From 541e9ae6d4290b9004ed73648ea663563b329b3d Mon Sep 17 00:00:00 2001 From: Jim Fehlig Date: Fri, 5 Aug 2016 15:23:47 -0600 Subject: [PATCH] cpu_x86: fix libvirtd crash when host cpu vendor is not available When starting a guest and copying host vendor cpuid to the guest cpu, libvirtd would crash if the host cpu contained a NULL vendor field. Avoid the crash by checking for a valid vendor in the host cpu before copying the cpuid to the guest cpu. For completeness, here is a backtrace from the crash (gdb) bt f0 0x00007ffff739bf33 in x86DataCpuid (cpuid=0x8, cpuid=0x8, data=data@entry=0x7fffb800ee78) at cpu/cpu_x86.c:287 f1 virCPUx86DataAddCPUID (data=data@entry=0x7fffb800ee78, cpuid=0x8) at cpu/cpu_x86.c:355 f2 0x00007ffff739ef47 in x86Compute (host=, cpu=0x7fffb8000cc0, guest=0x7fffecca7348, message=) at cpu/cpu_x86.c:1580 f3 0x00007fffd2b38e53 in qemuBuildCpuModelArgStr (migrating=false, hasHwVirt=, qemuCaps=0x7fffb8001040, buf=0x7fffecca7360, def=0x7fffc400ce20, driver=0x1c) at qemu/qemu_command.c:6283 f4 qemuBuildCpuCommandLine (cmd=cmd@entry=0x7fffb8002f60, driver=driver@entry=0x7fffc80882c0, def=def@entry=0x7fffc400ce20, qemuCaps=qemuCaps@entry=0x7fffb8001040, migrating=) at qemu/qemu_command.c:6445 (gdb) f2 (gdb) p *host_model $23 = {name = 0x7fffb800ec50 "qemu64", vendor = 0x0, signature = 0, data = { len = 2, data = 0x7fffb800e720}} --- src/cpu/cpu_x86.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/cpu/cpu_x86.c b/src/cpu/cpu_x86.c index 670b02ed6d..ee5b57d6fc 100644 --- a/src/cpu/cpu_x86.c +++ b/src/cpu/cpu_x86.c @@ -1592,7 +1592,7 @@ x86Compute(virCPUDefPtr host, if (!(guest_model = x86ModelCopy(host_model))) goto error; - if (cpu->vendor && + if (cpu->vendor && host_model->vendor && virCPUx86DataAddCPUID(&guest_model->data, &host_model->vendor->cpuid) < 0) goto error; -- GitLab