[libvirt PATCH 2/5] virNWFilterSnoopState: Prevent mutex leak

[Tim Wiederhake]

virNWFilterDHCPSnoopShutdown would never destroy the mutexes created
in virNWFilterDHCPSnoopInit. Additionally, if in virNWFilterDHCPSnoopInit
the call to virMutexInitRecursive succeeds and the call to virMutexInit
fails, this would lead to either virNWFilterSnoopState.snoopLock being
initialized twice or virNWFilterSnoopState.activeLock destroyed without
being initialized first.

This enables a later patch to use virNWFilterDHCPSnoopShutdown as a
cleanup function safely, as it is a no-op if virNWFilterSnoopState was
not yet initialized.

Signed-off-by: Tim Wiederhake <twied...@redhat.com>
---
 src/nwfilter/nwfilter_dhcpsnoop.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/src/nwfilter/nwfilter_dhcpsnoop.c 
b/src/nwfilter/nwfilter_dhcpsnoop.c
index 852840c209..d26e787453 100644
--- a/src/nwfilter/nwfilter_dhcpsnoop.c
+++ b/src/nwfilter/nwfilter_dhcpsnoop.c
@@ -1860,10 +1860,14 @@ virNWFilterDHCPSnoopInit(void)
 
     VIR_DEBUG("Initializing DHCP snooping");
 
-    if (virMutexInitRecursive(&virNWFilterSnoopState.snoopLock) < 0 ||
-        virMutexInit(&virNWFilterSnoopState.activeLock) < 0)
+    if (virMutexInitRecursive(&virNWFilterSnoopState.snoopLock) < 0)
         return -1;
 
+    if (virMutexInit(&virNWFilterSnoopState.activeLock) < 0) {
+        virMutexDestroy(&virNWFilterSnoopState.snoopLock);
+        return -1;
+    }
+
     virNWFilterSnoopState.ifnameToKey = virHashNew(NULL);
     virNWFilterSnoopState.active = virHashNew(NULL);
     virNWFilterSnoopState.snoopReqs =
@@ -1938,6 +1942,9 @@ virNWFilterDHCPSnoopEnd(const char *ifname)
 void
 virNWFilterDHCPSnoopShutdown(void)
 {
+    if (!virNWFilterSnoopState.snoopReqs)
+        return;
+
     virNWFilterSnoopEndThreads();
     virNWFilterSnoopJoinThreads();
 
@@ -1947,9 +1954,13 @@ virNWFilterDHCPSnoopShutdown(void)
         g_clear_pointer(&virNWFilterSnoopState.snoopReqs, g_hash_table_unref);
     }
 
+    virMutexDestroy(&virNWFilterSnoopState.snoopLock);
+
     VIR_WITH_MUTEX_LOCK_GUARD(&virNWFilterSnoopState.activeLock) {
         g_clear_pointer(&virNWFilterSnoopState.active, g_hash_table_unref);
     }
+
+    virMutexDestroy(&virNWFilterSnoopState.activeLock);
 }
 
 #else /* WITH_LIBPCAP */
-- 
2.31.1