diff options
| author | Eric Dumazet <edumazet@google.com> | 2015-11-09 17:51:23 -0800 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2015-11-27 12:48:24 +0000 |
| commit | 1a513170dd8f7a56dcabc879a2ce235131d99225 (patch) | |
| tree | 02a2f498c3980ddb0fe9b14815cee5744e2bd31b /net | |
| parent | 7abbc81bd03cd019f4d59bfba291d965acc5b5f0 (diff) | |
net: fix a race in dst_release()
commit d69bbf88c8d0b367cf3e3a052f6daadf630ee566 upstream.
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>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'net')
| -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 d5e2c4c09107..946e214787c6 100644 --- a/net/core/dst.c +++ b/net/core/dst.c @@ -272,7 +272,7 @@ 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)) { dst = dst_destroy(dst); if (dst) __dst_free(dst); |