Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757906Ab2JXQpB (ORCPT ); Wed, 24 Oct 2012 12:45:01 -0400 Received: from mail-la0-f46.google.com ([209.85.215.46]:49749 "EHLO mail-la0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757162Ab2JXQo5 (ORCPT ); Wed, 24 Oct 2012 12:44:57 -0400 Date: Wed, 24 Oct 2012 09:42:35 -0700 From: Sergey Senozhatsky To: Dave Jones , Frederic Weisbecker , "Paul E. McKenney" , Oleg Nesterov , Serge Hallyn , linux-kernel@vger.kernel.org Subject: Re: lots of suspicious RCU traces Message-ID: <20121024164235.GA2467@swordfish> References: <20121017034918.GA13295@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20121017034918.GA13295@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 41255 Lines: 872 On (10/16/12 23:49), Dave Jones wrote: > I just triggered this while fuzz testing. All traces happened > in quick succession. > I can easily reproduce this one [ 5714.696329] =============================== [ 5714.696332] [ INFO: suspicious RCU usage. ] [ 5714.696336] 3.7.0-rc2-dbg-01220-g698b6f8-dirty #1376 Not tainted [ 5714.696338] ------------------------------- [ 5714.696341] include/linux/rcupdate.h:738 rcu_read_lock() used illegally while idle! [ 5714.696343] other info that might help us debug this: [ 5714.696347] RCU used illegally from idle CPU! rcu_scheduler_active = 1, debug_locks = 1 [ 5714.696350] RCU used illegally from extended quiescent state! [ 5714.696354] 2 locks held by coretemp-sensor/16214: [ 5714.696356] #0: (&(&sighand->siglock)->rlock){-.-...}, at: [] ptrace_notify+0x53/0x90 [ 5714.696373] #1: (rcu_read_lock){.+.+..}, at: [] __task_pid_nr_ns+0x5/0x1b0 [ 5714.696385] stack backtrace: [ 5714.696389] Pid: 16214, comm: coretemp-sensor Not tainted 3.7.0-rc2-dbg-01220-g698b6f8-dirty #1376 [ 5714.696392] Call Trace: [ 5714.696403] [] lockdep_rcu_suspicious+0xe2/0x130 [ 5714.696408] [] __task_pid_nr_ns+0x175/0x1b0 [ 5714.696413] [] ? __task_pid_nr_ns+0x5/0x1b0 [ 5714.696418] [] ptrace_do_notify+0x5f/0xb0 [ 5714.696423] [] ptrace_notify+0x64/0x90 [ 5714.696431] [] syscall_trace_leave+0x8d/0x220 [ 5714.696439] [] ? int_very_careful+0x5/0xd [ 5714.696444] [] ? trace_hardirqs_on_caller+0x105/0x190 [ 5714.696450] [] int_check_syscall_exit_work+0x34/0x3d small question, ptrace_notify() and forward calls are able to both indirectly and directly call schedule(), /* direct call from ptrace_stop()*/, should, in this case, rcu_user_enter() be called before tracehook_report_syscall_exit(regs, step) and ptrace chain? -ss > > =============================== > [ INFO: suspicious RCU usage. ] > 3.7.0-rc1+ #31 Not tainted > ------------------------------- > include/linux/rcupdate.h:738 rcu_read_lock() used illegally while idle! > > other info that might help us debug this: > > > RCU used illegally from idle CPU! > rcu_scheduler_active = 1, debug_locks = 1 > RCU used illegally from extended quiescent state! > 2 locks on stack by trinity-main/9791: > #0: held: (&(&sighand->siglock)->rlock){-.-.-.}, instance: ffff8801435dce20, at: [] ptrace_notify+0x53/0x90 > #1: blocked: (rcu_read_lock){.+.+..}, instance: ffffffff81c34e80, at: [] __task_pid_nr_ns+0x5/0x1a0 > > stack backtrace: > Pid: 9791, comm: trinity-main Not tainted 3.7.0-rc1+ #31 > Call Trace: > [] lockdep_rcu_suspicious+0xe2/0x130 > [] __task_pid_nr_ns+0x165/0x1a0 > [] ? __task_pid_nr_ns+0x5/0x1a0 > [] ptrace_do_notify+0x5f/0xb0 > [] ptrace_notify+0x64/0x90 > [] tracehook_report_syscall_exit+0x36/0xb0 > [] ? finish_task_switch+0x7c/0x120 > [] ? int_very_careful+0x5/0xd > [] syscall_trace_leave+0x79/0x150 > [] int_check_syscall_exit_work+0x34/0x3d > > =============================== > [ INFO: suspicious RCU usage. ] > 3.7.0-rc1+ #31 Not tainted > ------------------------------- > include/linux/rcupdate.h:759 rcu_read_unlock() used illegally while idle! > > other info that might help us debug this: > > > RCU used illegally from idle CPU! > rcu_scheduler_active = 1, debug_locks = 1 > RCU used illegally from extended quiescent state! > 2 locks on stack by trinity-main/9791: > #0: held: (&(&sighand->siglock)->rlock){-.