We found a exception when libvirt occurrs segmentation fault.
thread 1 is waiting object lock in qemuConnectMonitor,
qemu process exits and sends EOF event as well, so thread 2 invokes
qemuMonitorLastError but pointer mon is NULL.
Signed-off-by: Xu Yandong <xuyandong2@huawei.com>
---
src/qemu/qemu_monitor.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/src/qemu/qemu_monitor.c b/src/qemu/qemu_monitor.c
index aa230b3306..28f18391a5 100644
--- a/src/qemu/qemu_monitor.c
+++ b/src/qemu/qemu_monitor.c
@@ -1103,7 +1103,7 @@ qemuMonitorSend(qemuMonitorPtr mon,
virErrorPtr
qemuMonitorLastError(qemuMonitorPtr mon)
{
- if (mon->lastError.code == VIR_ERR_OK)
+ if (!mon || mon->lastError.code == VIR_ERR_OK)
return NULL;
return virErrorCopyNew(&mon->lastError);
--
2.18.1
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On 9/19/19 5:01 AM, Xu Yandong wrote: > We found a exception when libvirt occurrs segmentation fault. > thread 1 is waiting object lock in qemuConnectMonitor, > qemu process exits and sends EOF event as well, so thread 2 invokes > qemuMonitorLastError but pointer mon is NULL. > > Signed-off-by: Xu Yandong <xuyandong2@huawei.com> > --- Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com> > src/qemu/qemu_monitor.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/src/qemu/qemu_monitor.c b/src/qemu/qemu_monitor.c > index aa230b3306..28f18391a5 100644 > --- a/src/qemu/qemu_monitor.c > +++ b/src/qemu/qemu_monitor.c > @@ -1103,7 +1103,7 @@ qemuMonitorSend(qemuMonitorPtr mon, > virErrorPtr > qemuMonitorLastError(qemuMonitorPtr mon) > { > - if (mon->lastError.code == VIR_ERR_OK) > + if (!mon || mon->lastError.code == VIR_ERR_OK) > return NULL; > > return virErrorCopyNew(&mon->lastError); -- libvir-list mailing list libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
On 9/19/19 10:01 AM, Xu Yandong wrote: > We found a exception when libvirt occurrs segmentation fault. > thread 1 is waiting object lock in qemuConnectMonitor, > qemu process exits and sends EOF event as well, so thread 2 invokes > qemuMonitorLastError but pointer mon is NULL. > > Signed-off-by: Xu Yandong <xuyandong2@huawei.com> > --- > src/qemu/qemu_monitor.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/src/qemu/qemu_monitor.c b/src/qemu/qemu_monitor.c > index aa230b3306..28f18391a5 100644 > --- a/src/qemu/qemu_monitor.c > +++ b/src/qemu/qemu_monitor.c > @@ -1103,7 +1103,7 @@ qemuMonitorSend(qemuMonitorPtr mon, > virErrorPtr > qemuMonitorLastError(qemuMonitorPtr mon) > { > - if (mon->lastError.code == VIR_ERR_OK) > + if (!mon || mon->lastError.code == VIR_ERR_OK) > return NULL; > > return virErrorCopyNew(&mon->lastError); > This works, but I think we need a better approach. The problem is, we register monitor FD into our event loop with unlocked @vm and only after that we try to lock @vm back and set priv->mon = mon (this is all done in qemuConnectMonitor()). I have better fix in mind but I have to run now, will post it tomorrow, if that's okay with you. Michal -- libvir-list mailing list libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
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