Re: [libvirt] [PATCH] qemu: Fix crash in qemucapsprobe
On Tue, Sep 27, 2016 at 08:25:05 -0400, John Ferlan wrote:
On 09/27/2016 07:47 AM, Jiri Denemark wrote:
> The qemucapsprobe helper calls virQEMUCapsInitHostCPUModel with
> caps == NULL, causing the following crash:
>
> Program received signal SIGSEGV, Segmentation fault.
> #0 0x00007ffff788775f in virQEMUCapsInitHostCPUModel
> (qemuCaps=qemuCaps@entry=0x649680, host=host@entry=0x10) at
> src/qemu/qemu_capabilities.c:2969
> #1 0x00007ffff7889dbf in virQEMUCapsNewForBinaryInternal
> (caps=caps@entry=0x0, binary=<optimized out>,
> libDir=libDir@entry=0x4033f6 "/tmp", cacheDir=cacheDir@entry=0x0,
> runUid=runUid@entry=4294967295, runGid=runGid@entry=4294967295,
> qmpOnly=true) at src/qemu/qemu_capabilities.c:4039
> #2 0x0000000000401702 in main (argc=2, argv=0x7fffffffd968) at
> tests/qemucapsprobe.c:73
>
> Signed-off-by: Jiri Denemark <jdenemar(a)redhat.com>
> ---
> src/qemu/qemu_capabilities.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
Earlier in this function there's:
if (!cacheDir)
rv = 0;
else if ((rv = virQEMUCapsInitCached(caps, qemuCaps, cacheDir)) < 0)
goto error;
virQEMUCapsInitCached will call virQEMUCapsLoadCache which will call
virQEMUCapsInitHostCPUModel(qemuCaps, &caps->host); as well.
Well, this cannot happen if caps == NULL.
So wouldn't it better to have virQEMUCapsInitHostCPUModel take
"caps" as
the parameter and then return "silently" if !caps->host ?
But this is the way I should have fixed it, since it will work better
with future changes.
Jirka