-.-.}, instance: ffff8801435dce20, at: [] ptrace_notify+0x53/0x90 > #1: blocked: (rcu_read_lock){.+.+..}, instance: ffffffff81c34e80, at: [] __task_pid_nr_ns+0x5/0x1a0 > > stack backtrace: > Pid: 9791, comm: trinity-main Not tainted 3.7.0-rc1+ #31 > Call Trace: > [] lockdep_rcu_suspicious+0xe2/0x130 > [] __task_pid_nr_ns+0x131/0x1a0 > [] ? __task_pid_nr_ns+0x5/0x1a0 > [] ptrace_do_notify+0x5f/0xb0 > [] ptrace_notify+0x64/0x90 > [] tracehook_report_syscall_exit+0x36/0xb0 > [] ? finish_task_switch+0x7c/0x120 > [] ? int_very_careful+0x5/0xd > [] syscall_trace_leave+0x79/0x150 > [] int_check_syscall_exit_work+0x34/0x3d > > =============================== > [ INFO: suspicious RCU usage. ] > 3.7.0-rc1+ #31 Not tainted > ------------------------------- > include/linux/rcupdate.h:738 rcu_read_lock() used illegally while idle! > > other info that might help us debug this: > > > RCU used illegally from idle CPU! > rcu_scheduler_active = 1, debug_locks = 1 > RCU used illegally from extended quiescent state! > 3 locks on stack by migration/2/24: > #0: held: (&rq->lock){-.-.-.}, instance: ffff8801481d4a98, at: [] active_load_balance_cpu_stop+0x328/0x490 > #1: held: (&rq->lock/1){..-.-.}, instance: ffff8801483d4a98, at: [] active_load_balance_cpu_stop+0x339/0x490 > #2: blocked: (rcu_read_lock){.+.+..}, instance: ffffffff81c34e80, at: [] active_load_balance_cpu_stop+0xf4/0x490 > > stack backtrace: > Pid: 24, comm: migration/2 Not tainted 3.7.0-rc1+ #31 > Call Trace: > [] lockdep_rcu_suspicious+0xe2/0x130 > [] active_load_balance_cpu_stop+0x3ac/0x490 > [] ? active_load_balance_cpu_stop+0xf4/0x490 > [] ? cpu_stopper_thread+0xb3/0x1d0 > [] ? put_lock_stats.isra.25+0xe/0x40 > [] ? _raw_spin_unlock_irq+0x30/0x80 > [] ? get_parent_ip+0x11/0x50 > [] ? get_parent_ip+0x11/0x50 > [] ? select_task_rq_fair+0xad0/0xad0 > [] cpu_stopper_thread+0xdb/0x1d0 > [] ? sub_preempt_count+0x79/0xd0 > [] ? __schedule+0x499/0xa40 > [] ? cpu_stop_queue_work+0x80/0x80 > [] kthread+0xed/0x100 > [] ? put_lock_stats.isra.25+0xe/0x40 > [] ? kthread_create_on_node+0x160/0x160 > [] ret_from_fork+0x7c/0xb0 > [] ? kthread_create_on_node+0x160/0x160 > > =============================== > [ INFO: suspicious RCU usage. ] > 3.7.0-rc1+ #31 Not tainted > ------------------------------- > kernel/sched/fair.c:4538 suspicious rcu_dereference_check() usage! > > other info that might help us debug this: > > > RCU used illegally from idle CPU! > rcu_scheduler_active = 1, debug_locks = 1 > RCU used illegally from extended quiescent state! > 3 locks on stack by migration/2/24: > #0: held: (&rq->lock){-.-.-.}, instance: ffff8801481d4a98, at: [] active_load_balance_cpu_stop+0x328/0x490 > #1: held: (&rq->lock/1){..-.-.}, instance: ffff8801483d4a98, at: [] active_load_balance_cpu_stop+0x339/0x490 > #2: blocked: (rcu_read_lock){.+.+..