Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752983AbbGNQI2 (ORCPT ); Tue, 14 Jul 2015 12:08:28 -0400 Received: from e39.co.us.ibm.com ([32.97.110.160]:54432 "EHLO e39.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752486AbbGNQI1 (ORCPT ); Tue, 14 Jul 2015 12:08:27 -0400 X-Helo: d03dlp03.boulder.ibm.com X-MailFrom: paulmck@linux.vnet.ibm.com X-RcptTo: linux-kernel@vger.kernel.org Date: Tue, 14 Jul 2015 09:08:16 -0700 From: "Paul E. McKenney" To: Fabio Estevam Cc: Russell King , "linux-arm-kernel@lists.infradead.org" , Peter Zijlstra , rostedt@goodmis.org, linux-kernel Subject: Re: mx6: suspicious RCU usage Message-ID: <20150714160816.GA18142@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <20150714160006.GI3717@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150714160006.GI3717@linux.vnet.ibm.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 15071416-0033-0000-0000-00000526AC28 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4371 Lines: 113 On Tue, Jul 14, 2015 at 09:00:06AM -0700, Paul E. McKenney wrote: > On Tue, Jul 14, 2015 at 12:54:15PM -0300, Fabio Estevam wrote: > > Hi, > > > > I am running 4.2-rc2 on a mx6q board and I see the following warning > > when doing a suspend/resume cycle: > > > > $ echo mem > /sys/power/state > > > > PM: Syncing filesystems ... done. > > Freezing user space processes ... (elapsed 0.003 seconds) done. > > Freezing remaining freezable tasks ... (elapsed 0.003 seconds) done. > > Suspending console(s) (use no_console_suspend to debug) > > > > (Press GPIO button to wake up the system) > > > > PM: suspend of devices complete after 101.667 msecs > > PM: suspend devices took 0.110 seconds > > PM: late suspend of devices complete after 11.073 msecs > > PM: noirq suspend of devices complete after 9.432 msecs > > Disabling non-boot CPUs ... > > Does this patch help? > > https://lkml.org/lkml/2015/5/12/885 Or this one, if this is ARM rather than ARM64: https://lkml.org/lkml/2015/5/12/892 Thanx, Paul > > =============================== > > [ INFO: suspicious RCU usage. ] > > 4.2.0-rc2 #247 Not tainted > > ------------------------------- > > kernel/sched/fair.c:5032 suspicious rcu_dereference_check() usage! > > > > other info that might help us debug this: > > > > > > RCU used illegally from offline CPU! > > rcu_scheduler_active = 1, debug_locks = 0 > > 3 locks held by swapper/1/0: > > #0: ((cpu_died).wait.lock){......}, at: [<800643e0>] complete+0x1c/0x4c > > #1: (&p->pi_lock){-.-.-.}, at: [<8004f7e8>] try_to_wake_up+0x34/0x3c8 > > #2: (rcu_read_lock){......}, at: [<80057b68>] select_task_rq_fair+0x64/0x9e8 > > > > stack backtrace: > > CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.2.0-rc2 #247 > > Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree) > > Backtrace: > > [<80012ee8>] (dump_backtrace) from [<80013084>] (show_stack+0x18/0x1c) > > r6:000013a8 r5:00000000 r4:00000000 r3:00000000 > > [<8001306c>] (show_stack) from [<8078d364>] (dump_stack+0x88/0xa4) > > [<8078d2dc>] (dump_stack) from [<800676d8>] (lockdep_rcu_suspicious+0xbc/0x11c) > > r5:809497c4 r4:be076780 > > [<8006761c>] (lockdep_rcu_suspicious) from [<80058200>] > > (select_task_rq_fair+0x6fc/0x9e8) > > r7:80a94fc0 r6:00000001 r5:00000000 r4:00000000 > > [<80057b04>] (select_task_rq_fair) from [<8004f8cc>] > > (try_to_wake_up+0x118/0x3c8) > > r10:80a94fc0 r9:00000000 r8:00000000 r7:80000093 r6:80a98b2c r5:bd748f8c > > r4:bd748b80 > > [<8004f7b4>] (try_to_wake_up) from [<8004fb90>] > > (default_wake_function+0x14/0x18) > > r10:00000003 r9:8004fb7c r8:00000000 r7:00000000 r6:80a9dc34 r5:00000001 > > r4:80a9dc28 > > [<8004fb7c>] (default_wake_function) from [<80063b18>] > > (__wake_up_common+0x58/0x98) > > [<80063ac0>] (__wake_up_common) from [<80063b74>] (__wake_up_locked+0x1c/0x24) > > r10:80a98b2c r9:807993ac r8:80a98a10 r7:80afc552 r6:60000093 r5:80a9dc10 > > r4:80a9dc14 > > [<80063b58>] (__wake_up_locked) from [<80064400>] (complete+0x3c/0x4c) > > [<800643c4>] (complete) from [<807870e0>] (cpu_die+0x3c/0xa4) > > r6:80a923e4 r5:00000001 r4:80a98968 r3:00000002 > > [<807870a4>] (cpu_die) from [<80010798>] (arch_cpu_idle_dead+0x10/0x14) > > r5:80a989c4 r4:00000000 > > [<80010788>] (arch_cpu_idle_dead) from [<80064798>] > > (cpu_startup_entry+0x1d8/0x200) > > [<800645c0>] (cpu_startup_entry) from [<80015e34>] > > (secondary_start_kernel+0x120/0x13c) > > r7:80aff360 > > [<80015d14>] (secondary_start_kernel) from [<1000962c>] (0x1000962c) > > r5:00000015 r4:4e08806a > > CPU1: shutdown > > CPU2: shutdown > > CPU3: shutdown > > Enabling non-boot CPUs ... > > CPU1 is up > > CPU2 is up > > CPU3 is up > > PM: noirq resume of devices complete after 2.185 msecs > > PM: early resume of devices complete after 2.786 msecs > > PM: resume of devices complete after 204.223 msecs > > PM: resume devices took 0.200 seconds > > ata1: SATA link down (SStatus 0 SControl 300) > > PM: Finishing wakeup. > > Restarting tasks ... done. > > > > I haven't started bisecting it yet, but if someone has some ideas, > > please let me know. > > > > Regards, > > > > Fabio Estevam > > -- 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/