[libvirt] [PATCH 2/2] mdev: Fix daemon crash on domain shutdown after reconnect

[Laine Stump]

On 04/28/2017 03:46 AM, Erik Skultety wrote:
> The problem resides in virHostdevUpdateActiveMediatedDevices which gets
> called during qemuProcessReconnect. The issue here is that
> virMediatedDeviceListAdd takes a pointer to the item to be added to the
> list to which VIR_APPEND_ELEMENT is used, which also clears the pointer.
> However, in this case only the local copy of the pointer got cleared,
> leaving the original pointing to valid memory. To sum it up, during
> cleanup phase, the original pointer is freed and the daemon crashes
> basically any time it would access it.
> 
> Backtrace:
> 0x00007ffff3ccdeba in __strcmp_sse2_unaligned
> 0x00007ffff72a444a in virMediatedDeviceListFindIndex
> 0x00007ffff7241446 in virHostdevReAttachMediatedDevices
> 0x00007fffc60215d9 in qemuHostdevReAttachMediatedDevices
> 0x00007fffc60216dc in qemuHostdevReAttachDomainDevices
> 0x00007fffc6046e6f in qemuProcessStop
> 0x00007fffc6091596 in processMonitorEOFEvent
> 0x00007fffc6091793 in qemuProcessEventHandler
> 0x00007ffff7294bf5 in virThreadPoolWorker
> 0x00007ffff7294184 in virThreadHelper
> 0x00007ffff3fdc3c4 in start_thread () from /lib64/libpthread.so.0
> 0x00007ffff3d269cf in clone () from /lib64/libc.so.6
> 
> Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1446455
> 
> Signed-off-by: Erik Skultety <eskultet at redhat.com>

Reviewed-by: Laine Stump <laine at laine.org>

or ACK, or whatever is the new accepted hotness.