From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752043AbbCOXcw (ORCPT ); Sun, 15 Mar 2015 19:32:52 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:46594 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751477AbbCOXcv (ORCPT ); Sun, 15 Mar 2015 19:32:51 -0400 Message-ID: <55061690.3080006@oracle.com> Date: Sun, 15 Mar 2015 19:32:32 -0400 From: Sasha Levin User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.5.0 MIME-Version: 1.0 To: paulmck@linux.vnet.ibm.com CC: Josh Triplett , Steven Rostedt , Mathieu Desnoyers , Lai Jiangshan , LKML , Dave Jones Subject: Re: rcu: frequent rcu lockups References: <5500A329.9060509@oracle.com> <20150311204108.GM5412@linux.vnet.ibm.com> <5500BF51.5000806@oracle.com> <20150311230133.GN5412@linux.vnet.ibm.com> <5500CA80.9010007@oracle.com> <20150311231613.GO5412@linux.vnet.ibm.com> <55018663.2060107@oracle.com> <55018745.3080109@oracle.com> <20150312140749.GP5412@linux.vnet.ibm.com> <20150313173943.GA2671@linux.vnet.ibm.com> <20150315204302.GA22721@linux.vnet.ibm.com> In-Reply-To: <20150315204302.GA22721@linux.vnet.ibm.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit X-Source-IP: userv0021.oracle.com [156.151.31.71] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/15/2015 04:43 PM, Paul E. McKenney wrote: > But I did find a bug that would result in the other warnings, and could > also result in too-short grace periods, which could in turn result in > arbitrarily arbitrary misbehavior. The patch below, which is also on > its way into -next, should fix this. Please let me know how it does > for you. I've stopped seeing the warnings I've previously reported, but started seeing a new one: [ 788.564596] WARNING: CPU: 12 PID: 9711 at kernel/rcu/tree.c:2201 rcu_report_qs_rnp+0x42e/0x5a0() [ 788.568123] Modules linked in: [ 788.568123] CPU: 12 PID: 9711 Comm: trinity-main Not tainted 4.0.0-rc3-next-20150313-sasha-00041-g83a3dc8-dirty #2078 [ 788.568123] ffff8803a1ba0000 00000000400df16a ffff880442807cc8 ffffffffb1ab01ca [ 788.568123] 0000000000000000 0000000000000000 ffff880442807d18 ffffffffa71e261a [ 788.568123] dffffc0000000000 ffffffffa733d2ee ffff880442807d28 ffffffffb4724000 [ 788.568123] Call Trace: [ 788.568123] dump_stack (lib/dump_stack.c:52) [ 788.568123] warn_slowpath_common (kernel/panic.c:447) [ 788.568123] ? rcu_report_qs_rnp (kernel/rcu/tree.c:2201 (discriminator 3)) [ 788.568123] warn_slowpath_null (kernel/panic.c:481) [ 788.568123] rcu_report_qs_rnp (kernel/rcu/tree.c:2201 (discriminator 3)) [ 788.568123] rcu_process_callbacks (kernel/rcu/tree.c:2302 kernel/rcu/tree.c:2338 kernel/rcu/tree.c:2824 kernel/rcu/tree.c:2857) [ 788.568123] __do_softirq (kernel/softirq.c:273 include/linux/jump_label.h:114 include/trace/events/irq.h:126 kernel/softirq.c:274) [ 788.568123] irq_exit (kernel/softirq.c:350 kernel/softirq.c:391) [ 788.568123] smp_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:918) [ 788.568123] apic_timer_interrupt (arch/x86/kernel/entry_64.S:920) [ 788.568123] ? mark_held_locks (kernel/locking/lockdep.c:2525) [ 788.568123] finish_task_switch (kernel/sched/core.c:2231) [ 788.568123] __schedule (kernel/sched/core.c:2337 kernel/sched/core.c:2795) [ 788.568123] schedule (./arch/x86/include/asm/bitops.h:311 (discriminator 1) kernel/sched/core.c:2824 (discriminator 1)) [ 788.568123] schedule_preempt_disabled (kernel/sched/core.c:2856) [ 788.568123] mutex_lock_nested (kernel/locking/mutex.c:585 kernel/locking/mutex.c:623) [ 788.568123] kernfs_iop_permission (fs/kernfs/inode.c:366) [ 788.568123] __inode_permission (fs/namei.c:374 fs/namei.c:408) [ 788.568123] inode_permission (fs/namei.c:460) [ 788.568123] link_path_walk (fs/namei.c:1520 fs/namei.c:1782) [ 788.568123] path_init (fs/namei.c:1947) [ 788.568123] path_lookupat (fs/namei.c:1989) [ 788.568123] filename_lookup (fs/namei.c:2025) [ 788.568123] user_path_at_empty (fs/namei.c:2189) [ 788.568123] user_path_at (fs/namei.c:2200) [ 788.568123] vfs_fstatat (fs/stat.c:106) [ 788.568123] SYSC_newfstatat (fs/stat.c:298) [ 788.568123] SyS_newfstatat (fs/stat.c:291) [ 788.568123] tracesys_phase2 (arch/x86/kernel/entry_64.S:347) Thanks, Sasha