}, instance: ffffffff81c34e80, at: [] active_load_balance_cpu_stop+0xf4/0x490 > > stack backtrace: > Pid: 24, comm: migration/2 Not tainted 3.7.0-rc1+ #31 > Call Trace: > [] lockdep_rcu_suspicious+0xe2/0x130 > [] active_load_balance_cpu_stop+0x435/0x490 > [] ? active_load_balance_cpu_stop+0xf4/0x490 > [] ? cpu_stopper_thread+0xb3/0x1d0 > [] ? put_lock_stats.isra.25+0xe/0x40 > [] ? _raw_spin_unlock_irq+0x30/0x80 > [] ? get_parent_ip+0x11/0x50 > [] ? get_parent_ip+0x11/0x50 > [] ? select_task_rq_fair+0xad0/0xad0 > [] cpu_stopper_thread+0xdb/0x1d0 > [] ? sub_preempt_count+0x79/0xd0 > [] ? __schedule+0x499/0xa40 > [] ? cpu_stop_queue_work+0x80/0x80 > [] kthread+0xed/0x100 > [] ? put_lock_stats.isra.25+0xe/0x40 > [] ? kthread_create_on_node+0x160/0x160 > [] ret_from_fork+0x7c/0xb0 > [] ? kthread_create_on_node+0x160/0x160 > > =============================== > [ INFO: suspicious RCU usage. ] > 3.7.0-rc1+ #31 Not tainted > ------------------------------- > include/linux/rcupdate.h:738 rcu_read_lock() used illegally while idle! > > other info that might help us debug this: > > > RCU used illegally from idle CPU! > rcu_scheduler_active = 1, debug_locks = 1 > RCU used illegally from extended quiescent state! > 4 locks on stack by migration/2/24: > #0: held: (&rq->lock){-.-.-.}, instance: ffff8801481d4a98, at: [] active_load_balance_cpu_stop+0x328/0x490 > #1: held: (&rq->lock/1){..-.-.}, instance: ffff8801483d4a98, at: [] active_load_balance_cpu_stop+0x339/0x490 > #2: blocked: (rcu_read_lock){.+.+..}, instance: ffffffff81c34e80, at: [] active_load_balance_cpu_stop+0xf4/0x490 > #3: blocked: (rcu_read_lock){.+.+..}, instance: ffffffff81c34e80, at: [] cpuacct_charge+0x13/0x230 > > stack backtrace: > Pid: 24, comm: migration/2 Not tainted 3.7.0-rc1+ #31 > Call Trace: > [] lockdep_rcu_suspicious+0xe2/0x130 > [] cpuacct_charge+0x1cc/0x230 > [] ? cpuacct_charge+0x13/0x230 > [] update_curr+0x104/0x270 > [] enqueue_entity+0x44/0x720 > [] enqueue_task_fair+0x42/0xf0 > [] enqueue_task+0x66/0x80 > [] activate_task+0x23/0x30 > [] move_task+0x3c/0x50 > [] active_load_balance_cpu_stop+0x282/0x490 > [] ? active_load_balance_cpu_stop+0xf4/0x490 > [] ? cpu_stopper_thread+0xb3/0x1d0 > [] ? select_task_rq_fair+0xad0/0xad0 > [] cpu_stopper_thread+0xdb/0x1d0 > [] ? sub_preempt_count+0x79/0xd0 > [] ? __schedule+0x499/0xa40 > [] ? cpu_stop_queue_work+0x80/0x80 > [] kthread+0xed/0x100 > [] ? put_lock_stats.isra.25+0xe/0x40 > [] ? kthread_create_on_node+0x160/0x160 > [] ret_from_fork+0x7c/0xb0 > [] ? kthread_create_on_node+0x160/0x160 > > =============================== > [ INFO: suspicious RCU usage. ] > 3.7.0-rc1+ #31 Not tainted > ------------------------------- > include/linux/cgroup.h:566 suspicious rcu_dereference_check() usage! > > other info that might help us debug this: > > > RCU used illegally from idle CPU! > rcu_scheduler_active = 1, debug_locks = 1 > RCU used illegally from extended quiescent state! > 4 locks on stack by migration/2/24: > #0: held: (&rq->lock){-.-.-.}, instance: ffff8801481d4a98, at: [] active_load_balance_cpu_stop+0x328/0x490 > #1: held: (&rq->lock/1){..-.-.}, instance: ffff8801483d4a98, at: [] active_load_balance_cpu_stop+0x339/0x490 > #2: blocked: (rcu_read_lock){.+.+..}, instance: ffffffff81c34e80, at: [] active_load_balance_cpu_stop+0xf4/0x490 > #3: blocked: (rcu_read_lock){.+.+..}, instance: ffffffff81c34e80, at: [] cpuacct_charge+0x13/0x230 > > stack backtrace: > Pid: 24, comm: migration/2 Not tainted 3.7.0-rc1+ #31 > Call Trace: > [] lockdep_rcu_suspicious+0xe2/0x130 > [] cpuacct_charge+0x195/0x230 > [] ? cpuacct_charge+0x13/0x230 > [] update_curr+0x104/0x270 > [] enqueue_entity+0x44/0x720 > [] enqueue_task_fair+0x42/0xf0 > [] enqueue_task+0x66/0x80 > [] activate_task+0x23/0x30 > [] move_task+0x3c/0x50 > [] active_load_balance_cpu_stop+0x282/0x490 > [] ? active_load_balance_cpu_stop+0xf4/0x490 > [] ? cpu_stopper_thread+0xb3/0x1d0 > [] ? select_task_rq_fair+0xad0/0xad0 > [] cpu_stopper_thread+0xdb/0x1d0 > [] ? sub_preempt_count+0x79/0xd0 > [] ? __schedule+0x499/0xa40 > [] ? cpu_stop_queue_work+0x80/0x80 > [] kthread+0xed/0x100 > [] ? put_lock_stats.isra.25+0xe/0x40 > [] ? kthread_create_on_node+0x160/0x160 > [] ret_from_fork+0x7c/0xb0 > [] ? kthread_create_on_node+0x160/0x160 > > =============================== > [ INFO: suspicious RCU usage. ] > 3.7.0-rc1+ #31 Not tainted > ------------------------------- > include/linux/rcupdate.h:759 rcu_read_unlock() used illegally while idle! > > other info that might help us debug this: > > > RCU used illegally from idle CPU! > rcu_scheduler_active = 1, debug_locks = 1 > RCU used illegally from extended quiescent state! > 4 locks on stack by migration/2/24: > #0: held: (&rq->lock){-.