[libvirt] [PATCH] Fix potential crash when saving guests

[Eric Blake]

On 06/30/2011 08:10 AM, Daniel P. Berrange wrote:
> The qemudDomainSaveFlag method will call EndJob on the 'vm'
> object it is passed in. This can result in the 'vm' object
> being free'd if the last reference is removed. Thus no caller
> of 'qemudDomainSaveFlag' must *ever* reference 'vm' again
> upon return.
> 
> Unfortunately qemudDomainSave and qemuDomainManagedSave
> both call 'virDomainObjUnlock', which can result in a
> crash. This is non-deterministic since it involves a race
> with the monitor I/O thread.
> 
> Fix this by making qemudDomainSaveFlag responsible for
> calling virDomainObjUnlock instead.
> 
> * src/qemu/qemu_driver.c: Fix potential use after free
>   when saving guests
> ---
>  src/qemu/qemu_driver.c |    9 ++++++++-
>  1 files changed, 8 insertions(+), 1 deletions(-)

Nice analysis, and probably something that people have hit before.

ACK.

-- 
Eric Blake   eblake at redhat.com    +1-801-349-2682
Libvirt virtualization library http://libvirt.org

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