnome/glib/builddir/../glib/gmain.c:3847
    #20 0x55ed77886ffc in glib_pollfds_poll /home/elmarco/src/qq/util/main-loop.c:214:9
    #21 0x55ed778865fd in os_host_main_loop_wait /home/elmarco/src/qq/util/main-loop.c:261:5
    #22 0x55ed77886222 in main_loop_wait /home/elmarco/src/qq/util/main-loop.c:515:11
    #23 0x55ed76d2a4df in main_loop /home/elmarco/src/qq/vl.c:1995:9
    #24 0x55ed76d1cb4a in main /home/elmarco/src/qq/vl.c:4914:5
    #25 0x7f3f555f6039 in __libc_start_main (/lib64/libc.so.6+0x21039)

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180104160523.22995-14-marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
aik pushed a commit that referenced this issue Jan 31, 2018
The coroutine is not finished by the time the test ends, resulting in
ASAN warning:

==7005==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 312 byte(s) in 1 object(s) allocated from:
    #0 0x7fd35290fa38 in __interceptor_calloc (/lib64/libasan.so.4+0xdea38)
    #1 0x7fd3506c5f75 in g_malloc0 ../glib/gmem.c:124
    #2 0x55994af03e47 in qemu_coroutine_new /home/elmarco/src/qemu/util/coroutine-ucontext.c:144
    #3 0x55994aefed99 in qemu_coroutine_create /home/elmarco/src/qemu/util/qemu-coroutine.c:76
    #4 0x55994ac1eb50 in verify_entered_step_1 /home/elmarco/src/qemu/tests/test-coroutine.c:80
    #5 0x55994af03c75 in coroutine_trampoline /home/elmarco/src/qemu/util/coroutine-ucontext.c:119
    #6 0x7fd34ec02bef  (/lib64/libc.so.6+0x50bef)

Do not yield() to let the coroutine terminate.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20180104160523.22995-17-marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
aik pushed a commit that referenced this issue Jan 31, 2018
Spotted thanks to ASAN:

==25226==ERROR: AddressSanitizer: global-buffer-overflow on address 0x556715a1f120 at pc 0x556714b6f6b1 bp 0x7ffcdfac1360 sp 0x7ffcdfac1350
READ of size 1 at 0x556715a1f120 thread T0
    #0 0x556714b6f6b0 in init_disasm /home/elmarco/src/qemu/disas/s390.c:219
    #1 0x556714b6fa6a in print_insn_s390 /home/elmarco/src/qemu/disas/s390.c:294
    #2 0x55671484d031 in monitor_disas /home/elmarco/src/qemu/disas.c:635
    #3 0x556714862ec0 in memory_dump /home/elmarco/src/qemu/monitor.c:1324
    #4 0x55671486342a in hmp_memory_dump /home/elmarco/src/qemu/monitor.c:1418
    #5 0x5567148670be in handle_hmp_command /home/elmarco/src/qemu/monitor.c:3109
    #6 0x5567148674ed in qmp_human_monitor_command /home/elmarco/src/qemu/monitor.c:613
    #7 0x556714b00918 in qmp_marshal_human_monitor_command /home/elmarco/src/qemu/build/qmp-marshal.c:1704
    #8 0x556715138a3e in do_qmp_dispatch /home/elmarco/src/qemu/qapi/qmp-dispatch.c:104
    #9 0x556715138f83 in qmp_dispatch /home/elmarco/src/qemu/qapi/qmp-dispatch.c:131
    #10 0x55671485cf88 in handle_qmp_command /home/elmarco/src/qemu/monitor.c:3839
    #11 0x55671514e80b in json_message_process_token /home/elmarco/src/qemu/qobject/json-streamer.c:105
    #12 0x5567151bf2dc in json_lexer_feed_char /home/elmarco/src/qemu/qobject/json-lexer.c:323
    #13 0x5567151bf827 in json_lexer_feed /home/elmarco/src/qemu/qobject/json-lexer.c:373
    #14 0x55671514ee62 in json_message_parser_feed /home/elmarco/src/qemu/qobject/json-streamer.c:124
    #15 0x556714854b1f in monitor_qmp_read /home/elmarco/src/qemu/monitor.c:3881
    #16 0x556715045440 in qemu_chr_be_write_impl /home/elmarco/src/qemu/chardev/char.c:172
    #17 0x556715047184 in qemu_chr_be_write /home/elmarco/src/qemu/chardev/char.c:184
    #18 0x55671505a8e6 in tcp_chr_read /home/elmarco/src/qemu/chardev/char-socket.c:440
    #19 0x5567150943c3 in qio_channel_fd_source_dispatch /home/elmarco/src/qemu/io/channel-watch.c:84
    #20 0x7fb90292b90b in g_main_dispatch ../glib/gmain.c:3182
    #21 0x7fb90292c7ac in g_main_context_dispatch ../glib/gmain.c:3847
    #22 0x556715162eca in glib_pollfds_poll /home/elmarco/src/qemu/util/main-loop.c:214
    #23 0x556715163001 in os_host_main_loop_wait /home/elmarco/src/qemu/util/main-loop.c:261
    #24 0x5567151631fa in main_loop_wait /home/elmarco/src/qemu/util/main-loop.c:515
    #25 0x556714ad6d3b in main_loop /home/elmarco/src/qemu/vl.c:1950
    #26 0x556714ade329 in main /home/elmarco/src/qemu/vl.c:4865
    #27 0x7fb8fe5c9009 in __libc_start_main (/lib64/libc.so.6+0x21009)
    #28 0x5567147af4d9 in _start (/home/elmarco/src/qemu/build/s390x-softmmu/qemu-system-s390x+0xf674d9)

