diff options
| author | Eric Dumazet <edumazet@google.com> | 2015-06-16 07:59:11 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-07-10 09:49:28 -0700 |
| commit | d7884e43677ba8618ae2f1ead7b96b215b409e20 (patch) | |
| tree | 3c9261f8eaeec04a00cfc7ca8a6e15aaf19ff5ed /net/packet | |
| parent | 08be544ef5d8453b7778bd57f3da8eeebcf1cd65 (diff) | |
packet: read num_members once in packet_rcv_fanout()
[ Upstream commit f98f4514d07871da7a113dd9e3e330743fd70ae4 ]
We need to tell compiler it must not read f->num_members multiple
times. Otherwise testing if num is not zero is flaky, and we could
attempt an invalid divide by 0 in fanout_demux_cpu()
Note bug was present in packet_rcv_fanout_hash() and
packet_rcv_fanout_lb() but final 3.1 had a simple location
after commit 95ec3eb417115fb ("packet: Add 'cpu' fanout policy.")
Fixes: dc99f600698dc ("packet: Add fanout support.")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net/packet')
| -rw-r--r-- | net/packet/af_packet.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index b5989c6ee551..131545a06f05 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -1353,7 +1353,7 @@ static int packet_rcv_fanout(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev) { struct packet_fanout *f = pt->af_packet_priv; - unsigned int num = f->num_members; + unsigned int num = READ_ONCE(f->num_members); struct packet_sock *po; unsigned int idx; |