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| author | Eric Dumazet <edumazet@google.com> | 2015-11-09 17:51:23 -0800 |
|---|---|---|
| committer | Sasha Levin <sasha.levin@oracle.com> | 2015-12-03 10:17:37 -0500 |
| commit | 5bac169bb395d81ea3e7e824cb7b9682166ab991 (patch) | |
| tree | 1c6c9dddd33e440fd23da2dd21e939e9e4ef0148 | |
| parent | b2567c1c3e78d35dab01ac1f3f8331d42d3df062 (diff) | |
| download | lwn-5bac169bb395d81ea3e7e824cb7b9682166ab991.tar.gz lwn-5bac169bb395d81ea3e7e824cb7b9682166ab991.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: Sasha Levin <sasha.levin@oracle.com>
| -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 a028409ee438..a80e92346b9b 100644 --- a/net/core/dst.c +++ b/net/core/dst.c @@ -285,7 +285,7 @@ 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); } } |