[libvirt] [PATCH v2] qemu: fix libvirtd crash when querying halted cpus info

[Maxim Nestratov]

15-Nov-16 16:44, Maxim Nestratov пишет:

> It was introduced by commit 7a51d9ebb, which started to use
> monitor commands without job acquiring, which is unsafe and leads
> to simultaneous access to vm->mon structure by different threads.
>
> Crash backtrace is the following (shortened):
>
> Program received signal SIGSEGV, Segmentation fault.
> qemuMonitorSend (mon=mon at entry=0x7f4ef4000d20, msg=msg at entry=0x7f4f18e78640) at qemu/qemu_monitor.c:1011
> 1011        while (!mon->msg->finished) {
>
> 0  qemuMonitorSend () at qemu/qemu_monitor.c:1011
> 1  0x00007f691abdc720 in qemuMonitorJSONCommandWithFd () at qemu/qemu_monitor_json.c:298
> 2  0x00007f691abde64a in qemuMonitorJSONCommand at qemu/qemu_monitor_json.c:328
> 3  qemuMonitorJSONQueryCPUs at qemu/qemu_monitor_json.c:1408
> 4  0x00007f691abcaebd in qemuMonitorGetCPUInfo g at entry=false) at qemu/qemu_monitor.c:1931
> 5  0x00007f691ab96863 in qemuDomainRefreshVcpuHalted at qemu/qemu_domain.c:6309
> 6  0x00007f691ac0af99 in qemuDomainGetStatsVcpu at qemu/qemu_driver.c:18945
> 7  0x00007f691abef921 in qemuDomainGetStats  at qemu/qemu_driver.c:19469
> 8  qemuConnectGetAllDomainStats at qemu/qemu_driver.c:19559
> 9  0x00007f693382e806 in virConnectGetAllDomainStats at libvirt-domain.c:11546
> 10 0x00007f6934470c40 in remoteDispatchConnectGetAllDomainStats at remote.c:6267
>
> (gdb) p mon->msg
> $1 = (qemuMonitorMessagePtr) 0x0
>
> This change fixes it by calling qemuDomainRefreshVcpuHalted only when job is acquired.
>
> Signed-off-by: Maxim Nestratov <mnestratov at virtuozzo.com>
> ---
>   src/qemu/qemu_driver.c | 17 +++++++++++------
>   1 file changed, 11 insertions(+), 6 deletions(-)

Ignore this version please. The next one is sent with "syntax-check".

Maxim