From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: [PATCH] [PATCH] Fix deadlock in af_packet while stressing raw ethernet socket interface Date: Tue, 12 Jul 2011 08:58:48 +0200 Message-ID: <1310453928.2860.32.camel@edumazet-laptop> References: <78567a0a1d2999f06d8f.1307768649@meeusr-laptop> <20110711.202717.1764669415135298036.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: David Miller , netdev@vger.kernel.org To: Ronny Meeus Return-path: Received: from mail-ww0-f42.google.com ([74.125.82.42]:53061 "EHLO mail-ww0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751553Ab1GLG65 (ORCPT ); Tue, 12 Jul 2011 02:58:57 -0400 Received: by wwg11 with SMTP id 11so2818612wwg.1 for ; Mon, 11 Jul 2011 23:58:56 -0700 (PDT) In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: Le mardi 12 juillet 2011 =C3=A0 08:38 +0200, Ronny Meeus a =C3=A9crit : > On Tue, Jul 12, 2011 at 5:27 AM, David Miller w= rote: > > From: Ronny Meeus > > Date: Sat, 11 Jun 2011 07:04:09 +0200 > > > >> I was running a test: 1 application was sending raw Ethernet packe= ts > >> on a physical looped interface while a second application was > >> receiving packets, so the latter application receives each packet = 2 > >> times (once while sending from the context of the first applicatio= n > >> and a second time while receiving from the hardware). After some > >> time, the test blocks due to a spinlock reentrance issue in > >> af_packet. Both the sending application and the softIRQ receiving > >> packets enter the spinlock code. After applying the patch below, t= he > >> issue is resolved. > >> > >> Signed-off-by: Ronny Meeus > > > > The packet receive hooks should always be called with software > > interrupts disabled, it is a bug if this is not happening. Your > > patch should not be necessary at all. > > > > >=20 > Can you be a bit more specific on where the software interrupts shoul= d > be disabled? >=20 > Below you find the information I get after switching on the spin_lock > issue detection in the kernel. > In this run also I-PIPE was active but this issue is also seen with > I-PIPE disabled. >=20 This seems a bug, but in softirq handling in your arch > [ 96.450034] BUG: spinlock recursion on CPU#0, send_eth_socket/1907 > [ 96.540451] lock: eaeb8c9c, .magic: dead4ead, .owner: > send_eth_socket/1907, .owner_cpu: 0 > [ 96.656060] Call Trace: (unreliable)0161000 success=3D90] [c000789= c] > show_stack+0x78/0x18c160001 > [ 96.827988] [efff3dd0] [c01e2a50] spin_bug+0xa8/0xc0=3D0000162000 = succ > [ 96.920712] [efff3df0] [c01e2b9c] do_raw_spin_lock+0x70/0x1c4ount=3D= 0000163000 > [ 97.022823] [efff3e20] [c0388d88] _raw_spin_lock+0x10/0x2001 > [ 97.121800] [efff3e30] [c03391a0] tpacket_rcv+0x274/0x61c164001 > [ 97.219733] [efff3e80] [c02d5970] __netif_receive_skb+0x1a8/0x36c0= 000165001 > [ 97.326001] [efff3eb0] [c02d6234] netif_receive_skb+0x98/0xacess=3D= 0000166001 > [ 97.427060] [efff3ee0] [c029e6c4] ingress_rx_default_dqrr+0x42c/0x= 4b8 > [ 97.504194] [efff3f10] [c02ba524] qman_poll_dqrr+0x1e0/0x284 > [ 97.571948] [efff3f50] [c029ff3c] dpaa_eth_poll+0x34/0xd0 > [ 97.636579] [efff3f70] [c02d6514] net_rx_action+0xc0/0x1e8 > [ 97.702256] [efff3fa0] [c0034d28] __do_softirq+0x138/0x210 > [ 97.767928] [efff3ff0] [c0010128] call_do_softirq+0x14/0x24 > [ 97.834641] [ec479a90] [c0004a00] do_softirq+0xb4/0xec We got an IRQ, and we start do_softirq() from irq_exit() > [ 97.896148] [ec479ab0] [c0034a44] irq_exit+0x60/0xb8 > [ 