From e1e992e52faa588667e1378a2573b4b8e3fa6670 Mon Sep 17 00:00:00 2001 From: Jamal Hadi Salim Date: Wed, 12 Sep 2007 16:32:59 +0200 Subject: [PATCH] [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: [] > > 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 Acked-by: Herbert Xu Signed-off-by: David S. Miller --- net/sched/act_api.c | 8 ++++---- net/sched/act_police.c | 4 ++-- 2 files changed, 6 insertions(+), 6 deletions(-) diff --git a/net/sched/act_api.c b/net/sched/act_api.c index feef366cad5d..72cdb0fade20 100644 --- a/net/sched/act_api.c +++ b/net/sched/act_api.c @@ -68,7 +68,7 @@ static int tcf_dump_walker(struct sk_buff *skb, struct netlink_callback *cb, int err = 0, index = -1,i = 0, s_i = 0, n_i = 0; struct rtattr *r ; - read_lock(hinfo->lock); + read_lock_bh(hinfo->lock); s_i = cb->args[0]; @@ -96,7 +96,7 @@ static int tcf_dump_walker(struct sk_buff *skb, struct netlink_callback *cb, } } done: - read_unlock(hinfo->lock); + read_unlock_bh(hinfo->lock); if (n_i) cb->args[0] += n_i; return n_i; @@ -156,13 +156,13 @@ struct tcf_common *tcf_hash_lookup(u32 index, struct tcf_hashinfo *hinfo) { struct tcf_common *p; - read_lock(hinfo->lock); + read_lock_bh(hinfo->lock); for (p = hinfo->htab[tcf_hash(index, hinfo->hmask)]; p; p = p->tcfc_next) { if (p->tcfc_index == index) break; } - read_unlock(hinfo->lock); + read_unlock_bh(hinfo->lock); return p; } 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;