Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755106AbcJSEsV (ORCPT ); Wed, 19 Oct 2016 00:48:21 -0400 Received: from mail-qt0-f179.google.com ([209.85.216.179]:33489 "EHLO mail-qt0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750768AbcJSEsL (ORCPT ); Wed, 19 Oct 2016 00:48:11 -0400 MIME-Version: 1.0 From: Siva Reddy Kallam Date: Wed, 19 Oct 2016 10:18:09 +0530 Message-ID: Subject: Re: tg3 BUG: spinlock lockup suspected To: Meelis Roos Cc: Linux Netdev List , sparclinux@vger.kernel.org, Linux Kernel list , Deepak Khungar Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4198 Lines: 77 On Mon, Oct 17, 2016 at 6:35 PM, Meelis Roos wrote: >> > Now I reproduced the bug even with 4.7-rc1 so it is older than 4.7. Will >> > test further. >> >> It gets stranger and stranger - my old 4.7 image worked fine, freshly >> compiled 4.7 exhibits the same problem. >> >> Toolchain has not changed, that I know for sure. >> >> What may have changed is kernel .config. My old conf was with whatever I >> had during 4.7. Then I upgraded to 4.8-rc3 and then 4.8 and selected >> values for "make oldconfig" new entries. Then went back to 4.7-rc1 and >> then to 4.7 with this config, answering quiestion about new options when >> any appeared. Diff is not available since I do not have the old configs >> archived. > > I did some more digging. Found an older configuration that is working > and recreated a newer one that is bad, for the same 4.7 kernel. This is > reproducible now, from "make clean" state. > > Working config from 4.7-rc4 attached as config-4.7, broken config from > 4.7 attached as config-4.7-bad. > > Will try to bisect the configs as time permits. But looking at the > stack traces, the issue is probably timing related, when ip and dhclient > do something with the same lock. seq_read that outputs stats could be > reading /proc/net/dev that reads counters from each interface. > > ifupdown seems to use the following for dhcp interfaces: > up > [[/bin/ip link set dev %iface% address %hwaddress%]] > /sbin/dhclient -v -pf /run/dhclient.%iface%.pid -lf /var/lib/dhcp/dhclient.%iface%.leases -I -df /var/lib/dhcp/dhclient6.%iface%.leases %iface% \ > ... > > so ip link is setting link up, this creates some work for the > background, and the dhclient goes adn reads /proc/net/dev, and lockup is > suspected but not proven? > > I started a loop for test, doing cat /proc/net/dev in a loop and at the > same link link up and down from console, but up and down is slow process > and the loop did not seem to trigger the warning over night, so it was > not so simple. > I am busy with other priority tasks. One of my colleague Deepak will work this with you. I added him to CC list. Thanks. > >> > > [ 83.716570] BUG: spinlock lockup suspected on CPU#0, dhclient/1014 >> > > [ 83.797819] lock: 0xfff000123c8e4a08, .magic: dead4ead, .owner: ip/1001, .owner_cpu: 1 >> > > [ 83.903130] CPU: 0 PID: 1014 Comm: dhclient Not tainted 4.8.0 #4 >> > > [ 83.982129] Call Trace: >> > > [ 84.014160] [00000000004b7220] spin_dump+0x60/0xa0 >> > > [ 84.078203] [00000000004b73a0] do_raw_spin_lock+0xa0/0x120 >> > > [ 84.106344] IPv6: ADDRCONF(NETDEV_UP): eth0: link is not ready >> > > [ 84.107193] ip (1001) used greatest stack depth: 2168 bytes left >> > > [ 84.306955] [000000000092c0d0] _raw_spin_lock_bh+0x30/0x40 >> > > [ 84.380188] [00000000100822cc] tg3_get_stats64+0xc/0x80 [tg3] >> > > [ 84.456885] [00000000007fac8c] dev_get_stats+0x2c/0xc0 >> > > [ 84.525506] [000000000081a4e8] dev_seq_printf_stats+0x8/0xe0 >> > > [ 84.600986] [000000000081a5e4] dev_seq_show+0x24/0x40 >> > > [ 84.668467] [00000000005cb6c4] seq_read+0x2c4/0x440 >> > > [ 84.733656] [000000000060b97c] proc_reg_read+0x3c/0x80 >> > > [ 84.802282] [00000000005a219c] __vfs_read+0x1c/0x140 >> > > [ 84.868613] [00000000005a2310] vfs_read+0x50/0x100 >> > > [ 84.932662] [00000000005a265c] SyS_read+0x3c/0xa0 >> > > [ 84.995573] [00000000004061d4] linux_sparc_syscall32+0x34/0x60 >> > > [ 85.073748] * CPU[ 0]: TSTATE[00000044f0001a22] TPC[00000000f79a16b0] TNPC[00000000f79a16b4] TASK[dhclient:1014] >> > > [ 85.208732] TPC[f79a16b0] O7[f79405c8] I7[0] RPC[0] >> > > [ 85.287633] CPU[ 1]: TSTATE[0000004480001605] TPC[00000000004b26f0] TNPC[00000000004d0b0c] TASK[swapper/1:0] >> > > [ 85.420338] TPC[trace_hardirqs_off+0x10/0x20] O7[rcu_idle_enter+0x64/0xa0] I7[cpu_startup_entry+0x1b0/0x240] RPC[rest_init+0x178/0x1a0] >> > > [ 85.664600] tg3 0000:00:02.0 eth0: Link is up at 100 Mbps, full duplex >> > > [ 85.750515] tg3 0000:00:02.0 eth0: Flow control is off for TX and off for RX >> > > [ 85.843994] IPv6: ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready > > -- > Meelis Roos (mroos@linux.ee)