From: Stefan Berger <stefanb(a)linux.vnet.ibm.com&gt; https://bugzilla.redhat.com/show_bug.cgi?id=1071181 Commit 49b59a15 fixed one problem but masks another one related to pointer freeing. Use virAtomicIntGet() to test for 0 rather than trying to test for 'true' after virAtomicIntDecAndTest(). Avoid putting of the virNWFilterSnoopReq once the thread has been started. Signed-off-by: Stefan Berger <stefanb(a)linux.vnet.ibm.com&gt; --- src/nwfilter/nwfilter_dhcpsnoop.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/src/nwfilter/nwfilter_dhcpsnoop.c b/src/nwfilter/nwfilter_dhcpsnoop.c index d2a8062..32ca304 100644 --- a/src/nwfilter/nwfilter_dhcpsnoop.c +++ b/src/nwfilter/nwfilter_dhcpsnoop.c @@ -720,7 +720,10 @@ virNWFilterSnoopReqPut(virNWFilterSnoopReqPtr req) virNWFilterSnoopLock(); - if (virAtomicIntDecAndTest(&req->refctr)) { + virAtomicIntDecAndTest(&req->refctr); + + /* make sure it's 0; virAtomitIntDecAndTest may return true on '1' */ + if (virAtomicIntGet(&req->refctr) == 0) { /* * delete the request: * - if we don't find req on the global list anymore @@ -1605,6 +1608,7 @@ virNWFilterDHCPSnoopReq(virNWFilterTechDriverPtr techdriver, int tmp; virThread thread; virNWFilterVarValuePtr dhcpsrvrs; + bool threadPuts = false; virNWFilterSnoopIFKeyFMT(ifkey, vmuuid, macaddr); @@ -1690,6 +1694,8 @@ virNWFilterDHCPSnoopReq(virNWFilterTechDriverPtr techdriver, /* prevent thread from holding req */ virNWFilterSnoopReqLock(req); + threadPuts = true; + if (virThreadCreate(&thread, false, virNWFilterDHCPSnoopThread, req) != 0) { virReportError(VIR_ERR_INTERNAL_ERROR, @@ -1737,7 +1743,8 @@ exit_rem_ifnametokey: exit_snoopunlock: virNWFilterSnoopUnlock(); exit_snoopreqput: - virNWFilterSnoopReqPut(req); + if (!threadPuts) + virNWFilterSnoopReqPut(req); return -1; } -- 1.8.1.4