Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757241Ab3HZQ3r (ORCPT ); Mon, 26 Aug 2013 12:29:47 -0400 Received: from e38.co.us.ibm.com ([32.97.110.159]:56835 "EHLO e38.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752086Ab3HZQ3p (ORCPT ); Mon, 26 Aug 2013 12:29:45 -0400 Date: Mon, 26 Aug 2013 09:29:28 -0700 From: "Paul E. McKenney" To: Dave Jones , Linux Kernel Cc: rostedt@goodmis.org Subject: Re: suspicious RCU usage (perf) Message-ID: <20130826162928.GQ3871@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <20130826145838.GA8377@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130826145838.GA8377@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13082616-5518-0000-0000-00001177FBD0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3822 Lines: 66 On Mon, Aug 26, 2013 at 10:58:38AM -0400, Dave Jones wrote: > Another day, another rcu backtrace.. > This says rc6, but it's pretty darn close to rc7, I think it was running > a build from Friday. Could you please send your .config? Also, were you running ftrace, perf, RCU event tracing, or what? Looks like you are running ftrace, but I though Steven had set that up so that it could be called from an extended quiescent state. Thanx, Paul > [260431.854524] =============================== > [260431.855485] [ INFO: suspicious RCU usage. ] > [260431.856437] 3.11.0-rc6+ #12 Not tainted > [260431.857377] ------------------------------- > [260431.858318] include/linux/rcupdate.h:779 rcu_read_lock() used illegally while idle! > [260431.859278] other info that might help us debug this: > [260431.862144] RCU used illegally from idle CPU! > rcu_scheduler_active = 1, debug_locks = 0 > [260431.864990] RCU used illegally from extended quiescent state! > [260431.865949] 1 lock held by trinity-kid3/15917: > [260431.866901] #0: (rcu_read_lock){.+.+..}, at: [] __perf_event_overflow+0x100/0x320 > [260431.867896] stack backtrace: > [260431.869815] CPU: 0 PID: 15917 Comm: trinity-kid3 Not tainted 3.11.0-rc6+ #12 > [260431.871885] 0000000000000000 ffff8801095d3ad0 ffffffff816f9c6f ffff88023ce86950 > [260431.872912] ffff8801095d3b00 ffffffff810be6a7 ffff880079695cd0 0000000000000000 > [260431.873910] ffff8801095d3c00 0000000000000000 ffff8801095d3b80 ffffffff81146ef4 > [260431.874909] Call Trace: > [260431.875883] [] dump_stack+0x54/0x74 > [260431.876869] [] lockdep_rcu_suspicious+0xe7/0x120 > [260431.877852] [] __perf_event_overflow+0x2a4/0x320 > [260431.878834] [] ? __perf_event_overflow+0x100/0x320 > [260431.879811] [] ? __perf_event_overflow+0x1bc/0x320 > [260431.880784] [] ? ftrace_call+0x5/0x2f > [260431.881758] [] perf_swevent_overflow+0x51/0xe0 > [260431.882728] [] perf_swevent_event+0x5f/0x90 > [260431.883685] [] perf_tp_event+0x109/0x4f0 > [260431.884637] [] ? perf_tp_event+0x322/0x4f0 > [260431.885586] [] ? rcu_eqs_enter_common+0x5b/0x420 > [260431.886539] [] ? task_work_run+0xe0/0xe0 > [260431.887486] [] perf_ftrace_function_call+0xc0/0xd0 > [260431.888417] [] ? ftrace_ops_control_func+0xe7/0x110 > [260431.889353] [] ? task_work_run+0xe0/0xe0 > [260431.890281] [] ? rcu_eqs_enter_common+0x5b/0x420 > [260431.891191] [] ftrace_ops_control_func+0xe7/0x110 > [260431.892088] [] ftrace_call+0x5/0x2f > [260431.892975] [] ? ftrace_ops_control_func+0x6b/0x110 > [260431.893862] [] ? ftrace_call+0x5/0x2f > [260431.894745] [] ? local_clock+0x3f/0x50 > [260431.895631] [] ? debug_lockdep_rcu_enabled+0x5/0x40 > [260431.896516] [] ? debug_lockdep_rcu_enabled+0x5/0x40 > [260431.897387] [] ? rcu_eqs_enter_common+0x5b/0x420 > [260431.898264] [] rcu_eqs_enter+0x64/0xa0 > [260431.899133] [] rcu_user_enter+0x13/0x20 > [260431.899999] [] user_enter+0x6a/0xd0 > [260431.900859] [] syscall_trace_leave+0x78/0x150 > [260431.901712] [] int_check_syscall_exit_work+0x34/0x3d > -- 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/