[libvirt] [PATCH 3/3] virQEMUCapsSetHostModel: Free cpuData before setting it

[Jiri Denemark]

On Thu, May 31, 2018 at 10:06:37 +0200, Michal Privoznik wrote:
> On 05/30/2018 06:57 PM, Peter Krempa wrote:
> > On Wed, May 30, 2018 at 18:04:29 +0200, Michal Privoznik wrote:
> >> While this leak happens in tests only, it is still worth fixing.
> >>
> >> ==12962== 2,035 (104 direct, 1,931 indirect) bytes in 1 blocks are definitely lost in loss record 325 of 331
> >> ==12962==    at 0x4C2CF26: calloc (vg_replace_malloc.c:711)
> >> ==12962==    by 0x5D285D5: virAlloc (viralloc.c:144)
> >> ==12962==    by 0x5E823EB: virCPUGetHost (cpu.c:411)
> >> ==12962==    by 0x56DE953: virQEMUCapsInitHostCPUModel (qemu_capabilities.c:2874)
> >> ==12962==    by 0x56E062F: virQEMUCapsLoadCache (qemu_capabilities.c:3435)
> >> ==12962==    by 0x13802F: qemuTestParseCapabilitiesArch (testutilsqemu.c:500)
> >> ==12962==    by 0x1371F0: mymain (qemuxml2argvtest.c:2871)
> >> ==12962==    by 0x13AD0B: virTestMain (testutils.c:1120)
> >> ==12962==    by 0x1372FD: main (qemuxml2argvtest.c:2883)
> >>
> >> Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
> >> ---
> >>  src/qemu/qemu_capabilities.c | 4 ++++
> >>  1 file changed, 4 insertions(+)
> >>
> >> diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c
> >> index e2e76e4dd8..9ec9089d5b 100644
> >> --- a/src/qemu/qemu_capabilities.c
> >> +++ b/src/qemu/qemu_capabilities.c
> >> @@ -1857,6 +1857,10 @@ virQEMUCapsSetHostModel(virQEMUCapsPtr qemuCaps,
> >>  {
> >>      virQEMUCapsHostCPUDataPtr cpuData = virQEMUCapsGetHostCPUData(qemuCaps, type);
> >>  
> >> +    virCPUDefFree(cpuData->reported);
> >> +    virCPUDefFree(cpuData->migratable);
> >> +    virCPUDefFree(cpuData->full);
> > 
> > This looks fishy. The test code always unrefs the qemuCaps object, so
> > there should be no leak. Could you please elaborate on how this happens?
> 
> Thing is, qemuTestParseCapabilitiesArch() calls virQEMUCapsLoadCache()
> (which exists only for sake of tests) which does two things:
> 
> 1) roughly in the middle it calls virQEMUCapsLoadHostCPUModelInfo()
> where cpuData is firstly allocated

virQEMUCapsLoadHostCPUModelInfo calls virQEMUCapsSetCPUModelInfo which
sets cpuData->info

> 2) at the end it calls virQEMUCapsInitHostCPUModel() which overwrites
> whatever was loaded in 1).

while virQEMUCapsInitHostCPUModel fills cpuData->reported,
cpuData->migratable, and cpuData->full using the data from
cpuData->info.

It must be something else which causes the leak.

Jirka