0x556715a1f120 is located 32 bytes to the left of global variable 'char_hci_type_info' defined in '/home/elmarco/src/qemu/hw/bt/hci-csr.c:493:23' (0x556715a1f140) of size 104
0x556715a1f120 is located 8 bytes to the right of global variable 's390_opcodes' defined in '/home/elmarco/src/qemu/disas/s390.c:860:33' (0x556715a15280) of size 40600

This fix is based on Andreas Arnez <arnez@linux.vnet.ibm.com> upstream
commit:
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=commitdiff;h=9ace48f3d7d80ce09c5df60cccb433470410b11b

2014-08-19  Andreas Arnez  <arnez@linux.vnet.ibm.com>

       * s390-dis.c (init_disasm): Simplify initialization of
       opc_index[].  This also fixes an access after the last element
       of s390_opcodes[].

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20180104160523.22995-19-marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
aik pushed a commit that referenced this issue Mar 29, 2018
Spotted by ASAN:
QTEST_QEMU_BINARY=aarch64-softmmu/qemu-system-aarch64 tests/boot-serial-test

Direct leak of 48 byte(s) in 1 object(s) allocated from:
    #0 0x7ff8a9b0ca38 in __interceptor_calloc (/lib64/libasan.so.4+0xdea38)
    #1 0x7ff8a8ea7f75 in g_malloc0 ../glib/gmem.c:124
    #2 0x55fef3d99129 in error_setv /home/elmarco/src/qemu/util/error.c:59
    #3 0x55fef3d99738 in error_setg_internal /home/elmarco/src/qemu/util/error.c:95
    #4 0x55fef323acb2 in load_elf_hdr /home/elmarco/src/qemu/hw/core/loader.c:393
    #5 0x55fef2d15776 in arm_load_elf /home/elmarco/src/qemu/hw/arm/boot.c:830
    #6 0x55fef2d16d39 in arm_load_kernel_notify /home/elmarco/src/qemu/hw/arm/boot.c:1022
    #7 0x55fef3dc634d in notifier_list_notify /home/elmarco/src/qemu/util/notify.c:40
    #8 0x55fef2fc3182 in qemu_run_machine_init_done_notifiers /home/elmarco/src/qemu/vl.c:2716
    #9 0x55fef2fcbbd1 in main /home/elmarco/src/qemu/vl.c:4679
    #10 0x7ff89dfed009 in __libc_start_main (/lib64/libc.so.6+0x21009)

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
aik pushed a commit that referenced this issue Mar 29, 2018
Spotted by ASAN:

elmarco@boraha:~/src/qemu/build (master *%)$ QTEST_QEMU_BINARY=aarch64-softmmu/qemu-system-aarch64 tests/boot-serial-test
/aarch64/boot-serial/virt: ** (process:19740): DEBUG: 18:39:30.275: foo /tmp/qtest-boot-serial-cXaS94D
=================================================================
==19740==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x603000069648 at pc 0x7f1d2201cc54 bp 0x7fff331f6a40 sp 0x7fff331f61e8
READ of size 4 at 0x603000069648 thread T0
    #0 0x7f1d2201cc53  (/lib64/libasan.so.4+0xafc53)
    #1 0x55bc86685ee3 in load_aarch64_image /home/elmarco/src/qemu/hw/arm/boot.c:894
    #2 0x55bc86687217 in arm_load_kernel_notify /home/elmarco/src/qemu/hw/arm/boot.c:1047
    #3 0x55bc877363b5 in notifier_list_notify /home/elmarco/src/qemu/util/notify.c:40
    #4 0x55bc869331ea in qemu_run_machine_init_done_notifiers /home/elmarco/src/qemu/vl.c:2716
    #5 0x55bc8693bc39 in main /home/elmarco/src/qemu/vl.c:4679
    #6 0x7f1d1652c009 in __libc_start_main (/lib64/libc.so.6+0x21009)
    #7 0x55bc86255cc9 in _start (/home/elmarco/src/qemu/build/aarch64-softmmu/qemu-system-aarch64+0x1ae5cc9)

