From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Warren Subject: Re: [PATCH v2] ipv6: Don't depend on per socket memory for neighbour discovery messages Date: Tue, 03 Sep 2013 12:03:14 -0600 Message-ID: <52262462.80308@wwwdotorg.org> References: <52261A12.3060203@wwwdotorg.org> <20130903172736.GB21729@order.stressinduktion.org> <52261F68.70907@wwwdotorg.org> <1378230697.7360.38.camel@edumazet-glaptop> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: Thomas Graf , davem@davemloft.net, netdev@vger.kernel.org, Fabio Estevam To: Eric Dumazet Return-path: Received: from avon.wwwdotorg.org ([70.85.31.133]:54045 "EHLO avon.wwwdotorg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754571Ab3ICSDS (ORCPT ); Tue, 3 Sep 2013 14:03:18 -0400 In-Reply-To: <1378230697.7360.38.camel@edumazet-glaptop> Sender: netdev-owner@vger.kernel.org List-ID: On 09/03/2013 11:51 AM, Eric Dumazet wrote: > On Tue, 2013-09-03 at 11:42 -0600, Stephen Warren wrote: > >> I don't see any extra messages from PROVE_LOCKING related to networking. >> There is a single extra message from inside the audio driver, but that's >> not networking-related at all. > > LOCKDEP is automatically disabled at first splat. > > Please try a kernel without audio driver ;) Ah, OK. Now I do see something from ipv6: > [ 25.327622] > [ 25.329142] ============================================= > [ 25.334533] [ INFO: possible recursive locking detected ] > [ 25.339927] 3.11.0-rc7-next-20130830-00024-g209b4d8-dirty #17 Not tainted > [ 25.346705] --------------------------------------------- > [ 25.352095] login/704 is trying to acquire lock: > [ 25.356705] (&ndev->lock){++--..}, at: [] ipv6_chk_mcast_addr+0x5c/0x200 > [ 25.364405] > [ 25.364405] but task is already holding lock: > [ 25.370230] (&ndev->lock){++--..}, at: [] addrconf_rs_timer+0x18/0x134 > [ 25.377741] > [ 25.377741] other info that might help us debug this: > [ 25.384261] Possible unsafe locking scenario: > [ 25.384261] > [ 25.390174] CPU0 > [ 25.392614] ---- > [ 25.395053] lock(&ndev->lock); > [ 25.398286] lock(&ndev->lock); > [ 25.401518] > [ 25.401518] *** DEADLOCK *** > [ 25.401518] > [ 25.407433] May be due to missing lock nesting notation > [ 25.407433] > [ 25.414214] 4 locks held by login/704: > [ 25.417955] #0: (((&ndev->rs_timer))){+.-...}, at: [] call_timer_fn+0x0/0xe4 > [ 25.426076] #1: (&ndev->lock){++--..}, at: [] addrconf_rs_timer+0x18/0x134 > [ 25.434018] #2: (rcu_read_lock){.+.+..}, at: [] ndisc_send_skb+0x58/0x3dc > [ 25.441876] #3: (rcu_read_lock){.+.+..}, at: [] ipv6_chk_mcast_addr+0x0/0x200 > [ 25.450079] > [ 25.450079] stack backtrace: > [ 25.454436] CPU: 0 PID: 704 Comm: login Not tainted 3.11.0-rc7-next-20130830-00024-g209b4d8-dirty #17 > [ 25.463674] [] (unwind_backtrace+0x0/0x138) from [] (show_stack+0x10/0x14) > [ 25.472297] [] (show_stack+0x10/0x14) from [] (dump_stack+0x80/0xc4) > [ 25.480394] [] (dump_stack+0x80/0xc4) from [] (validate_chain.isra.24+0x74c/0x8c8) > [ 25.489696] [] (validate_chain.isra.24+0x74c/0x8c8) from [] (__lock_acquire+0x3bc/0xa80) > [ 25.499518] [] (__lock_acquire+0x3bc/0xa80) from [] (lock_acquire+0x60/0x74) > [ 25.508305] [] (lock_acquire+0x60/0x74) from [] (_raw_read_lock_bh+0x4c/0x5c) > [ 25.517175] [] (_raw_read_lock_bh+0x4c/0x5c) from [] (ipv6_chk_mcast_addr+0x5c/0x200) > [ 25.526740] [] (ipv6_chk_mcast_addr+0x5c/0x200) from [] (ip6_finish_output2+0x298/0x62c) > [ 25.536563] [] (ip6_finish_output2+0x298/0x62c) from [] (ndisc_send_skb+0x204/0x3dc) > [ 25.546037] [] (ndisc_send_skb+0x204/0x3dc) from [] (addrconf_rs_timer+0x108/0x134) > [ 25.555425] [] (addrconf_rs_timer+0x108/0x134) from [] (call_timer_fn+0x6c/0xe4) > [ 25.564553] [] (call_timer_fn+0x6c/0xe4) from [] (run_timer_softirq+0x180/0x22c) > [ 25.573691] [] (run_timer_softirq+0x180/0x22c) from [] (__do_softirq+0x100/0x1fc) > [ 25.582905] [] (__do_softirq+0x100/0x1fc) from [] (irq_exit+0xa8/0xf4) > [ 25.591166] [] (irq_exit+0xa8/0xf4) from [] (handle_IRQ+0x3c/0x94) > [ 25.599078] [] (handle_IRQ+0x3c/0x94) from [] (gic_handle_irq+0x28/0x5c) > [ 25.607511] [] (gic_handle_irq+0x28/0x5c) from [] (__irq_usr+0x3c/0x60) > [ 25.615855] Exception stack(0xee0d9fb0 to 0xee0d9ff8) > [ 25.620901] 9fa0: 5c026e4c c9ce71d5 538e8b11 f2a43512 > [ 25.629072] 9fc0: 49f97e42 7a179ff1 9c755700 9b933273 8b7a2401 6d6222ee 7b8908fd 1df2f704 > [ 25.637243] 9fe0: 2664e738 bec3ef10 b6d440e9 b6d43d58 900f0030 ffffffff