Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755248Ab3JCTIs (ORCPT ); Thu, 3 Oct 2013 15:08:48 -0400 Received: from mx1.redhat.com ([209.132.183.28]:22608 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755163Ab3JCTIp (ORCPT ); Thu, 3 Oct 2013 15:08:45 -0400 Date: Thu, 3 Oct 2013 15:08:30 -0400 From: Dave Jones To: Linux Kernel Cc: a.p.zijlstra@chello.nl, gregkh@linuxfoundation.org, peter@hurleysoftware.com Subject: tty/perf lockdep trace. Message-ID: <20131003190830.GA18672@redhat.com> Mail-Followup-To: Dave Jones , Linux Kernel , a.p.zijlstra@chello.nl, gregkh@linuxfoundation.org, peter@hurleysoftware.com MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline 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: 5644 Lines: 128 ====================================================== [ INFO: possible circular locking dependency detected ] 3.12.0-rc3+ #92 Not tainted ------------------------------------------------------- trinity-child2/15191 is trying to acquire lock: (&rdp->nocb_wq){......}, at: [] __wake_up+0x23/0x50 but task is already holding lock: (&ctx->lock){-.-...}, at: [] perf_event_exit_task+0x109/0x230 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&ctx->lock){-.-...}: [] lock_acquire+0x93/0x200 [] _raw_spin_lock+0x40/0x80 [] __perf_event_task_sched_out+0x2df/0x5e0 [] perf_event_task_sched_out+0x93/0xa0 [] __schedule+0x1d2/0xa20 [] preempt_schedule_irq+0x50/0xb0 [] retint_kernel+0x26/0x30 [] tty_flip_buffer_push+0x34/0x50 [] pty_write+0x54/0x60 [] n_tty_write+0x32d/0x4e0 [] tty_write+0x158/0x2d0 [] vfs_write+0xc0/0x1f0 [] SyS_write+0x4c/0xa0 [] tracesys+0xdd/0xe2 -> #2 (&rq->lock){-.-.-.}: [] lock_acquire+0x93/0x200 [] _raw_spin_lock+0x40/0x80 [] wake_up_new_task+0xc2/0x2e0 [] do_fork+0x126/0x460 [] kernel_thread+0x26/0x30 [] rest_init+0x23/0x140 [] start_kernel+0x3f6/0x403 [] x86_64_start_reservations+0x2a/0x2c [] x86_64_start_kernel+0xf1/0xf4 -> #1 (&p->pi_lock){-.-.-.}: [] lock_acquire+0x93/0x200 [] _raw_spin_lock_irqsave+0x4b/0x90 [] try_to_wake_up+0x31/0x350 [] default_wake_function+0x12/0x20 [] autoremove_wake_function+0x18/0x40 [] __wake_up_common+0x58/0x90 [] __wake_up+0x39/0x50 [] __call_rcu_nocb_enqueue+0xa8/0xc0 [] __call_rcu+0x140/0x820 [] call_rcu+0x1d/0x20 [] cpu_attach_domain+0x287/0x360 [] build_sched_domains+0xe5e/0x10a0 [] sched_init_smp+0x3b7/0x47a [] kernel_init_freeable+0xf6/0x202 [] kernel_init+0xe/0x190 [] ret_from_fork+0x7c/0xb0 -> #0 (&rdp->nocb_wq){......}: [] __lock_acquire+0x191a/0x1be0 [] lock_acquire+0x93/0x200 [] _raw_spin_lock_irqsave+0x4b/0x90 [] __wake_up+0x23/0x50 [] __call_rcu_nocb_enqueue+0xa8/0xc0 [] __call_rcu+0x140/0x820 [] kfree_call_rcu+0x20/0x30 [] put_ctx+0x4f/0x70 [] perf_event_exit_task+0x12e/0x230 [] do_exit+0x30d/0xcc0 [] do_group_exit+0x4c/0xc0 [] SyS_exit_group+0x14/0x20 [] tracesys+0xdd/0xe2 other info that might help us debug this: Chain exists of: &rdp->nocb_wq --> &rq->lock --> &ctx->lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&ctx->lock); lock(&rq->lock); lock(&ctx->lock); lock(&rdp->nocb_wq); *** DEADLOCK *** 1 lock held by trinity-child2/15191: #0: (&ctx->lock){-.-...}, at: [] perf_event_exit_task+0x109/0x230 stack backtrace: CPU: 2 PID: 15191 Comm: trinity-child2 Not tainted 3.12.0-rc3+ #92 ffffffff82565b70 ffff880070c2dbf8 ffffffff8172a363 ffffffff824edf40 ffff880070c2dc38 ffffffff81726741 ffff880070c2dc90 ffff88022383b1c0 ffff88022383aac0 0000000000000000 ffff88022383b188 ffff88022383b1c0 Call Trace: [] dump_stack+0x4e/0x82 [] print_circular_bug+0x200/0x20f [] __lock_acquire+0x191a/0x1be0 [] ? get_lock_stats+0x19/0x60 [] ? native_sched_clock+0x24/0x80 [] lock_acquire+0x93/0x200 [] ? __wake_up+0x23/0x50 [] _raw_spin_lock_irqsave+0x4b/0x90 [] ? __wake_up+0x23/0x50 [] __wake_up+0x23/0x50 [] __call_rcu_nocb_enqueue+0xa8/0xc0 [] __call_rcu+0x140/0x820 [] ? local_clock+0x3f/0x50 [] kfree_call_rcu+0x20/0x30 [] put_ctx+0x4f/0x70 [] perf_event_exit_task+0x12e/0x230 [] do_exit+0x30d/0xcc0 [] ? trace_hardirqs_on_caller+0x115/0x1e0 [] ? trace_hardirqs_on+0xd/0x10 [] do_group_exit+0x4c/0xc0 [] SyS_exit_group+0x14/0x20 [] tracesys+0xdd/0xe2 -- 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/