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
aik pushed a commit that referenced this issue Mar 29, 2018
Spotted thanks to ASAN:
QTEST_QEMU_BINARY=x86_64-softmmu/qemu-system-x86_64 tests/migration-test -p /x86_64/migration/bad_dest

==30302==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 48 byte(s) in 1 object(s) allocated from:
    #0 0x7f60efba1a38 in __interceptor_calloc (/lib64/libasan.so.4+0xdea38)
    #1 0x7f60eef3cf75 in g_malloc0 ../glib/gmem.c:124
    #2 0x55ca9094702c in error_copy /home/elmarco/src/qemu/util/error.c:203
    #3 0x55ca9037a30f in migrate_set_error /home/elmarco/src/qemu/migration/migration.c:1139
    #4 0x55ca9037a462 in migrate_fd_error /home/elmarco/src/qemu/migration/migration.c:1150
    #5 0x55ca9038162b in migrate_fd_connect /home/elmarco/src/qemu/migration/migration.c:2411
    #6 0x55ca90386e41 in migration_channel_connect /home/elmarco/src/qemu/migration/channel.c:81
    #7 0x55ca9038335e in socket_outgoing_migration /home/elmarco/src/qemu/migration/socket.c:85
    #8 0x55ca9083dd3a in qio_task_complete /home/elmarco/src/qemu/io/task.c:142
    #9 0x55ca9083d6cc in gio_task_thread_result /home/elmarco/src/qemu/io/task.c:88
    #10 0x7f60eef37317 in g_idle_dispatch ../glib/gmain.c:5552
    #11 0x7f60eef3490b in g_main_dispatch ../glib/gmain.c:3182
    #12 0x7f60eef357ac in g_main_context_dispatch ../glib/gmain.c:3847
    #13 0x55ca90927231 in glib_pollfds_poll /home/elmarco/src/qemu/util/main-loop.c:214
    #14 0x55ca90927420 in os_host_main_loop_wait /home/elmarco/src/qemu/util/main-loop.c:261
    #15 0x55ca909275fa in main_loop_wait /home/elmarco/src/qemu/util/main-loop.c:515
    #16 0x55ca8fc1c2a4 in main_loop /home/elmarco/src/qemu/vl.c:1942
    #17 0x55ca8fc2eb3a in main /home/elmarco/src/qemu/vl.c:4724
    #18 0x7f60e4082009 in __libc_start_main (/lib64/libc.so.6+0x21009)

Indirect leak of 45 byte(s) in 1 object(s) allocated from:
    #0 0x7f60efba1850 in malloc (/lib64/libasan.so.4+0xde850)
    #1 0x7f60eef3cf0c in g_malloc ../glib/gmem.c:94
    #2 0x7f60eef3d1cf in g_malloc_n ../glib/gmem.c:331
    #3 0x7f60eef596eb in g_strdup ../glib/gstrfuncs.c:363
    #4 0x55ca90947085 in error_copy /home/elmarco/src/qemu/util/error.c:204
    #5 0x55ca9037a30f in migrate_set_error /home/elmarco/src/qemu/migration/migration.c:1139
    #6 0x55ca9037a462 in migrate_fd_error /home/elmarco/src/qemu/migration/migration.c:1150
    #7 0x55ca9038162b in migrate_fd_connect /home/elmarco/src/qemu/migration/migration.c:2411
    #8 0x55ca90386e41 in migration_channel_connect /home/elmarco/src/qemu/migration/channel.c:81
    #9 0x55ca9038335e in socket_outgoing_migration /home/elmarco/src/qemu/migration/socket.c:85
    #10 0x55ca9083dd3a in qio_task_complete /home/elmarco/src/qemu/io/task.c:142
    #11 0x55ca9083d6cc in gio_task_thread_result /home/elmarco/src/qemu/io/task.c:88
    #12 0x7f60eef37317 in g_idle_dispatch ../glib/gmain.c:5552
    #13 0x7f60eef3490b in g_main_dispatch ../glib/gmain.c:3182
    #14 0x7f60eef357ac in g_main_context_dispatch ../glib/gmain.c:3847
    #15 0x55ca90927231 in glib_pollfds_poll /home/elmarco/src/qemu/util/main-loop.c:214
    #16 0x55ca90927420 in os_host_main_loop_wait /home/elmarco/src/qemu/util/main-loop.c:261
    #17 0x55ca909275fa in main_loop_wait /home/elmarco/src/qemu/util/main-loop.c:515
    #18 0x55ca8fc1c2a4 in main_loop /home/elmarco/src/qemu/vl.c:1942
    #19 0x55ca8fc2eb3a in main /home/elmarco/src/qemu/vl.c:4724
    #20 0x7f60e4082009 in __libc_start_main (/lib64/libc.so.6+0x21009)