-.-.}, instance: ffff8801481d4a98, at: [] active_load_balance_cpu_stop+0x328/0x490 > #1: held: (&rq->lock/1){..-.-.}, instance: ffff8801483d4a98, at: [] active_load_balance_cpu_stop+0x339/0x490 > #2: blocked: (rcu_read_lock){.+.+..}, instance: ffffffff81c34e80, at: [] active_load_balance_cpu_stop+0xf4/0x490 > #3: blocked: (rcu_read_lock){.+.+..}, instance: ffffffff81c34e80, at: [] cpuacct_charge+0x13/0x230 > > stack backtrace: > Pid: 24, comm: migration/2 Not tainted 3.7.0-rc1+ #31 > Call Trace: > [] lockdep_rcu_suspicious+0xe2/0x130 > [] cpuacct_charge+0x130/0x230 > [] ? cpuacct_charge+0x13/0x230 > [] update_curr+0x104/0x270 > [] enqueue_entity+0x44/0x720 > [] enqueue_task_fair+0x42/0xf0 > [] enqueue_task+0x66/0x80 > [] activate_task+0x23/0x30 > [] move_task+0x3c/0x50 > [] active_load_balance_cpu_stop+0x282/0x490 > [] ? active_load_balance_cpu_stop+0xf4/0x490 > [] ? cpu_stopper_thread+0xb3/0x1d0 > [] ? select_task_rq_fair+0xad0/0xad0 > [] cpu_stopper_thread+0xdb/0x1d0 > [] ? sub_preempt_count+0x79/0xd0 > [] ? __schedule+0x499/0xa40 > [] ? cpu_stop_queue_work+0x80/0x80 > [] kthread+0xed/0x100 > [] ? put_lock_stats.isra.25+0xe/0x40 > [] ? kthread_create_on_node+0x160/0x160 > [] ret_from_fork+0x7c/0xb0 > [] ? kthread_create_on_node+0x160/0x160 > > =============================== > [ INFO: suspicious RCU usage. ] > 3.7.0-rc1+ #31 Not tainted > ------------------------------- > include/linux/rcupdate.h:759 rcu_read_unlock() used illegally while idle! > > other info that might help us debug this: > > > RCU used illegally from idle CPU! > rcu_scheduler_active = 1, debug_locks = 1 > RCU used illegally from extended quiescent state! > 3 locks on stack by migration/2/24: > #0: held: (&rq->lock){-.-.-.}, instance: ffff8801481d4a98, at: [] active_load_balance_cpu_stop+0x328/0x490 > #1: held: (&rq->lock/1){..-.-.}, instance: ffff8801483d4a98, at: [] active_load_balance_cpu_stop+0x339/0x490 > #2: blocked: (rcu_read_lock){.+.+..}, instance: ffffffff81c34e80, at: [] active_load_balance_cpu_stop+0xf4/0x490 > > stack backtrace: > Pid: 24, comm: migration/2 Not tainted 3.7.0-rc1+ #31 > Call Trace: > [] lockdep_rcu_suspicious+0xe2/0x130 > [] active_load_balance_cpu_stop+0x3e5/0x490 > [] ? active_load_balance_cpu_stop+0xf4/0x490 > [] ? cpu_stopper_thread+0xb3/0x1d0 > [] ? select_task_rq_fair+0xad0/0xad0 > [] cpu_stopper_thread+0xdb/0x1d0 > [] ? sub_preempt_count+0x79/0xd0 > [] ? __schedule+0x499/0xa40 > [] ? cpu_stop_queue_work+0x80/0x80 > [] kthread+0xed/0x100 > [] ? put_lock_stats.isra.25+0xe/0x40 > [] ? kthread_create_on_node+0x160/0x160 > [] ret_from_fork+0x7c/0xb0 > [] ? kthread_create_on_node+0x160/0x160 > > > =============================== > [ INFO: suspicious RCU usage. ] > 3.7.0-rc1+ #31 Not tainted > ------------------------------- > kernel/rcutree.c:360 Illegal idle entry in RCU read-side critical section.! > > other info that might help us debug this: > > > RCU used illegally from idle CPU! > rcu_scheduler_active = 1, debug_locks = 1 > RCU used illegally from extended quiescent state! > 1 lock on stack by rcuc/2/22: > #0: blocked: (rcu_read_lock){.+.+..