diff options
author | Eric Dumazet <edumazet@google.com> | 2015-11-09 17:51:23 -0800 |
---|---|---|
committer | Jiri Slaby <jslaby@suse.cz> | 2015-11-14 17:29:48 +0100 |
commit | e98b2397a2181f4d066342beb6a220e43c404e44 (patch) | |
tree | 03f1ca775e97329d8c581c5e2555ebefcaab5d4d | |
parent | 6651ab3cd17428ac02a53a2f0e90f089a203f03c (diff) |
net: fix a race in dst_release()
[ Upstream commit d69bbf88c8d0b367cf3e3a052f6daadf630ee566 ]
Only cpu seeing dst refcount going to 0 can safely
dereference dst->flags.
Otherwise an other cpu might already have freed the dst.
Fixes: 27b75c95f10d ("net: avoid RCU for NOCACHE dst")
Reported-by: Greg Thelen <gthelen@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
-rw-r--r-- | net/core/dst.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/net/core/dst.c b/net/core/dst.c index 15b6792e6ebb..c07070544e3f 100644 --- a/net/core/dst.c +++ b/net/core/dst.c @@ -283,7 +283,7 @@ void dst_release(struct dst_entry *dst) newrefcnt = atomic_dec_return(&dst->__refcnt); WARN_ON(newrefcnt < 0); - if (unlikely(dst->flags & DST_NOCACHE) && !newrefcnt) + if (!newrefcnt && unlikely(dst->flags & DST_NOCACHE)) call_rcu(&dst->rcu_head, dst_destroy_rcu); } } |