[PATCH net-2.6] net/sched: fix missing spinlock init

[PATCH net-2.6] net/sched: fix missing spinlock init

[Eric Dumazet]

Under network load, doing :

tc qdisc del dev eth0 root

triggers :

[  167.193087] BUG: spinlock bad magic on CPU#3, udpflood/4928
[  167.193139]  lock: c15bc324, .magic: 00000000, .owner:
<none>/-1, .owner_cpu: -1
[  167.193193] Pid: 4928, comm: udpflood Not tainted
2.6.36-rc7-11417-g215340c-dirty #323
[  167.193245] Call Trace:
[  167.193292]  [<c13abaa0>] ? printk+0x18/0x20
[  167.193342]  [<c11afb53>] spin_bug+0xa3/0xf0
[  167.193389]  [<c11afcdd>] do_raw_spin_lock+0x7d/0x160
[  167.193440]  [<c1313d4e>] ? __dev_xmit_skb+0x27e/0x2b0
[  167.193496]  [<c107382b>] ? trace_hardirqs_on+0xb/0x10
[  167.193545]  [<c13ae99a>] _raw_spin_lock+0x3a/0x40
[  167.193593]  [<c1313d4e>] ? __dev_xmit_skb+0x27e/0x2b0
[  167.193641]  [<c1313d4e>] __dev_xmit_skb+0x27e/0x2b0

commit 79640a4ca695 (add additional lock to qdisc to increase
throughput) forgot to initialize  noop_qdisc and noqueue_qdisc busylock 

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
---
 net/sched/sch_generic.c |    2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 3d57681..0abcc49 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -383,6 +383,7 @@ struct Qdisc noop_qdisc = {
 	.list		=	LIST_HEAD_INIT(noop_qdisc.list),
 	.q.lock		=	__SPIN_LOCK_UNLOCKED(noop_qdisc.q.lock),
 	.dev_queue	=	&noop_netdev_queue,
+	.busylock	=	__SPIN_LOCK_UNLOCKED(noop_qdisc.busylock),
 };
 EXPORT_SYMBOL(noop_qdisc);
 
@@ -409,6 +410,7 @@ static struct Qdisc noqueue_qdisc = {
 	.list		=	LIST_HEAD_INIT(noqueue_qdisc.list),
 	.q.lock		=	__SPIN_LOCK_UNLOCKED(noqueue_qdisc.q.lock),
 	.dev_queue	=	&noqueue_netdev_queue,
+	.busylock	=	__SPIN_LOCK_UNLOCKED(noqueue_qdisc.busylock),
 };
 
 

Re: [PATCH net-2.6] net/sched: fix missing spinlock init

[David Miller]

From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Sat, 16 Oct 2010 07:22:34 +0200

> Under network load, doing :
> 
> tc qdisc del dev eth0 root
> 
> triggers :
 ...
> commit 79640a4ca695 (add additional lock to qdisc to increase
> throughput) forgot to initialize  noop_qdisc and noqueue_qdisc busylock 
> 
> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
> ---

Applied.