}, instance: ffffffff81c34e80, at: [] __atomic_notifier_call_chain+0x5/0x140 > > stack backtrace: > Pid: 22, comm: rcuc/2 Not tainted 3.7.0-rc1+ #31 > Call Trace: > [] lockdep_rcu_suspicious+0xe2/0x130 > [] rcu_eqs_enter_common.isra.41+0x1b3/0x1f0 > [] rcu_irq_exit+0xbd/0x100 > [] irq_exit+0x8b/0xe0 > [] smp_apic_timer_interrupt+0x6b/0x98 > [] apic_timer_interrupt+0x72/0x80 > [] ? mark_held_locks+0xb2/0x130 > [] ? vprintk_emit+0x1b5/0x600 > [] printk+0x61/0x63 > [] lockdep_rcu_suspicious+0x2f/0x130 > [] __atomic_notifier_call_chain+0x12c/0x140 > [] ? __atomic_notifier_call_chain+0x5/0x140 > [] atomic_notifier_call_chain+0x16/0x20 > [] profile_handoff_task+0x1a/0x30 > [] __put_task_struct+0x88/0x140 > [] delayed_put_task_struct+0x48/0x170 > [] rcu_do_batch.isra.22+0x15a/0x440 > [] rcu_cpu_kthread+0x143/0x670 > [] smpboot_thread_fn+0x1d4/0x300 > [] ? __smpboot_create_thread.part.2+0xc0/0xc0 > [] kthread+0xed/0x100 > [] ? wait_for_common+0x135/0x180 > [] ? kthread_create_on_node+0x160/0x160 > [] ret_from_fork+0x7c/0xb0 > [] ? kthread_create_on_node+0x160/0x160 > =============================== > [ INFO: suspicious RCU usage. ] > 3.7.0-rc1+ #31 Not tainted > ------------------------------- > include/linux/rcupdate.h:738 rcu_read_lock() used illegally while idle! > > other info that might help us debug this: > > > RCU used illegally from idle CPU! > rcu_scheduler_active = 1, debug_locks = 1 > RCU used illegally from extended quiescent state! > 1 lock on stack by rcuc/2/22: > #0: blocked: (rcu_read_lock){.+.+..}, instance: ffffffff81c34e80, at: [] __atomic_notifier_call_chain+0x5/0x140 > > stack backtrace: > Pid: 22, comm: rcuc/2 Not tainted 3.7.0-rc1+ #31 > Call Trace: > [] lockdep_rcu_suspicious+0xe2/0x130 > [] __atomic_notifier_call_chain+0x12c/0x140 > [] ? __atomic_notifier_call_chain+0x5/0x140 > [] atomic_notifier_call_chain+0x16/0x20 > [] profile_handoff_task+0x1a/0x30 > [] __put_task_struct+0x88/0x140 > [] delayed_put_task_struct+0x48/0x170 > [] rcu_do_batch.isra.22+0x15a/0x440 > [] rcu_cpu_kthread+0x143/0x670 > [] smpboot_thread_fn+0x1d4/0x300 > [] ? __smpboot_create_thread.part.2+0xc0/0xc0 > [] kthread+0xed/0x100 > [] ? wait_for_common+0x135/0x180 > [] ? kthread_create_on_node+0x160/0x160 > [] ret_from_fork+0x7c/0xb0 > [] ? kthread_create_on_node+0x160/0x160 > > =============================== > [ INFO: suspicious RCU usage. ] > 3.7.0-rc1+ #31 Not tainted > ------------------------------- > include/linux/rcupdate.h:759 rcu_read_unlock() used illegally while idle! > > other info that might help us debug this: > > > RCU used illegally from idle CPU! > rcu_scheduler_active = 1, debug_locks = 1 > RCU used illegally from extended quiescent state! > 1 lock on stack by rcuc/2/22: > #0: blocked: (rcu_read_lock){.+.+..}, instance: ffffffff81c34e80, at: [] __atomic_notifier_call_chain+0x5/0x140 > > stack backtrace: > Pid: 22, comm: rcuc/2 Not tainted 3.7.0-rc1+ #31 > Call Trace: > [] lockdep_rcu_suspicious+0xe2/0x130 > [] __atomic_notifier_call_chain+0xf8/0x140 > [] ? __atomic_notifier_call_chain+0x5/0x140 > [] atomic_notifier_call_chain+0x16/0x20 > [] profile_handoff_task+0x1a/0x30 > [] __put_task_struct+0x88/0x140 > [] delayed_put_task_struct+0x48/0x170 > [] rcu_do_batch.isra.22+0x15a/0x440 > [] rcu_cpu_kthread+0x143/0x670 > [] smpboot_thread_fn+0x1d4/0x300 > [] ? __smpboot_create_thread.part.2+0xc0/0xc0 > [] kthread+0xed/0x100 > [] ? wait_for_common+0x135/0x180 > [] ? kthread_create_on_node+0x160/0x160 > [] ret_from_fork+0x7c/0xb0 > [] ? kthread_create_on_node+0x160/0x160 > > =============================== > [ INFO: suspicious RCU usage. ] > 3.7.0-rc1+ #31 Not tainted > ------------------------------- > kernel/sched/fair.c:4723 suspicious rcu_dereference_check() usage! > > other info that might help us debug this: > > > RCU used illegally from idle CPU! > rcu_scheduler_active = 1, debug_locks = 1 > RCU used illegally from extended quiescent state! > 1 lock on stack by rcuc/2/22: > #0: blocked: (rcu_read_lock){.