From: Dave Jones <davej@redhat.com>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Linux Kernel <linux-kernel@vger.kernel.org>
Subject: perf lockdep trace.
Date: Sat, 29 Mar 2014 11:15:03 -0400 [thread overview]
Message-ID: <20140329151503.GA14249@redhat.com> (raw)
Back home, and back to breaking things..
======================================================
[ INFO: possible circular locking dependency detected ]
3.14.0-rc8+ #153 Not tainted
-------------------------------------------------------
trinity-c3/2014 is trying to acquire lock:
(&rq->lock){-.-.-.}, at: [<ffffffff9a0bf75c>] unregister_fair_sched_group+0x5c/0xd0
but task is already holding lock:
(&ctx->lock){-.....}, at: [<ffffffff9a173fe9>] perf_event_exit_task+0x109/0x260
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (&ctx->lock){-.....}:
[<ffffffff9a0d1951>] lock_acquire+0x91/0x1c0
[<ffffffff9a7b3bf0>] _raw_spin_lock+0x40/0x80
[<ffffffff9a16f8fc>] __perf_event_task_sched_out+0x11c/0x3c0
[<ffffffff9a0a7b93>] perf_event_task_sched_out+0xb3/0xc0
[<ffffffff9a7ae2d4>] __schedule+0x1e4/0x9c0
[<ffffffff9a7af01e>] schedule_user+0x2e/0xa0
[<ffffffff9a7b4da4>] retint_careful+0x12/0x2e
-> #0 (&rq->lock){-.-.-.}:
[<ffffffff9a0d0dee>] __lock_acquire+0x181e/0x1bd0
[<ffffffff9a0d1951>] lock_acquire+0x91/0x1c0
[<ffffffff9a7b3dfb>] _raw_spin_lock_irqsave+0x4b/0x90
[<ffffffff9a0bf75c>] unregister_fair_sched_group+0x5c/0xd0
[<ffffffff9a0b3cfa>] sched_offline_group+0x3a/0xe0
[<ffffffff9a0c6cc7>] sched_autogroup_exit+0x47/0x60
[<ffffffff9a06b6a9>] __put_task_struct+0xb9/0x130
[<ffffffff9a169c45>] put_ctx+0x55/0x60
[<ffffffff9a17400e>] perf_event_exit_task+0x12e/0x260
[<ffffffff9a07022d>] do_exit+0x33d/0xd40
[<ffffffff9a07207c>] do_group_exit+0x4c/0xc0
[<ffffffff9a072104>] SyS_exit_group+0x14/0x20
[<ffffffff9a7bda64>] tracesys+0xdd/0xe2
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&ctx->lock);
lock(&rq->lock);
lock(&ctx->lock);
lock(&rq->lock);
*** DEADLOCK ***
1 lock held by trinity-c3/2014:
#0: (&ctx->lock){-.....}, at: [<ffffffff9a173fe9>] perf_event_exit_task+0x109/0x260
stack backtrace:
CPU: 3 PID: 2014 Comm: trinity-c3 Not tainted 3.14.0-rc8+ #153
ffffffff9b5efc70 00000000128a256a ffff88009ce09c08 ffffffff9a7a8da2
ffffffff9b5efc70 ffff88009ce09c48 ffffffff9a7a4e66 ffff88009ce09ca0
ffff88023ec94180 0000000000000000 ffff88023ec94148 ffff88023ec94180
Call Trace:
[<ffffffff9a7a8da2>] dump_stack+0x4e/0x7a
[<ffffffff9a7a4e66>] print_circular_bug+0x201/0x20f
[<ffffffff9a0d0dee>] __lock_acquire+0x181e/0x1bd0
[<ffffffff9a7a7119>] ? cmpxchg_double_slab.isra.57+0xdb/0x116
[<ffffffff9a0d1951>] lock_acquire+0x91/0x1c0
[<ffffffff9a0bf75c>] ? unregister_fair_sched_group+0x5c/0xd0
[<ffffffff9a7b3dfb>] _raw_spin_lock_irqsave+0x4b/0x90
[<ffffffff9a0bf75c>] ? unregister_fair_sched_group+0x5c/0xd0
[<ffffffff9a0bf75c>] unregister_fair_sched_group+0x5c/0xd0
[<ffffffff9a0b3cfa>] sched_offline_group+0x3a/0xe0
[<ffffffff9a0c6cc7>] sched_autogroup_exit+0x47/0x60
[<ffffffff9a06b6a9>] __put_task_struct+0xb9/0x130
[<ffffffff9a169c45>] put_ctx+0x55/0x60
[<ffffffff9a17400e>] perf_event_exit_task+0x12e/0x260
[<ffffffff9a7b8e0b>] ? preempt_count_sub+0x6b/0xf0
[<ffffffff9a07022d>] do_exit+0x33d/0xd40
[<ffffffff9a07207c>] do_group_exit+0x4c/0xc0
[<ffffffff9a072104>] SyS_exit_group+0x14/0x20
[<ffffffff9a7bda64>] tracesys+0xdd/0xe2
reply other threads:[~2014-03-29 15:15 UTC|newest]
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