2008-06-07 01:23:30

by Chris Wright

[permalink] [raw]
Subject: [patch 39/50] netfilter: nf_conntrack_ipv6: fix inconsistent lock state in nf_ct_frag6_gather()

-stable review patch. If anyone has any objections, please let us know.
---------------------

From: Patrick McHardy <[email protected]>

upstream commit: b9c698964614f71b9c8afeca163a945b4c2e2d20

[ 63.531438] =================================
[ 63.531520] [ INFO: inconsistent lock state ]
[ 63.531520] 2.6.26-rc4 #7
[ 63.531520] ---------------------------------
[ 63.531520] inconsistent {softirq-on-W} -> {in-softirq-W} usage.
[ 63.531520] tcpsic6/3864 [HC0[0]:SC1[1]:HE1:SE0] takes:
[ 63.531520] (&q->lock#2){-+..}, at: [<c07175b0>] ipv6_frag_rcv+0xd0/0xbd0
[ 63.531520] {softirq-on-W} state was registered at:
[ 63.531520] [<c0143bba>] __lock_acquire+0x3aa/0x1080
[ 63.531520] [<c0144906>] lock_acquire+0x76/0xa0
[ 63.531520] [<c07a8f0b>] _spin_lock+0x2b/0x40
[ 63.531520] [<c0727636>] nf_ct_frag6_gather+0x3f6/0x910
...

According to this and another similar lockdep report inet_fragment
locks are taken from nf_ct_frag6_gather() with softirqs enabled, but
these locks are mainly used in softirq context, so disabling BHs is
necessary.

Reported-and-tested-by: Eric Sesterhenn <[email protected]>
Signed-off-by: Jarek Poplawski <[email protected]>
Signed-off-by: Patrick McHardy <[email protected]>
Signed-off-by: Chris Wright <[email protected]>
---

net/ipv6/netfilter/nf_conntrack_reasm.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

--- a/net/ipv6/netfilter/nf_conntrack_reasm.c
+++ b/net/ipv6/netfilter/nf_conntrack_reasm.c
@@ -209,7 +209,9 @@ fq_find(__be32 id, struct in6_addr *src,
arg.dst = dst;
hash = ip6qhashfn(id, src, dst);

+ local_bh_disable();
q = inet_frag_find(&nf_init_frags, &nf_frags, &arg, hash);
+ local_bh_enable();
if (q == NULL)
goto oom;

@@ -638,10 +640,10 @@ struct sk_buff *nf_ct_frag6_gather(struc
goto ret_orig;
}

- spin_lock(&fq->q.lock);
+ spin_lock_bh(&fq->q.lock);

if (nf_ct_frag6_queue(fq, clone, fhdr, nhoff) < 0) {
- spin_unlock(&fq->q.lock);
+ spin_unlock_bh(&fq->q.lock);
pr_debug("Can't insert skb to queue\n");
fq_put(fq);
goto ret_orig;
@@ -652,7 +654,7 @@ struct sk_buff *nf_ct_frag6_gather(struc
if (ret_skb == NULL)
pr_debug("Can't reassemble fragmented packets\n");
}
- spin_unlock(&fq->q.lock);
+ spin_unlock_bh(&fq->q.lock);

fq_put(fq);
return ret_skb;

--