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To:Laine Stump From:Eric Blake Subject:Re: [libvirt] [PATCH] snapshot: fix memory leak on error Date:Thu, 05 Apr 2012 14:54:26 -0600
 

On 04/05/2012 01:34 PM, Laine Stump wrote:
> On 04/05/2012 03:16 PM, Eric Blake wrote:
>> Leak introduced in commit 0436d32. If we allocate an actions array,
>> but fail early enough to never consume it with the qemu monitor
>> transaction call, we leaked memory.
>>
>> * src/qemu/qemu_driver.c (qemuDomainSnapshotCreateDiskActive):
>> Free actions array on failure.
>> ---
>> src/qemu/qemu_driver.c | 2 ++
>> 1 files changed, 2 insertions(+), 0 deletions(-)
>>
>> diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
>> index b29029e..a214593 100644
>> --- a/src/qemu/qemu_driver.c
>> +++ b/src/qemu/qemu_driver.c
>> @@ -10132,6 +10132,8 @@ qemuDomainSnapshotCreateDiskActive(virConnectPtr conn,
>> if (actions) {
>> if (ret == 0)
>> ret = qemuMonitorTransaction(priv->mon, actions);
>> + else
>> + virJSONValueFree(actions);
>> if (ret < 0) {
>> /* Transaction failed; undo the changes to vm. */
>> bool need_unlink = !(flags & VIR_DOMAIN_SNAPSHOT_CREATE_REUSE_EXT);
>
> ACK.

Shoot - I just realized that I missed a spot. The semantics of
consuming an array are a bit confusing, since it means everyone along
the chain must participate in those semantics. Better is to make the
person that allocates also do the free, but that requires a bit more
hacking to avoid double-freeing things when recursively deleting the
'transaction' JSON command that wraps the actions array.

v2 coming up.

--
Eric Blake eblake@redhat.com +1-919-301-3266
Libvirt virtualization library http://libvirt.org