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b362938e57
libvirt/src/remote
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Daniel P. Berrange b362938e57 remote: Avoid the thread race condition 
https://bugzilla.redhat.com/show_bug.cgi?id=866524

Since the virConnect object is not locked wholely when doing
virConenctDispose, a thread can get the lock and thus might
cause the race.

Detected by valgrind:

==23687== Invalid read of size 4
==23687==    at 0x38BAA091EC: pthread_mutex_lock (pthread_mutex_lock.c:61)
==23687==    by 0x3FBA919E36: remoteClientCloseFunc (remote_driver.c:337)
==23687==    by 0x3FBA936BF2: virNetClientCloseLocked (virnetclient.c:688)
==23687==    by 0x3FBA9390D8: virNetClientIncomingEvent (virnetclient.c:1859)
==23687==    by 0x3FBA851AAE: virEventPollRunOnce (event_poll.c:485)
==23687==    by 0x3FBA850846: virEventRunDefaultImpl (event.c:247)
==23687==    by 0x40CD61: vshEventLoop (virsh.c:2128)
==23687==    by 0x3FBA8626F8: virThreadHelper (threads-pthread.c:161)
==23687==    by 0x38BAA077F0: start_thread (pthread_create.c:301)
==23687==    by 0x33F68E570C: clone (clone.S:115)
==23687==  Address 0x4ca94e0 is 144 bytes inside a block of size 312 free'd
==23687==    at 0x4A0595D: free (vg_replace_malloc.c:366)
==23687==    by 0x3FBA8588B8: virFree (memory.c:309)
==23687==    by 0x3FBA86AAFC: virObjectUnref (virobject.c:145)
==23687==    by 0x3FBA8EA767: virConnectClose (libvirt.c:1458)
==23687==    by 0x40C8B8: vshDeinit (virsh.c:2584)
==23687==    by 0x41071E: main (virsh.c:3022)

The above race is caused by the eventLoop thread tries to handle
the net client event by calling the callback set by:
    virNetClientSetCloseCallback(priv->client,
                                 remoteClientCloseFunc,
                                 conn, NULL);

I.E. remoteClientCloseFunc, which lock/unlock the virConnect object.

This patch is to fix the bug by setting the callback to NULL when
doRemoteClose.
2012-12-06 00:43:18 +08:00
..
qemu_protocol.x maint: fix up copyright notice inconsistencies 2012-09-20 16:30:55 -06:00
remote_driver.c remote: Avoid the thread race condition 2012-12-06 00:43:18 +08:00
remote_driver.h maint: fix up copyright notice inconsistencies 2012-09-20 16:30:55 -06:00
remote_protocol.x Specify remote protocol for virDomainSendProcessSignal 2012-11-29 15:50:12 +00:00