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

[Eric Blake]

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

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