Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759257AbZFQKTE (ORCPT ); Wed, 17 Jun 2009 06:19:04 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757071AbZFQKSv (ORCPT ); Wed, 17 Jun 2009 06:18:51 -0400 Received: from gw1.cosmosbay.com ([212.99.114.194]:35971 "EHLO gw1.cosmosbay.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756877AbZFQKSu (ORCPT ); Wed, 17 Jun 2009 06:18:50 -0400 Message-ID: <4A38C2F3.3000009@gmail.com> Date: Wed, 17 Jun 2009 12:18:27 +0200 From: Eric Dumazet User-Agent: Thunderbird 2.0.0.21 (Windows/20090302) MIME-Version: 1.0 To: Ingo Molnar CC: David Miller , Thomas Gleixner , torvalds@linux-foundation.org, akpm@linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Patrick McHardy Subject: Re: [bug] __nf_ct_refresh_acct(): WARNING: at lib/list_debug.c:30 __list_add+0x7d/0xad() References: <20090615.050449.144947903.davem@davemloft.net> <20090616091538.GA4184@elte.hu> <20090616.034752.226811527.davem@davemloft.net> <20090616105304.GA3579@elte.hu> <20090616122415.GA16630@elte.hu> <20090617092152.GA17449@elte.hu> In-Reply-To: <20090617092152.GA17449@elte.hu> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-1.6 (gw1.cosmosbay.com [0.0.0.0]); Wed, 17 Jun 2009 12:18:30 +0200 (CEST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7488 Lines: 160 Ingo Molnar a ?crit : > here's another bug i triggered today - some sort of memory/list > corruption going on in the timer code. Then i turned on debugobjects > and got a pretty specific assert in the TCP code: > > [ 48.320340] ------------[ cut here ]------------ > [ 48.324031] WARNING: at lib/list_debug.c:30 __list_add+0x7d/0xad() > [ 48.324031] Hardware name: System Product Name > [ 48.324031] list_add corruption. prev->next should be next (ffffffff81fe2280), but was ffff88003f901440. (prev=ffff880002a9bcf0). > [ 48.324031] Modules linked in: > [ 48.324031] Pid: 0, comm: swapper Tainted: G W 2.6.30-tip #54394 > [ 48.324031] Call Trace: > [ 48.324031] [] ? __list_add+0x7d/0xad > [ 48.324031] [] warn_slowpath_common+0x8d/0xd0 > [ 48.324031] [] warn_slowpath_fmt+0x50/0x66 > [ 48.324031] [] __list_add+0x7d/0xad > [ 48.324031] [] internal_add_timer+0xd1/0xe7 > [ 48.324031] [] __mod_timer+0x107/0x139 > [ 48.324031] [] mod_timer_pending+0x28/0x3e > [ 48.324031] [] __nf_ct_refresh_acct+0x71/0xf9 > [ 48.324031] [] tcp_packet+0x60c/0x6a2 > [ 48.324031] [] ? nf_conntrack_find_get+0xb7/0xef > [ 48.324031] [] ? nf_conntrack_find_get+0x0/0xef > [ 48.324031] [] nf_conntrack_in+0x3a3/0x534 > [ 48.324031] [] ? ip_rcv_finish+0x0/0x3bc > [ 48.324031] [] ipv4_conntrack_in+0x34/0x4a > [ 48.324031] [] nf_iterate+0x5d/0xb1 > [ 48.324031] [] ? ftrace_call+0x5/0x2b > [ 48.324031] [] ? ip_rcv_finish+0x0/0x3bc > [ 48.324031] [] nf_hook_slow+0xa4/0x133 > [ 48.324031] [] ? ip_rcv_finish+0x0/0x3bc > [ 48.324031] [] ip_rcv+0x2ae/0x30d > [ 48.324031] [] ? netpoll_rx+0x14/0x9d > [ 48.324031] [] netif_receive_skb+0x3b1/0x402 > [ 48.324031] [] ? netif_receive_skb+0x17b/0x402 > [ 48.324031] [] ? skb_pull+0xd/0x59 > [ 48.324031] [] ? eth_type_trans+0x48/0x104 > [ 48.324031] [] nv_rx_process_optimized+0x15a/0x227 > [ 48.324031] [] nv_napi_poll+0x2a9/0x2cd > [ 48.324031] [] net_rx_action+0xd1/0x249 > [ 48.324031] [] ? net_rx_action+0x1e8/0x249 > [ 48.324031] [] __do_softirq+0xcb/0x1bb > [ 48.324031] [] call_softirq+0x1c/0x30 > [ 48.324031] [] do_softirq+0x5f/0xd7 > [ 48.324031] [] irq_exit+0x66/0xb9 > [ 48.324031] [] do_IRQ+0xbb/0xe8 > [ 48.324031] [] ? early_idt_handler+0x0/0x71 > [ 48.324031] [] ret_from_intr+0x0/0x16 > [ 48.324031] [] ? default_idle+0x59/0x9d > [ 48.324031] [] ? trace_hardirqs_on+0x20/0x36 > [ 