[libvirt] nwfilter: grab driver lock earlier during init (bz96649)
This patch is in relation to Bug 966449:
https://bugzilla.redhat.com/show_bug.cgi?id=966449
Below is a possible patch addressing the coredump.
Thread 1 must be calling nwfilterDriverRemoveDBusMatches(). It does so
with nwfilterDriverLock held. In the patch below I am now moving the
nwfilterDriverLock(driverState) further up so that the initialization,
which seems to either take a long time or is entirely stuck, occurs with
the lock held and the shutdown cannot occur at the same time.
To avoid having to make the nwfilterDriverLock lockable multiple times /
recursive I changed the virNWFilterDriverIsWatchingFirewallD to take as
an argument whether it has to grab that lock. There's only a single
caller at the moment that calls this function during initialization. We
could remove this lock entirely and maybe append to the name of the
function NoLock (?).
---
src/nwfilter/nwfilter_driver.c | 18 +++++++++++++-----
src/nwfilter/nwfilter_driver.h | 2 +-
src/nwfilter/nwfilter_ebiptables_driver.c | 7 ++++++-
3 files changed, 20 insertions(+), 7 deletions(-)
Index: libvirt/src/nwfilter/nwfilter_driver.c
===================================================================
--- libvirt.orig/src/nwfilter/nwfilter_driver.c
+++ libvirt/src/nwfilter/nwfilter_driver.c
@@ -191,6 +191,8 @@ nwfilterStateInitialize(bool privileged,
if (!privileged)
return 0;
+ nwfilterDriverLock(driverState);
+
if (virNWFilterIPAddrMapInit() < 0)
goto err_free_driverstate;
if (virNWFilterLearnInit() < 0)
@@ -203,8 +205,6 @@ nwfilterStateInitialize(bool privileged,
if (virNWFilterConfLayerInit(virNWFilterDomainFWUpdateCB) < 0)
goto err_techdrivers_shutdown;
- nwfilterDriverLock(driverState);
-
/*
* startup the DBus late so we don't get a reload signal while
* initializing
@@ -309,21 +309,29 @@ nwfilterStateReload(void) {
/**
* virNWFilterIsWatchingFirewallD:
*
+ * @needDriverLock: Provide 'true' if this function needs to grab
+ * the nwfilter driver lock, 'false' otherwise,
+ * which may be the case during initialization
+ *
* Checks if the nwfilter has the DBus watches for FirewallD installed.
*
* Returns true if it is watching firewalld, false otherwise
*/
bool
-virNWFilterDriverIsWatchingFirewallD(void)
+virNWFilterDriverIsWatchingFirewallD(bool needDriverLock)
{
bool ret;
if (!driverState)
return false;
- nwfilterDriverLock(driverState);
+ if (needDriverLock)
+ nwfilterDriverLock(driverState);
+
ret = driverState->watchingFirewallD;
- nwfilterDriverUnlock(driverState);
+
+ if (needDriverLock)
+ nwfilterDriverUnlock(driverState);
return ret;
}
Index: libvirt/src/nwfilter/nwfilter_driver.h
===================================================================
--- libvirt.orig/src/nwfilter/nwfilter_driver.h
+++ libvirt/src/nwfilter/nwfilter_driver.h
@@ -33,6 +33,6 @@
int nwfilterRegister(void);
-bool virNWFilterDriverIsWatchingFirewallD(void);
+bool virNWFilterDriverIsWatchingFirewallD(bool needDriverLock);
#endif /* __VIR_NWFILTER_DRIVER_H__ */
Index: libvirt/src/nwfilter/nwfilter_ebiptables_driver.c
===================================================================
--- libvirt.orig/src/nwfilter/nwfilter_ebiptables_driver.c
+++ libvirt/src/nwfilter/nwfilter_ebiptables_driver.c
@@ -4191,7 +4191,12 @@ ebiptablesDriverInitWithFirewallD(void)
int status;
int ret = -1;
- if (!virNWFilterDriverIsWatchingFirewallD())
+ /*
+ * check whether we are watching firewalld
+ * Since we call this function during initialization we won't need
+ * to have it get the lock, so we pass 'false'.
+ */
+ if (!virNWFilterDriverIsWatchingFirewallD(false))
return -1;
firewall_cmd_path = virFindFileInPath("firewall-cmd");