diff options
| author | Eric Dumazet <edumazet@google.com> | 2015-11-09 17:51:23 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-12-09 13:42:54 -0500 |
| commit | dfc91042ce263ee530897d47cd84fb8146b308dc (patch) | |
| tree | 9609980fb52a5bbc8e0c8875faecfc91f4bc665c | |
| parent | 02126db35a1f29df1562ab9d22257d80526ba8de (diff) | |
| download | lwn-dfc91042ce263ee530897d47cd84fb8146b308dc.tar.gz lwn-dfc91042ce263ee530897d47cd84fb8146b308dc.zip | |
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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -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); } } |