97.955573] [ec479ac0] [c000a490] __ipipe_do_IRQ+0x88/0xc0 > [ 98.021253] [ec479ae0] [c0070214] __ipipe_sync_stage+0x1f0/0x27c > [ 98.093176] [ec479b20] [c0009f28] __ipipe_handle_irq+0x1b8/0x1e8 > [ 98.165106] [ec479b50] [c000a210] __ipipe_grab_irq+0x18c/0x1bc > [ 98.234947] [ec479b80] [c0011520] __ipipe_ret_from_except+0x0/0xc > [ 98.307915] --- Exception: 501 at __packet_get_status+0x48/0x70 > [ 98.307920] LR =3D __packet_get_status+0x44/0x70 > [ 98.436082] [ec479c40] [00000578] 0x578 (unreliable) > [ 98.495524] [ec479c50] [c0338360] packet_lookup_frame+0x48/0x70 > [ 98.566405] [ec479c60] [c03391b4] tpacket_rcv+0x288/0x61c Here we were in BH disabled section, since dev_queue_xmit() contains : rcu_read_lock_bh() > [ 98.631037] [ec479cb0] [c02d762c] dev_hard_start_xmit+0x164/0x588 > [ 98.704003] [ec479cf0] [c0338d6c] packet_sendmsg+0x8c4/0x988 > [ 98.771758] [ec479d70] [c02c3838] sock_sendmsg+0x90/0xb4 > [ 98.835348] [ec479e40] [c02c4420] sys_sendto+0xdc/0x120 > [ 98.897891] [ec479f10] [c02c57d0] sys_socketcall+0x148/0x210 > [ 98.965648] [ec479f40] [c001084c] ret_from_syscall+0x0/0x3c > [ 99.032361] --- Exception: c01 at 0x48051f00 > [ 99.032365] LR =3D 0x4808e030 > [ 100.563009] BUG: spinlock lockup on CPU#0, send_eth_socket/1907, e= aeb8c9c > [ 100.644283] Call Trace: > [ 100.673480] [efff3db0] [c000789c] show_stack+0x78/0x18c (unreliabl= e) > [ 100.749589] [efff3df0] [c01e2c94] do_raw_spin_lock+0x168/0x1c4 > [ 100.819430] [efff3e20] [c0388d88] _raw_spin_lock+0x10/0x20 > [ 100.885102] [efff3e30] [c03391a0] tpacket_rcv+0x274/0x61c > [ 100.949733] [efff3e80] [c02d5970] __netif_receive_skb+0x1a8/0x36c > [ 101.022699] [efff3eb0] [c02d6234] netif_receive_skb+0x98/0xac > [ 101.091497] [efff3ee0] [c029e6c4] ingress_rx_default_dqrr+0x42c/0x= 4b8 > [ 101.168628] [efff3f10] [c02ba524] qman_poll_dqrr+0x1e0/0x284 > [ 101.236385] [efff3f50] [c029ff3c] dpaa_eth_poll+0x34/0xd0 > [ 101.301016] [efff3f70] [c02d6514] net_rx_action+0xc0/0x1e8 > [ 101.366692] [efff3fa0] [c0034d28] __do_softirq+0x138/0x210 > [ 101.432364] [efff3ff0] [c0010128] call_do_softirq+0x14/0x24 > [ 101.499078] [ec479a90] [c0004a00] do_softirq+0xb4/0xec > [ 101.560585] [ec479ab0] [c0034a44] irq_exit+0x60/0xb8 > [ 101.620003] [ec479ac0] [c000a490] __ipipe_do_IRQ+0x88/0xc0 > [ 101.685678] [ec479ae0] [c0070214] __ipipe_sync_stage+0x1f0/0x27c > [ 101.757601] [ec479b20] [c0009f28] __ipipe_handle_irq+0x1b8/0x1e8 > [ 101.829523] [ec479b50] [c000a210] __ipipe_grab_irq+0x18c/0x1bc > [ 101.899363] [ec479b80] [c0011520] __ipipe_ret_from_except+0x0/0xc > [ 101.972333] --- Exception: 501 at __packet_get_status+0x48/0x70 > [ 101.972338] LR =3D __packet_get_status+0x44/0x70 > [ 102.100490] [ec479c40] [00000578] 0x578 (unreliable) > [ 102.159929] [ec479c50] [c0338360] packet_lookup_frame+0x48/0x70 > [ 102.230810] [ec479c60] [c03391b4] tpacket_rcv+0x288/0x61c > [ 102.295442] [ec479cb0] [c02d762c] dev_hard_start_xmit+0x164/0x588 > [ 102.368407] [ec479cf0] [c0338d6c] packet_sendmsg+0x8c4/0x988 > [ 102.436162] [ec479d70] [c02c3838] sock_sendmsg+0x90/0xb4 > [ 102.499747] [ec479e40] [c02c4420] sys_sendto+0xdc/0x120 > [ 102.562296] [ec479f10] [c02c57d0] sys_socketcall+0x148/0x210 > [ 102.630052] [ec479f40] [c001084c] ret_from_syscall+0x0/0x3c > [ 102.696773] --- Exception: c01 at 0x48051f00 > [ 102.696777] LR =3D 0x4808e030 >=20 > Ronny > -- > To unsubscribe from this list: send the line "unsubscribe netdev" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html