svn commit: r287543 - head/sys/dev/netmap
Adrian Chadd
adrian at FreeBSD.org
Mon Sep 7 23:16:40 UTC 2015
Author: adrian
Date: Mon Sep 7 23:16:39 2015
New Revision: 287543
URL: https://svnweb.freebsd.org/changeset/base/287543
Log:
Don't call enable_all_rings if the adapter has been freed.
This is a subtle use-after-free race that results in some very undesirable
hang behaviour.
Reviewed by: pkelsey
Obtained from: Kip Macy, NextBSD (https://github.com/NextBSD/NextBSD/commit/91a9bd1dbb33dafb41684d054e59d73976de9654)
Modified:
head/sys/dev/netmap/netmap.c
Modified: head/sys/dev/netmap/netmap.c
==============================================================================
--- head/sys/dev/netmap/netmap.c Mon Sep 7 21:59:11 2015 (r287542)
+++ head/sys/dev/netmap/netmap.c Mon Sep 7 23:16:39 2015 (r287543)
@@ -2841,10 +2841,12 @@ void
netmap_detach(struct ifnet *ifp)
{
struct netmap_adapter *na = NA(ifp);
+ int skip;
if (!na)
return;
+ skip = 0;
NMG_LOCK();
netmap_disable_all_rings(ifp);
na->ifp = NULL;
@@ -2856,10 +2858,11 @@ netmap_detach(struct ifnet *ifp)
* the driver is gone.
*/
if (na->na_flags & NAF_NATIVE) {
- netmap_adapter_put(na);
+ skip = netmap_adapter_put(na);
}
/* give them a chance to notice */
- netmap_enable_all_rings(ifp);
+ if (skip == 0)
+ netmap_enable_all_rings(ifp);
NMG_UNLOCK();
}
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