+.+..}, instance: ffffffff81c34e80, at: [] rebalance_domains+0x5/0x310 > > stack backtrace: > Pid: 22, comm: rcuc/2 Not tainted 3.7.0-rc1+ #31 > Call Trace: > [] lockdep_rcu_suspicious+0xe2/0x130 > [] rebalance_domains+0x2e5/0x310 > [] ? rebalance_domains+0x5/0x310 > [] ? trace_hardirqs_on_caller+0x86/0x1e0 > [] run_rebalance_domains+0x4d/0x1c0 > [] ? dn_neigh_elist+0x40/0x160 [decnet] > [] __do_softirq+0xf0/0x440 > [] call_softirq+0x1c/0x30 > [] do_softirq+0xd5/0x110 > [] ? rcu_cpu_kthread+0x148/0x670 > [] local_bh_enable+0x11b/0x160 > [] rcu_cpu_kthread+0x148/0x670 > [] smpboot_thread_fn+0x1d4/0x300 > [] ? __smpboot_create_thread.part.2+0xc0/0xc0 > [] kthread+0xed/0x100 > [] ? wait_for_common+0x135/0x180 > [] ? kthread_create_on_node+0x160/0x160 > [] ret_from_fork+0x7c/0xb0 > [] ? kthread_create_on_node+0x160/0x160 > > =============================== > [ INFO: suspicious RCU usage. ] > 3.7.0-rc1+ #31 Not tainted > ------------------------------- > kernel/sched/fair.c:2715 suspicious rcu_dereference_check() usage! > > other info that might help us debug this: > > > RCU used illegally from idle CPU! > rcu_scheduler_active = 1, debug_locks = 1 > RCU used illegally from extended quiescent state! > 5 locks on stack by kworker/2:0/9822: > #0: blocked: (events){.+.+.+}, instance: ffff880147814fd8, at: [] process_one_work+0x197/0x780 > #1: blocked: ((&barr->work)){+.+...}, instance: ffff880083ad5d38, at: [] process_one_work+0x197/0x780 > #2: held: (&x->wait#8){......}, instance: ffff88005a183e90, at: [] complete+0x28/0x60 > #3: held: (&p->pi_lock){-.-.-.}, instance: ffff88003606cf78, at: [] try_to_wake_up+0x31/0x320 > #4: blocked: (rcu_read_lock){.+.+..}, instance: ffffffff81c34e80, at: [] select_task_rq_fair+0x61/0xad0 > > stack backtrace: > Pid: 9822, comm: kworker/2:0 Not tainted 3.7.0-rc1+ #31 > Call Trace: > [] lockdep_rcu_suspicious+0xe2/0x130 > [] select_task_rq_fair+0x3b0/0xad0 > [] ? select_task_rq_fair+0x61/0xad0 > [] ? put_lock_stats.isra.25+0xe/0x40 > [] ? try_to_wake_up+0x31/0x320 > [] try_to_wake_up+0xbe/0x320 > [] default_wake_function+0x12/0x20 > [] __wake_up_common+0x55/0x90 > [] ? complete+0x28/0x60 > [] complete+0x47/0x60 > [] wq_barrier_func+0x12/0x20 > [] process_one_work+0x207/0x780 > [] ? process_one_work+0x197/0x780 > [] ? destroy_work_on_stack+0x20/0x20 > [] process_scheduled_works+0x2c/0x40 > [] worker_thread+0x2fa/0x440 > [] ? rescuer_thread+0x240/0x240 > [] kthread+0xed/0x100 > [] ? put_lock_stats.isra.25+0xe/0x40 > [] ? kthread_create_on_node+0x160/0x160 > [] ret_from_fork+0x7c/0xb0 > [] ? kthread_create_on_node+0x160/0x160 > > =============================== > [ INFO: suspicious RCU usage. ] > 3.7.0-rc1+ #31 Not tainted > ------------------------------- > kernel/sched/core.c:1216 suspicious rcu_dereference_check() usage! > > other info that might help us debug this: > > > RCU used illegally from idle CPU! > rcu_scheduler_active = 1, debug_locks = 1 > RCU used illegally from extended quiescent state! > 5 locks on stack by kworker/2:0/9822: > #0: blocked: (events){.+.+.+}, instance: ffff880147814fd8, at: [] process_one_work+0x197/0x780 > #1: blocked: ((&barr->work)){+.+...}, instance: ffff880083ad5d38, at: [] process_one_work+0x197/0x780 > #2: held: (&x->wait#8){......}, instance: ffff88005a183e90, at: [] complete+0x28/0x60 > #3: held: (&p->pi_lock){-.-.-.}, instance: ffff88003606cf78, at: [] try_to_wake_up+0x31/0x320 > #4: blocked: (rcu_read_lock){.+.+..