[libvirt] Potential segfault in udev driver

Dave Allan dallan at redhat.com
Mon Jan 25 18:56:15 UTC 2010

On 01/25/2010 06:37 AM, Daniel P. Berrange wrote:
> On Sun, Jan 24, 2010 at 11:07:59PM +0100, Matthias Bolte wrote:
>> udevDeviceMonitorStartup registers udevEventHandleCallback as event
>> handle, but doesn't store the returned watch id to remove it later on.
>> Also it's not clear to me whether the event handle should be register
>> for the whole lifetime of the udev driver instance or just for the
>> udevEnumerateDevices call.
> The handler should be active for the lifetime of libvirtd, since the
> udev driver has to detect hotplug/unplug events over time.
>> If for example the call to udevSetupSystemDev [1] fails
>> udevDeviceMonitorShutdown is called to cleanup, but
>> udevEventHandleCallback is still registered and may be called when
>> driverState is NULL again, resulting in a segfault in
>> udevEventHandleCallback.
>> So to solve this the udevEventHandleCallback event handle must be
>> removed at the appropriate place.
> Yes, sounds like its needs to be removed in the failure path there


Indeed, that's correct--can you submit a patch?


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