[libvirt] [PATCH 2/5] qemu: minor monitor lock cleanups
If virCondInit fails (okay, so that's unlikely), then we end up
attempting a virObjectUnlock() on the cleanup path, even though
we don't hold a lock. This is not guaranteed to be safe. While
at it, I noticed a couple places where we were referencing mon->fd
outside locks.
* src/qemu/qemu_monitor.c (qemuMonitorOpenInternal): Minimize lock
duration. mon-watch doesn't need clean up on error.
(qemuMonitorGetBlockExtent, qemuMonitorBlockResize): Don't
dereference fd outside of lock.
---
src/qemu/qemu_monitor.c | 12 ++++--------
1 file changed, 4 insertions(+), 8 deletions(-)
diff --git a/src/qemu/qemu_monitor.c b/src/qemu/qemu_monitor.c
index 7f4a7a0..40eea75 100644
--- a/src/qemu/qemu_monitor.c
+++ b/src/qemu/qemu_monitor.c
@@ -717,7 +717,6 @@ qemuMonitorOpenInternal(virDomainObjPtr vm,
if (json)
mon->wait_greeting = 1;
mon->cb = cb;
- virObjectLock(mon);
if (virSetCloseExec(mon->fd) < 0) {
virReportError(VIR_ERR_INTERNAL_ERROR,
@@ -731,6 +730,7 @@ qemuMonitorOpenInternal(virDomainObjPtr vm,
}
+ virObjectLock(mon);
virObjectRef(mon);
if ((mon->watch = virEventAddHandle(mon->fd,
VIR_EVENT_HANDLE_HANGUP |
@@ -740,6 +740,7 @@ qemuMonitorOpenInternal(virDomainObjPtr vm,
mon,
virObjectFreeCallback)) < 0) {
virObjectUnref(mon);
+ virObjectUnlock(mon);
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("unable to register monitor events"));
goto cleanup;
@@ -759,11 +760,8 @@ cleanup:
* so kill the callbacks now.
*/
mon->cb = NULL;
- virObjectUnlock(mon);
/* The caller owns 'fd' on failure */
mon->fd = -1;
- if (mon->watch)
- virEventRemoveHandle(mon->watch);
qemuMonitorClose(mon);
return NULL;
}
@@ -1508,8 +1506,7 @@ int qemuMonitorGetBlockExtent(qemuMonitorPtr mon,
unsigned long long *extent)
{
int ret;
- VIR_DEBUG("mon=%p, fd=%d, dev_name=%p",
- mon, mon->fd, dev_name);
+ VIR_DEBUG("mon=%p, dev_name=%p", mon, dev_name);
if (mon->json)
ret = qemuMonitorJSONGetBlockExtent(mon, dev_name, extent);
@@ -1524,8 +1521,7 @@ int qemuMonitorBlockResize(qemuMonitorPtr mon,
unsigned long long size)
{
int ret;
- VIR_DEBUG("mon=%p, fd=%d, devname=%p size=%llu",
- mon, mon->fd, device, size);
+ VIR_DEBUG("mon=%p, devname=%p size=%llu", mon, device, size);
if (mon->json)
ret = qemuMonitorJSONBlockResize(mon, device, size);
--
1.8.1.2