| Message ID | 1318926762-14563-1-git-send-email-roy.qing.li@gmail.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
Le mardi 18 octobre 2011 à 16:32 +0800, roy.qing.li@gmail.com a écrit : > when use dst_get_neighbour to get neighbour, we need > rcu_read_lock to protect, since dst_get_neighbour uses > rcu_dereference. > > The bug was reported by Ari Savolainen <ari.m.savolainen@gmail.com> > ... > > Reported-by: Ari Savolainen <ari.m.savolainen@gmail.com> > Signed-off-by: RongQing <roy.qing.li@gmail.com> Acked-by: Eric Dumazet <eric.dumazet@gmail.com> -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
From: Eric Dumazet <eric.dumazet@gmail.com> Date: Tue, 18 Oct 2011 11:11:35 +0200 > Le mardi 18 octobre 2011 à 16:32 +0800, roy.qing.li@gmail.com a écrit : >> when use dst_get_neighbour to get neighbour, we need >> rcu_read_lock to protect, since dst_get_neighbour uses >> rcu_dereference. >> >> The bug was reported by Ari Savolainen <ari.m.savolainen@gmail.com> >> > ... >> >> Reported-by: Ari Savolainen <ari.m.savolainen@gmail.com> >> Signed-off-by: RongQing <roy.qing.li@gmail.com> > > Acked-by: Eric Dumazet <eric.dumazet@gmail.com> Applied, thanks. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/net/core/neighbour.c b/net/core/neighbour.c index 4344964..909ecb3 100644 --- a/net/core/neighbour.c +++ b/net/core/neighbour.c @@ -1168,10 +1168,14 @@ int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new, struct dst_entry *dst = skb_dst(skb); struct neighbour *n2, *n1 = neigh; write_unlock_bh(&neigh->lock); + + rcu_read_lock(); /* On shaper/eql skb->dst->neighbour != neigh :( */ if (dst && (n2 = dst_get_neighbour(dst)) != NULL) n1 = n2; n1->output(n1, skb); + rcu_read_unlock(); + write_lock_bh(&neigh->lock); } skb_queue_purge(&neigh->arp_queue);
when use dst_get_neighbour to get neighbour, we need rcu_read_lock to protect, since dst_get_neighbour uses rcu_dereference. The bug was reported by Ari Savolainen <ari.m.savolainen@gmail.com> [ 105.612095] [ 105.612096] =================================================== [ 105.612100] [ INFO: suspicious rcu_dereference_check() usage. ] [ 105.612101] --------------------------------------------------- [ 105.612103] include/net/dst.h:91 invoked rcu_dereference_check() without protection! [ 105.612105] [ 105.612106] other info that might help us debug this: [ 105.612106] [ 105.612108] [ 105.612108] rcu_scheduler_active = 1, debug_locks = 0 [ 105.612110] 1 lock held by dnsmasq/2618: [ 105.612111] #0: (rtnl_mutex){+.+.+.}, at: [<ffffffff815df8c7>] rtnl_lock+0x17/0x20 [ 105.612120] [ 105.612121] stack backtrace: [ 105.612123] Pid: 2618, comm: dnsmasq Not tainted 3.1.0-rc1 #41 [ 105.612125] Call Trace: [ 105.612129] [<ffffffff810ccdcb>] lockdep_rcu_dereference+0xbb/0xc0 [ 105.612132] [<ffffffff815dc5a9>] neigh_update+0x4f9/0x5f0 [ 105.612135] [<ffffffff815da001>] ? neigh_lookup+0xe1/0x220 [ 105.612139] [<ffffffff81639298>] arp_req_set+0xb8/0x230 [ 105.612142] [<ffffffff8163a59f>] arp_ioctl+0x1bf/0x310 [ 105.612146] [<ffffffff810baa40>] ? lock_hrtimer_base.isra.26+0x30/0x60 [ 105.612150] [<ffffffff8163fb75>] inet_ioctl+0x85/0x90 [ 105.612154] [<ffffffff815b5520>] sock_do_ioctl+0x30/0x70 [ 105.612157] [<ffffffff815b55d3>] sock_ioctl+0x73/0x280 [ 105.612162] [<ffffffff811b7698>] do_vfs_ioctl+0x98/0x570 [ 105.612165] [<ffffffff811a5c40>] ? fget_light+0x340/0x3a0 [ 105.612168] [<ffffffff811b7bbf>] sys_ioctl+0x4f/0x80 [ 105.612172] [<ffffffff816fdcab>] system_call_fastpath+0x16/0x1b Reported-by: Ari Savolainen <ari.m.savolainen@gmail.com> Signed-off-by: RongQing <roy.qing.li@gmail.com> --- net/core/neighbour.c | 4 ++++ 1 files changed, 4 insertions(+), 0 deletions(-)