}, instance: ffffffff81c34e80, at: [] ttwu_stat+0x49/0x280 > > stack backtrace: > Pid: 9822, comm: kworker/2:0 Not tainted 3.7.0-rc1+ #31 > Call Trace: > [] lockdep_rcu_suspicious+0xe2/0x130 > [] ttwu_stat+0xfc/0x280 > [] ? ttwu_stat+0x49/0x280 > [] try_to_wake_up+0x190/0x320 > [] default_wake_function+0x12/0x20 > [] __wake_up_common+0x55/0x90 > [] ? complete+0x28/0x60 > [] complete+0x47/0x60 > [] wq_barrier_func+0x12/0x20 > [] process_one_work+0x207/0x780 > [] ? process_one_work+0x197/0x780 > [] ? destroy_work_on_stack+0x20/0x20 > [] process_scheduled_works+0x2c/0x40 > [] worker_thread+0x2fa/0x440 > [] ? rescuer_thread+0x240/0x240 > [] kthread+0xed/0x100 > [] ? put_lock_stats.isra.25+0xe/0x40 > [] ? kthread_create_on_node+0x160/0x160 > [] ret_from_fork+0x7c/0xb0 > [] ? kthread_create_on_node+0x160/0x160 > > =============================== > [ INFO: suspicious RCU usage. ] > 3.7.0-rc1+ #31 Not tainted > ------------------------------- > include/linux/rcupdate.h:738 rcu_read_lock() used illegally while idle! > > other info that might help us debug this: > > > RCU used illegally from idle CPU! > rcu_scheduler_active = 1, debug_locks = 1 > RCU used illegally from extended quiescent state! > 2 locks on stack by trinity-main/9791: > #0: held: (tasklist_lock){.+.+..}, instance: ffffffff81c05098, at: [] ptrace_stop+0xc1/0x280 > #1: blocked: (rcu_read_lock){.+.+..}, instance: ffffffff81c34e80, at: [] do_notify_parent_cldstop+0x2e/0x550 > > stack backtrace: > Pid: 9791, comm: trinity-main Not tainted 3.7.0-rc1+ #31 > Call Trace: > [] lockdep_rcu_suspicious+0xe2/0x130 > [] do_notify_parent_cldstop+0x3c5/0x550 > [] ? do_notify_parent_cldstop+0x2e/0x550 > [] ? put_lock_stats.isra.25+0xe/0x40 > [] ptrace_stop+0xfa/0x280 > [] ? __task_pid_nr_ns+0x5/0x1a0 > [] ptrace_do_notify+0x97/0xb0 > [] ptrace_notify+0x64/0x90 > [] tracehook_report_syscall_exit+0x36/0xb0 > [] ? finish_task_switch+0x7c/0x120 > [] ? int_very_careful+0x5/0xd > [] syscall_trace_leave+0x79/0x150 > [] int_check_syscall_exit_work+0x34/0x3d > > =============================== > [ INFO: suspicious RCU usage. ] > 3.7.0-rc1+ #31 Not tainted > ------------------------------- > kernel/signal.c:1756 suspicious rcu_dereference_check() usage! > > other info that might help us debug this: > > > RCU used illegally from idle CPU! > rcu_scheduler_active = 1, debug_locks = 1 > RCU used illegally from extended quiescent state! > 3 locks on stack by trinity-main/9791: > #0: held: (tasklist_lock){.+.+..}, instance: ffffffff81c05098, at: [] ptrace_stop+0xc1/0x280 > #1: blocked: (rcu_read_lock){.+.+..}, instance: ffffffff81c34e80, at: [] do_notify_parent_cldstop+0x2e/0x550 > #2: blocked: (rcu_read_lock){.+.+..}, instance: ffffffff81c34e80, at: [] do_notify_parent_cldstop+0x83/0x550 > > stack backtrace: > Pid: 9791, comm: trinity-main Not tainted 3.7.0-rc1+ #31 > Call Trace: > [] lockdep_rcu_suspicious+0xe2/0x130 > [] do_notify_parent_cldstop+0x4b8/0x550 > [] ? do_notify_parent_cldstop+0x83/0x550 > [] ? put_lock_stats.isra.25+0xe/0x40 > [] ptrace_stop+0xfa/0x280 > [] ? __task_pid_nr_ns+0x5/0x1a0 > [] ptrace_do_notify+0x97/0xb0 > [] ptrace_notify+0x64/0x90 > [] tracehook_report_syscall_exit+0x36/0xb0 > [] ? finish_task_switch+0x7c/0x120 > [] ? int_very_careful+0x5/0xd > [] syscall_trace_leave+0x79/0x150 > [] int_check_syscall_exit_work+0x34/0x3d > > =============================== > [ INFO: suspicious RCU usage. ] > 3.7.0-rc1+ #31 Not tainted > ------------------------------- > include/linux/rcupdate.h:759 rcu_read_unlock() used illegally while idle! > > other info that might help us debug this: > > > RCU used illegally from idle CPU! > rcu_scheduler_active = 1, debug_locks = 1 > RCU used illegally from extended quiescent state! > 3 locks on stack by trinity-main/9791: > #0: held: (tasklist_lock){.+.+..