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authorJamal Hadi Salim <hadi@cyberus.ca>2007-09-12 10:32:59 -0400
committerDavid S. Miller <davem@sunset.davemloft.net>2007-09-14 19:43:05 -0400
commite1e992e52faa588667e1378a2573b4b8e3fa6670 (patch)
tree771f664db9e2d7119dfea92a117deeb89e7b55e5 /net/sched/act_api.c
parent4878809f711981a602cc562eb47994fc81ea0155 (diff)
[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_api.c')
-rw-r--r--net/sched/act_api.c8
1 files changed, 4 insertions, 4 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,
68 int err = 0, index = -1,i = 0, s_i = 0, n_i = 0; 68 int err = 0, index = -1,i = 0, s_i = 0, n_i = 0;
69 struct rtattr *r ; 69 struct rtattr *r ;
70 70
71 read_lock(hinfo->lock); 71 read_lock_bh(hinfo->lock);
72 72
73 s_i = cb->args[0]; 73 s_i = cb->args[0];
74 74
@@ -96,7 +96,7 @@ static int tcf_dump_walker(struct sk_buff *skb, struct netlink_callback *cb,
96 } 96 }
97 } 97 }
98done: 98done:
99 read_unlock(hinfo->lock); 99 read_unlock_bh(hinfo->lock);
100 if (n_i) 100 if (n_i)
101 cb->args[0] += n_i; 101 cb->args[0] += n_i;
102 return n_i; 102 return n_i;
@@ -156,13 +156,13 @@ struct tcf_common *tcf_hash_lookup(u32 index, struct tcf_hashinfo *hinfo)
156{ 156{
157 struct tcf_common *p; 157 struct tcf_common *p;
158 158
159 read_lock(hinfo->lock); 159 read_lock_bh(hinfo->lock);
160 for (p = hinfo->htab[tcf_hash(index, hinfo->hmask)]; p; 160 for (p = hinfo->htab[tcf_hash(index, hinfo->hmask)]; p;
161 p = p->tcfc_next) { 161 p = p->tcfc_next) {
162 if (p->tcfc_index == index) 162 if (p->tcfc_index == index)
163 break; 163 break;
164 } 164 }
165 read_unlock(hinfo->lock); 165 read_unlock_bh(hinfo->lock);
166 166
167 return p; 167 return p;
168} 168}