[libvirt] [PATCH 1/2] Make checks for inactive QEMU guest more robust
Before issuing monitor commands it is neccessary to check whether
the guest is still running. Most places use virDomainIsActive()
correctly, but a few relied on 'priv->mon != NULL'. In theory
these should be equivalent, but the release of the last reference
count on priv->mon can be delayed a small amount of time until
the event handler is finally deregistered. A further ref counting
bug also means that priv->mon might be never released. In such a
case, code could mistakenly issue a monitor command and wait for
a response that will never arrive, effectively leaving the QEMU
driver waiting on virCondWait() forever..
To protect against these possibilities, make sure all code uses
virDomainIsActive(), not 'priv->mon != NULL'
* src/qemu/qemu_driver.c: Replace 'priv->mon != NULL' with
calls to 'priv->mon != NULL'()
---
src/qemu/qemu_driver.c | 10 +++++-----
1 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index bc8dcfa..c837611 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -5225,7 +5225,7 @@ static int qemudDomainSaveFlag(virDomainPtr dom, const char *path,
endjob:
if (vm) {
if (ret != 0) {
- if (header.was_running && priv->mon) {
+ if (header.was_running && virDomainObjIsActive(vm)) {
qemuDomainObjEnterMonitorWithDriver(driver, vm);
rc = qemuMonitorStartCPUs(priv->mon, dom->conn);
qemuDomainObjExitMonitorWithDriver(driver, vm);
@@ -5537,7 +5537,7 @@ endjob:
/* Since the monitor is always attached to a pty for libvirt, it
will support synchronous operations so we always get here after
the migration is complete. */
- else if (resume && paused && priv->mon) {
+ else if (resume && paused && virDomainObjIsActive(vm)) {
qemuDomainObjEnterMonitorWithDriver(driver, vm);
if (qemuMonitorStartCPUs(priv->mon, dom->conn) < 0) {
if (virGetLastError() == NULL)
@@ -7651,7 +7651,7 @@ cleanup:
return ret;
try_remove:
- if (!priv->mon)
+ if (!virDomainObjIsActive(vm))
goto cleanup;
if (vlan < 0) {
@@ -7683,7 +7683,7 @@ try_remove:
goto cleanup;
try_tapfd_close:
- if (!priv->mon)
+ if (!virDomainObjIsActive(vm))
goto cleanup;
if (tapfd_name) {
@@ -10737,7 +10737,7 @@ static int doTunnelMigrate(virDomainPtr dom,
retval = doTunnelSendAll(st, client_sock);
cancel:
- if (retval != 0 && priv->mon) {
+ if (retval != 0 && virDomainObjIsActive(vm)) {
qemuDomainObjEnterMonitorWithDriver(driver, vm);
qemuMonitorMigrateCancel(priv->mon);
qemuDomainObjExitMonitorWithDriver(driver, vm);
--
1.6.6.1