}, instance: ffffffff81c05098, at: [] ptrace_stop+0xc1/0x280 > #1: blocked: (rcu_read_lock){.+.+..}, instance: ffffffff81c34e80, at: [] do_notify_parent_cldstop+0x2e/0x550 > #2: blocked: (rcu_read_lock){.+.+..}, instance: ffffffff81c34e80, at: [] do_notify_parent_cldstop+0x83/0x550 > > stack backtrace: > Pid: 9791, comm: trinity-main Not tainted 3.7.0-rc1+ #31 > Call Trace: > [] lockdep_rcu_suspicious+0xe2/0x130 > [] do_notify_parent_cldstop+0x355/0x550 > [] ? do_notify_parent_cldstop+0x83/0x550 > [] ? put_lock_stats.isra.25+0xe/0x40 > [] ptrace_stop+0xfa/0x280 > [] ? __task_pid_nr_ns+0x5/0x1a0 > [] ptrace_do_notify+0x97/0xb0 > [] ptrace_notify+0x64/0x90 > [] tracehook_report_syscall_exit+0x36/0xb0 > [] ? finish_task_switch+0x7c/0x120 > [] ? int_very_careful+0x5/0xd > [] syscall_trace_leave+0x79/0x150 > [] int_check_syscall_exit_work+0x34/0x3d > > =============================== > [ INFO: suspicious RCU usage. ] > 3.7.0-rc1+ #31 Not tainted > ------------------------------- > kernel/signal.c:1756 suspicious rcu_dereference_check() usage! > > other info that might help us debug this: > > > RCU used illegally from idle CPU! > rcu_scheduler_active = 1, debug_locks = 1 > RCU used illegally from extended quiescent state! > 3 locks on stack by trinity-main/9791: > #0: held: (tasklist_lock){.+.+..}, instance: ffffffff81c05098, at: [] ptrace_stop+0xc1/0x280 > #1: blocked: (rcu_read_lock){.+.+..}, instance: ffffffff81c34e80, at: [] do_notify_parent_cldstop+0x2e/0x550 > #2: blocked: (rcu_read_lock){.+.+..}, instance: ffffffff81c34e80, at: [] do_notify_parent_cldstop+0x117/0x550 > > stack backtrace: > Pid: 9791, comm: trinity-main Not tainted 3.7.0-rc1+ #31 > Call Trace: > [] lockdep_rcu_suspicious+0xe2/0x130 > [] do_notify_parent_cldstop+0x4f8/0x550 > [] ? do_notify_parent_cldstop+0x117/0x550 > [] ? put_lock_stats.isra.25+0xe/0x40 > [] ptrace_stop+0xfa/0x280 > [] ? __task_pid_nr_ns+0x5/0x1a0 > [] ptrace_do_notify+0x97/0xb0 > [] ptrace_notify+0x64/0x90 > [] tracehook_report_syscall_exit+0x36/0xb0 > [] ? finish_task_switch+0x7c/0x120 > [] ? int_very_careful+0x5/0xd > [] syscall_trace_leave+0x79/0x150 > [] int_check_syscall_exit_work+0x34/0x3d > > =============================== > [ INFO: suspicious RCU usage. ] > 3.7.0-rc1+ #31 Not tainted > ------------------------------- > kernel/sched/fair.c:2660 suspicious rcu_dereference_check() usage! > > other info that might help us debug this: > > > RCU used illegally from idle CPU! > rcu_scheduler_active = 1, debug_locks = 1 > RCU used illegally from extended quiescent state! > 5 locks on stack by trinity-main/9791: > #0: held: (tasklist_lock){.+.+..}, instance: ffffffff81c05098, at: [] ptrace_stop+0xc1/0x280 > #1: held: (&(&sighand->siglock)->rlock){-.-.-.}, instance: ffff880107520820, at: [] do_notify_parent_cldstop+0x3f6/0x550 > #2: held: (&sig->wait_chldexit){......}, instance: ffff880035679528, at: [] __wake_up_sync_key+0x37/0x80 > #3: held: (&p->pi_lock){-.-.-.}, instance: ffff880035738658, at: [] try_to_wake_up+0x31/0x320 > #4: blocked: (rcu_read_lock){.+.+..}, instance: ffffffff81c34e80, at: [] select_task_rq_fair+0x61/0xad0 > > stack backtrace: > Pid: 9791, comm: trinity-main Not tainted 3.7.0-rc1+ #31 > Call Trace: > [] lockdep_rcu_suspicious+0xe2/0x130 > [] select_task_rq_fair+0x9ac/0xad0 > [] ? select_task_rq_fair+0x61/0xad0 > [] ? put_lock_stats.isra.25+0x29/0x40 > [] ? try_to_wake_up+0x31/0x320 > [] try_to_wake_up+0xbe/0x320 > [] default_wake_function+0x12/0x20 > [] child_wait_callback+0x5a/0x60 > [] __wake_up_common+0x55/0x90 > [] ? __wake_up_sync_key+0x37/0x80 > [] __wake_up_sync_key+0x53/0x80 > [] __wake_up_parent+0x26/0x30 > [] do_notify_parent_cldstop+0x42e/0x550 > [] ? do_notify_parent_cldstop+0x117/0x550 > [