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20180306170959.3921-1-marcandre.lureau@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
aik pushed a commit that referenced this issue May 15, 2018
This fixes leaks found by ASAN such as:
  GTESTER tests/test-blockjob
=================================================================
==31442==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 24 byte(s) in 1 object(s) allocated from:
    #0 0x7f88483cba38 in __interceptor_calloc (/lib64/libasan.so.4+0xdea38)
    #1 0x7f8845e1bd77 in g_malloc0 ../glib/gmem.c:129
    #2 0x7f8845e1c04b in g_malloc0_n ../glib/gmem.c:360
    #3 0x5584d2732498 in block_job_txn_new /home/elmarco/src/qemu/blockjob.c:172
    #4 0x5584d2739b28 in block_job_create /home/elmarco/src/qemu/blockjob.c:973
    #5 0x5584d270ae31 in mk_job /home/elmarco/src/qemu/tests/test-blockjob.c:34
    #6 0x5584d270b1c1 in do_test_id /home/elmarco/src/qemu/tests/test-blockjob.c:57
    #7 0x5584d270b65c in test_job_ids /home/elmarco/src/qemu/tests/test-blockjob.c:118
    #8 0x7f8845e40b69 in test_case_run ../glib/gtestutils.c:2255
    #9 0x7f8845e40f29 in g_test_run_suite_internal ../glib/gtestutils.c:2339
    #10 0x7f8845e40fd2 in g_test_run_suite_internal ../glib/gtestutils.c:2351
    #11 0x7f8845e411e9 in g_test_run_suite ../glib/gtestutils.c:2426
    #12 0x7f8845e3fe72 in g_test_run ../glib/gtestutils.c:1692
    #13 0x5584d270d6e2 in main /home/elmarco/src/qemu/tests/test-blockjob.c:377
    #14 0x7f8843641f29 in __libc_start_main (/lib64/libc.so.6+0x20f29)

Add an assert to make sure that the job doesn't have associated txn before free().

[Jeff Cody: N.B., used updated patch provided by John Snow]

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Jeff Cody <jcody@redhat.com>
aik pushed a commit that referenced this issue May 15, 2018
Free the AIO context earlier than the GMainContext (if we have) to
workaround a glib2 bug that GSource context pointer is not cleared even
if the context has already been destroyed (while it should).

The patch itself only changed the order to destroy the objects, no
functional change at all. Without this workaround, we can encounter
qmp-test hang with oob (and possibly any other use case when iothread is
used with GMainContexts):

  #0  0x00007f35ffe45334 in __lll_lock_wait () from /lib64/libpthread.so.0
  #1  0x00007f35ffe405d8 in _L_lock_854 () from /lib64/libpthread.so.0
  #2  0x00007f35ffe404a7 in pthread_mutex_lock () from /lib64/libpthread.so.0
  #3  0x00007f35fc5b9c9d in g_source_unref_internal (source=0x24f0600, context=0x7f35f0000960, have_lock=0) at gmain.c:1685
  #4  0x0000000000aa6672 in aio_context_unref (ctx=0x24f0600) at /root/qemu/util/async.c:497
  #5  0x000000000065851c in iothread_instance_finalize (obj=0x24f0380) at /root/qemu/iothread.c:129
  #6  0x0000000000962d79 in object_deinit (obj=0x24f0380, type=0x242e960) at /root/qemu/qom/object.c:462
  #7  0x0000000000962e0d in object_finalize (data=0x24f0380) at /root/qemu/qom/object.c:476
  #8  0x0000000000964146 in object_unref (obj=0x24f0380) at /root/qemu/qom/object.c:924
  #9  0x0000000000965880 in object_finalize_child_property (obj=0x24ec640, name=0x24efca0 "mon_iothread", opaque=0x24f0380) at /root/qemu/qom/object.c:1436
  #10 0x0000000000962c33 in object_property_del_child (obj=0x24ec640, child=0x24f0380, errp=0x0) at /root/qemu/qom/object.c:436
  #11 0x0000000000962d26 in object_unparent (obj=0x24f0380) at /root/qemu/qom/object.c:455
  #12 0x0000000000658f00 in iothread_destroy (iothread=0x24f0380) at /root/qemu/iothread.c:365
  #13 0x00000000004c67a8 in monitor_cleanup () at /root/qemu/monitor.c:4663
  #14 0x0000000000669e27 in main (argc=16, argv=0x7ffc8b1ae2f8, envp=0x7ffc8b1ae380) at /root/qemu/vl.c:4749

