[libvirt] [PATCH 2/3] virpci: Fix memleak in virPCIDeviceIterDevices

[Michal Privoznik]

On 1/23/19 5:24 PM, Erik Skultety wrote:
> On Wed, Jan 23, 2019 at 04:45:07PM +0100, Michal Privoznik wrote:
>> This partially reverts 00dc991ca167302c7a72f4fb16be061d05b12a32.
>>
>>  2,030 (1,456 direct, 574 indirect) bytes in 14 blocks are definitely lost in loss record 77 of 80
>>     at 0x4C30E96: calloc (vg_replace_malloc.c:711)
>>     by 0x50F83AA: virAlloc (viralloc.c:143)
>>     by 0x5178DFA: virPCIDeviceNew (virpci.c:1753)
>>     by 0x51753E9: virPCIDeviceIterDevices (virpci.c:468)
>>     by 0x5175EB5: virPCIDeviceGetParent (virpci.c:759)
>>     by 0x517AB55: virPCIDeviceIsBehindSwitchLackingACS (virpci.c:2476)
>>     by 0x517AC24: virPCIDeviceIsAssignable (virpci.c:2494)
>>     by 0x10BF27: testVirPCIDeviceIsAssignable (virpcitest.c:229)
>>     by 0x10D14C: virTestRun (testutils.c:174)
>>     by 0x10C535: mymain (virpcitest.c:422)
>>     by 0x10F1B6: virTestMain (testutils.c:1112)
>>     by 0x10CF93: main (virpcitest.c:455)
>>
>> Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
>> ---
>>  src/util/virpci.c | 2 ++
>>  1 file changed, 2 insertions(+)
>>
>> diff --git a/src/util/virpci.c b/src/util/virpci.c
>> index ef578bf774..fb22460bf5 100644
>> --- a/src/util/virpci.c
>> +++ b/src/util/virpci.c
>> @@ -482,6 +482,8 @@ virPCIDeviceIterDevices(virPCIDeviceIterPredicate predicate,
>>              *matched = check;
> 
> I think that instead of adding a new condition block, we could do VIR_STEAL_PTR
> ^here and then...
> 
>>              ret = 1;
>>              break;
>> +        } else {
>> +            virPCIDeviceFree(check);
>>          }
> 
> do virPCIDeviceFree(check) unconditionally. IMHO it would also look more clean.

Or, even better, @check can be declared as VIR_AUTOPTR(virPCIDevice),
VIR_STREAL_PTR can be used to set @matched and then all
virPCIDeviceFree() calls can be removed. Does this work for you?

diff --git c/src/util/virpci.c w/src/util/virpci.c
index ef578bf774..017fe72f19 100644
--- c/src/util/virpci.c
+++ w/src/util/virpci.c
@@ -449,7 +449,7 @@ virPCIDeviceIterDevices(virPCIDeviceIterPredicate predicate,
 
     while ((ret = virDirRead(dir, &entry, PCI_SYSFS "devices")) > 0) {
         unsigned int domain, bus, slot, function;
-        virPCIDevicePtr check;
+        VIR_AUTOPTR(virPCIDevice) check = NULL;
         char *tmp;
 
         /* expected format: <domain>:<bus>:<slot>.<function> */
@@ -474,12 +474,11 @@ virPCIDeviceIterDevices(virPCIDeviceIterPredicate predicate,
         rc = predicate(dev, check, data);
         if (rc < 0) {
             /* the predicate returned an error, bail */
-            virPCIDeviceFree(check);
             ret = -1;
             break;
         } else if (rc == 1) {
             VIR_DEBUG("%s %s: iter matched on %s", dev->id, dev->name, check->name);
-            *matched = check;
+            VIR_STEAL_PTR(*matched, check);
             ret = 1;
             break;
         }

Michal