From mboxrd@z Thu Jan 1 00:00:00 1970 From: jamal Subject: Re: 2.6.23-rc5: possible irq lock inversion dependency detected Date: Tue, 11 Sep 2007 08:01:46 -0400 Message-ID: <1189512106.4231.6.camel@localhost> References: <20070910130024.GA27939@gondor.apana.org.au> <1189469081.14002.3.camel@localhost> <20070911021812.GA1544@gondor.apana.org.au> Reply-To: hadi@cyberus.ca Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="=-Qkdn9XYEaPjByoZ+fQ1E" Cc: Christian Kujau , linux-kernel@vger.kernel.org, netdev@vger.kernel.org To: Herbert Xu Return-path: Received: from wx-out-0506.google.com ([66.249.82.230]:24938 "EHLO wx-out-0506.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757526AbXIKMBu (ORCPT ); Tue, 11 Sep 2007 08:01:50 -0400 Received: by wx-out-0506.google.com with SMTP id h31so1420845wxd for ; Tue, 11 Sep 2007 05:01:49 -0700 (PDT) In-Reply-To: <20070911021812.GA1544@gondor.apana.org.au> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org --=-Qkdn9XYEaPjByoZ+fQ1E Content-Type: text/plain Content-Transfer-Encoding: 7bit On Tue, 2007-11-09 at 10:18 +0800, Herbert Xu wrote: > Jamal, it's the police_lock that we need to make _bh. The > ingress_lock is already _bh because of the spin_lock_bh that > directly precedes it. > > Oh and I think the same thing applies for the other actions > too. ga-Dang. Ok, here it is. If you see(?) any more farts let me know. I am around for another 30 minutes and off for about 18 hours. Christian, i took your config and qos setup but I cant reproduce the issue - i think i may need some of that wireless setup to recreate. So if you can test this and validate it works we can push it forward. cheers, jamal --=-Qkdn9XYEaPjByoZ+fQ1E Content-Disposition: attachment; filename=act_bhl Content-Type: text/plain; name=act_bhl; charset=us-ascii Content-Transfer-Encoding: 7bit [NET_SCHED] protect action config/dump from irqs >>From the sharp laser eyes of Herbert Xu to my slow farting brain... (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 --- a/net/sched/act_police.c 2007/09/11 10:39:36 1.1 +++ b/net/sched/act_police.c 2007/09/11 10:51:47 @@ -56,7 +56,7 @@ 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 @@ } } done: - read_unlock(&police_lock); + read_unlock_bh(&police_lock); if (n_i) cb->args[0] += n_i; return n_i; --- a/net/sched/act_api.c 2007/09/11 10:47:51 1.1 +++ b/net/sched/act_api.c 2007/09/11 10:50:47 @@ -68,7 +68,7 @@ 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 @@ } } 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 *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; } --=-Qkdn9XYEaPjByoZ+fQ1E--