The glib2 bug is fixed in commit 26056558b ("gmain: allow
g_source_get_context() on destroyed sources", 2012-07-30), so the first
good version is glib2 2.33.10. But we still support building with
glib as old as 2.28, so we need the workaround.

Let's make sure we destroy the GSources first before its owner context
until we drop support for glib older than 2.33.10.

Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20180409083956.1780-1-peterx@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
aik pushed a commit that referenced this issue May 15, 2018
Eric Auger reported the problem days ago that OOB broke ARM when running
with libvirt:

http://lists.gnu.org/archive/html/qemu-devel/2018-03/msg06231.html

The problem was that the monitor dispatcher bottom half was bound to
qemu_aio_context now, which could be polled unexpectedly in block code.
We should keep the dispatchers run in iohandler_ctx just like what we
did before the Out-Of-Band series (chardev uses qio, and qio binds
everything with iohandler_ctx).

If without this change, QMP dispatcher might be run even before reaching
main loop in block IO path, for example, in a stack like (the ARM case,
"cont" command handler run even during machine init phase):

        #0  qmp_cont ()
        #1  0x00000000006bd210 in qmp_marshal_cont ()
        #2  0x0000000000ac05c4 in do_qmp_dispatch ()
        #3  0x0000000000ac07a0 in qmp_dispatch ()
        #4  0x0000000000472d60 in monitor_qmp_dispatch_one ()
        #5  0x000000000047302c in monitor_qmp_bh_dispatcher ()
        #6  0x0000000000acf374 in aio_bh_call ()
        #7  0x0000000000acf428 in aio_bh_poll ()
        #8  0x0000000000ad5110 in aio_poll ()
        #9  0x0000000000a08ab8 in blk_prw ()
        #10 0x0000000000a091c4 in blk_pread ()
        #11 0x0000000000734f94 in pflash_cfi01_realize ()
        #12 0x000000000075a3a4 in device_set_realized ()
        #13 0x00000000009a26cc in property_set_bool ()
        #14 0x00000000009a0a40 in object_property_set ()
        #15 0x00000000009a3a08 in object_property_set_qobject ()
        #16 0x00000000009a0c8c in object_property_set_bool ()
        #17 0x0000000000758f94 in qdev_init_nofail ()
        #18 0x000000000058e190 in create_one_flash ()
        #19 0x000000000058e2f4 in create_flash ()
        #20 0x00000000005902f0 in machvirt_init ()
        #21 0x00000000007635cc in machine_run_board_init ()
        #22 0x00000000006b135c in main ()

Actually the problem is more severe than that.  After we switched to the
qemu AIO handler it means the monitor dispatcher code can even be called
with nested aio_poll(), then it can be an explicit aio_poll() inside
another main loop aio_poll() which could be racy too; breaking code
like TPM and 9p that use nested event loops.

Switch to use the iohandler_ctx for monitor dispatchers.

My sincere thanks to Eric Auger who offered great help during both
debugging and verifying the problem.  The ARM test was carried out by
applying this patch upon QEMU 2.12.0-rc0 and problem is gone after the
patch.

A quick test of mine shows that after this patch applied we can pass all
raw iotests even with OOB on by default.

CC: Eric Blake <eblake@redhat.com>
CC: Markus Armbruster <armbru@redhat.com>
CC: Stefan Hajnoczi <stefanha@redhat.com>
CC: Fam Zheng <famz@redhat.com>
Reported-by: Eric Auger <eric.auger@redhat.com>
Tested-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20180410044942.17059-1-peterx@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
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