This is a note to let you know that I've just added the patch titled
packet: read num_members once in packet_rcv_fanout()
to the 4.0-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
packet-read-num_members-once-in-packet_rcv_fanout.patch
and it can be found in the queue-4.0 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Fri Jul 3 19:59:52 PDT 2015
From: Eric Dumazet <edumazet@xxxxxxxxxx>
Date: Tue, 16 Jun 2015 07:59:11 -0700
Subject: packet: read num_members once in packet_rcv_fanout()
From: Eric Dumazet <edumazet@xxxxxxxxxx>
[ 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@xxxxxxxxxx>
Cc: Willem de Bruijn <willemb@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/packet/af_packet.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -1347,7 +1347,7 @@ static int packet_rcv_fanout(struct sk_b
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;
Patches currently in stable-queue which might be from edumazet@xxxxxxxxxx are
queue-4.0/packet-avoid-out-of-bounds-read-in-round-robin-fanout.patch
queue-4.0/net-don-t-wait-for-order-3-page-allocation.patch
queue-4.0/tcp-do-not-call-tcp_fastopen_reset_cipher-from-interrupt-context.patch
queue-4.0/packet-read-num_members-once-in-packet_rcv_fanout.patch
queue-4.0/neigh-do-not-modify-unlinked-entries.patch
queue-4.0/bnx2x-fix-lockdep-splat.patch
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