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@entry=0x7f4ef4000d20, msg=msg@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@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@xxxxxxxxxxxxx>
---
src/qemu/qemu_driver.c | 17 +++++++++++------
1 file changed, 11 insertions(+), 6 deletions(-)
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index a82e58b..55b9566 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -18978,7 +18978,7 @@ qemuDomainGetStatsVcpu(virQEMUDriverPtr driver,
virDomainObjPtr dom,
virDomainStatsRecordPtr record,
int *maxparams,
- unsigned int privflags ATTRIBUTE_UNUSED)
+ unsigned int privflags)
{
size_t i;
int ret = -1;
@@ -19005,10 +19005,15 @@ qemuDomainGetStatsVcpu(virQEMUDriverPtr driver,
VIR_ALLOC_N(cpuwait, virDomainDefGetVcpus(dom->def)) < 0)
goto cleanup;
- if (qemuDomainRefreshVcpuHalted(driver, dom,
- QEMU_ASYNC_JOB_NONE) == 0 &&
- VIR_ALLOC_N(cpuhalted, virDomainDefGetVcpus(dom->def)) < 0)
- goto cleanup;
+ if (HAVE_JOB(privflags) && virDomainObjIsActive(dom)) {
+ if (qemuDomainRefreshVcpuHalted(driver, dom,
+ QEMU_ASYNC_JOB_NONE) < 0) {
+ /* it's ok to be silent and go ahead, because halted vcpu info
+ * wasn't here from the beginning */
+ virResetLastError();
+ } else if (VIR_ALLOC_N(cpuhalted, virDomainDefGetVcpus(dom->def)) < 0)
+ goto cleanup;
+ }
if (qemuDomainHelperGetVcpus(dom, cpuinfo, cpuwait,
virDomainDefGetVcpus(dom->def),
@@ -19462,7 +19467,7 @@ static struct qemuDomainGetStatsWorker qemuDomainGetStatsWorkers[] = {
{ qemuDomainGetStatsState, VIR_DOMAIN_STATS_STATE, false },
{ qemuDomainGetStatsCpu, VIR_DOMAIN_STATS_CPU_TOTAL, false },
{ qemuDomainGetStatsBalloon, VIR_DOMAIN_STATS_BALLOON, true },
- { qemuDomainGetStatsVcpu, VIR_DOMAIN_STATS_VCPU, false },
+ { qemuDomainGetStatsVcpu, VIR_DOMAIN_STATS_VCPU, true },
{ qemuDomainGetStatsInterface, VIR_DOMAIN_STATS_INTERFACE, false },
{ qemuDomainGetStatsBlock, VIR_DOMAIN_STATS_BLOCK, true },
{ qemuDomainGetStatsPerf, VIR_DOMAIN_STATS_PERF, false },
--
2.4.11
--
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