48.324031] [] ? native_safe_halt+0xb/0xd > [ 48.324031] [] ? native_safe_halt+0x9/0xd > [ 48.324031] [] ? default_idle+0x5e/0x9d > [ 48.324031] [] ? stop_critical_timings+0x3d/0x54 > [ 48.324031] [] ? cpu_idle+0xbe/0x107 > [ 48.324031] [] ? early_idt_handler+0x0/0x71 > [ 48.324031] [] ? rest_init+0x79/0x8f > [ 48.324031] [] ? early_idt_handler+0x0/0x71 > [ 48.324031] [] ? start_kernel+0x2d8/0x2f3 > [ 48.324031] [] ? early_idt_handler+0x0/0x71 > [ 48.324031] [] ? x86_64_start_reservations+0x8f/0xaa > [ 48.324031] [] ? __init_begin+0x0/0x140 > [ 48.324031] [] ? x86_64_start_kernel+0x104/0x127 > [ 48.324031] ---[ end trace 5a5d197966b56a31 ]--- > modprobe: FATAL: Could not load /lib/modules/2.6.30-tip/modules.dep: No such file or directory > > this too is a new pattern. Config and full bootlog attached. > > Unfortunately it's not clearly reproducible - needs some networking > load to trigger, and sometimes the symptoms are just a straight hang > (with no console messages) - so not very bisection friendly. > > Ingo > commit 65cb9fda32be613216f601a330b311c3bd7a8436 seems the origin... (and/or 440f0d588555892601cfe511728a0fc0c8204063) commit 65cb9fda32be613216f601a330b311c3bd7a8436 Author: Patrick McHardy Date: Sat Jun 13 12:21:49 2009 +0200 netfilter: nf_conntrack: use mod_timer_pending() for conntrack refresh Use mod_timer_pending() instead of atomic sequence of del_timer()/ add_timer(). mod_timer_pending() does not rearm an inactive timer, so we don't need the conntrack lock anymore to make sure we don't accidentally rearm a timer of a conntrack which is in the process of being destroyed. With this change, we don't need to take the global lock anymore at all, counter updates can be performed under the per-conntrack lock. Signed-off-by: Patrick McHardy IPS_CONFIRMED_BIT is set under nf_conntrack_lock (in __nf_conntrack_confirm()), we probably want to add a synchronisation under ct->lock as well, or __nf_ct_refresh_acct() could set ct->timeout.expires to extra_jiffies, while a different cpu could confirm the conntrack. Following patch as RFC diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c index 5f72b94..24034c4 100644 --- a/net/netfilter/nf_conntrack_core.c +++ b/net/netfilter/nf_conntrack_core.c @@ -408,6 +408,7 @@ __nf_conntrack_confirm(struct sk_buff *skb) NF_CT_ASSERT(!nf_ct_is_confirmed(ct)); pr_debug("Confirming conntrack %p\n", ct); + spin_lock_bh(&ct->lock); spin_lock_bh(&nf_conntrack_lock); /* See if there's one in the list already, including reverse: @@ -435,6 +436,7 @@ __nf_conntrack_confirm(struct sk_buff *skb) set_bit(IPS_CONFIRMED_BIT, &ct->status); NF_CT_STAT_INC(net, insert); spin_unlock_bh(&nf_conntrack_lock); + spin_unlock_bh(&ct->lock); help = nfct_help(ct); if (help && help->helper) nf_conntrack_event_cache(IPCT_HELPER, ct); @@ -446,6 +448,7 @@ __nf_conntrack_confirm(struct sk_buff *skb) out: NF_CT_STAT_INC(net, insert_failed); spin_unlock_bh(&nf_conntrack_lock); + spin_unlock_bh(&ct->lock); return NF_DROP; } EXPORT_SYMBOL_GPL(__nf_conntrack_confirm); @@ -848,6 +851,7 @@ void __nf_ct_refresh_acct(struct nf_conn *ct, NF_CT_ASSERT(ct->timeout.data == (unsigned long)ct); NF_CT_ASSERT(skb); + spin_lock_bh(&ct->lock); /* Only update if this is not a fixed timeout */ if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status)) goto acct; @@ -871,13 +875,12 @@ acct: acct = nf_conn_acct_find(ct); if (acct) { - spin_lock_bh(&ct->lock); acct[CTINFO2DIR(ctinfo)].packets++; acct[CTINFO2DIR(ctinfo)].bytes += skb->len - skb_network_offset(skb); - spin_unlock_bh(&ct->lock); } } + spin_unlock_bh(&ct->lock); } EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/