[libvirt] [PATCH] Check for existence of interface prior to setting terminate flag

[John Ferlan]

https://bugzilla.redhat.com/show_bug.cgi?id=903480

During domain destruction it's possible that the learnIPAddressThread has
already removed the interface prior to the teardown filter path being run.
The teardown code would only be telling the thread to terminate.
---
 src/nwfilter/nwfilter_learnipaddr.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/nwfilter/nwfilter_learnipaddr.c b/src/nwfilter/nwfilter_learnipaddr.c
index 2b49333..c56d119 100644
--- a/src/nwfilter/nwfilter_learnipaddr.c
+++ b/src/nwfilter/nwfilter_learnipaddr.c
@@ -251,6 +251,14 @@ virNWFilterTerminateLearnReq(const char *ifname) {
     int ifindex;
     virNWFilterIPAddrLearnReqPtr req;
 
+    /* It's possible that it's already be removed as a result of
+     * virNWFilterDeregisterLearnReq during learnIPAddressThread() exit
+     */
+    if (virNetDevExists(ifname) != 1) {
+        virResetLastError();
+        return 0;
+    }
+
     if (virNetDevGetIndex(ifname, &ifindex) < 0) {
         virResetLastError();
         return rc;
-- 
1.8.1.4