[libvirt] [PATCH] Fix memory leak in qemuBuildDriveStr()

[Nehal J Wani]

On Thu, Dec 5, 2013 at 2:17 AM, Eric Blake <eblake at redhat.com> wrote:
> On 12/04/2013 01:23 PM, Nehal J Wani wrote:
>> This patch fixes memory leaks reported by valgrind on running qemuxml2argvtest
>>
>> Most of them are of the form:
>>
>> ==24777== 15 bytes in 1 blocks are definitely lost in loss record 39 of 129
>> ==24777==    at 0x4A0887C: malloc (vg_replace_malloc.c:270)
>> ==24777==    by 0x341F485E21: strdup (strdup.c:42)
>> ==24777==    by 0x4CADE5F: virStrdup (virstring.c:554)
>> ==24777==    by 0x4362B6: qemuBuildDriveStr (qemu_command.c:3848)
>> ==24777==    by 0x43EF73: qemuBuildCommandLine (qemu_command.c:8500)
>> ==24777==    by 0x426670: testCompareXMLToArgvHelper (qemuxml2argvtest.c:350)
>> ==24777==    by 0x427C01: virtTestRun (testutils.c:138)
>> ==24777==    by 0x41DDB5: mymain (qemuxml2argvtest.c:658)
>> ==24777==    by 0x4282A2: virtTestMain (testutils.c:593)
>> ==24777==    by 0x341F421A04: (below main) (libc-start.c:225)
>> ==24777==
>
> Correct that it is a leak, but it seems like this patch is overkill in
> the number of lines touched, and still has leaks on error cases.
>
> I think we want this instead:
>
> diff --git i/src/qemu/qemu_command.c w/src/qemu/qemu_command.c
> index 768fdc4..9539be7 100644
> --- i/src/qemu/qemu_command.c
> +++ w/src/qemu/qemu_command.c
> @@ -4063,6 +4063,7 @@ qemuBuildDriveStr(virConnectPtr conn,
>
>          virBufferEscape(&opt, ',', ",", "%s,", source);
>      }
> +    VIR_FREE(source);
>
>      if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_DEVICE))
>          virBufferAddLit(&opt, "if=none");
> @@ -4274,6 +4275,7 @@ qemuBuildDriveStr(virConnectPtr conn,
>      return virBufferContentAndReset(&opt);
>
>  error:
> +    VIR_FREE(source);
>      virBufferFreeAndReset(&opt);
>      return NULL;
>  }
>
>
> --
> Eric Blake   eblake redhat com    +1-919-301-3266
> Libvirt virtualization library http://libvirt.org
>

Sounds reasonable. Thanks.


-- 
Nehal J Wani