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| author | Jamal Hadi Salim <hadi@cyberus.ca> | 2007-09-12 16:32:59 +0200 |
|---|---|---|
| committer | David S. Miller <davem@sunset.davemloft.net> | 2007-09-14 16:43:05 -0700 |
| commit | e1e992e52faa588667e1378a2573b4b8e3fa6670 (patch) | |
| tree | 771f664db9e2d7119dfea92a117deeb89e7b55e5 /net/sched/act_police.c | |
| parent | 4878809f711981a602cc562eb47994fc81ea0155 (diff) | |
| download | lwn-e1e992e52faa588667e1378a2573b4b8e3fa6670.tar.gz lwn-e1e992e52faa588667e1378a2573b4b8e3fa6670.zip | |
[NET_SCHED] protect action config/dump from irqs
(with no apologies to C Heston)
On Mon, 2007-10-09 at 21:00 +0800, Herbert Xu wrote:
On Sun, Sep 02, 2007 at 01:11:29PM +0000, Christian Kujau wrote:
> >
> > after upgrading to 2.6.23-rc5 (and applying davem's fix [0]), lockdep
> > was quite noisy when I tried to shape my external (wireless) interface:
> >
> > [ 6400.534545] FahCore_78.exe/3552 just changed the state of lock:
> > [ 6400.534713] (&dev->ingress_lock){-+..}, at: [<c038d595>]
> > netif_receive_skb+0x2d5/0x3c0
> > [ 6400.534941] but this lock took another, soft-read-irq-unsafe lock in the
> > past:
> > [ 6400.535145] (police_lock){-.--}
>
> This is a genuine dead-lock. The police lock can be taken
> for reading with softirqs on. If a second CPU tries to take
> the police lock for writing, while holding the ingress lock,
> then a softirq on the first CPU can dead-lock when it tries
> to get the ingress lock.
Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sched/act_police.c')
| -rw-r--r-- | net/sched/act_police.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/net/sched/act_police.c b/net/sched/act_police.c index 6085be578459..17f6f27e28a2 100644 --- a/net/sched/act_police.c +++ b/net/sched/act_police.c @@ -56,7 +56,7 @@ static int tcf_act_police_walker(struct sk_buff *skb, struct netlink_callback *c int err = 0, index = -1, i = 0, s_i = 0, n_i = 0; struct rtattr *r; - read_lock(&police_lock); + read_lock_bh(&police_lock); s_i = cb->args[0]; @@ -85,7 +85,7 @@ static int tcf_act_police_walker(struct sk_buff *skb, struct netlink_callback *c } } done: - read_unlock(&police_lock); + read_unlock_bh(&police_lock); if (n_i) cb->args[0] += n_i; return n_i; |