Messages in this thread | | | Date | Tue, 30 Sep 2008 13:53:15 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH 2/6] Unified trace buffer |
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a third type of lockdep splat surfaced in -tip testing:
============================================= [ INFO: possible recursive locking detected ] 2.6.27-rc8-tip #37560 --------------------------------------------- swapper/0 is trying to acquire lock: (&cpu_buffer->lock){.+..}, at: [<ffffffff802906ac>] ring_buffer_lock+0x46/0x5e
but task is already holding lock: (&cpu_buffer->lock){.+..}, at: [<ffffffff802906ac>] ring_buffer_lock+0x46/0x5e
other info that might help us debug this: 2 locks held by swapper/0: #0: (&rq->lock){++..}, at: [<ffffffff80754540>] schedule+0x16f/0x839 #1: (&cpu_buffer->lock){.+..}, at: [<ffffffff802906ac>] ring_buffer_lock+0x46/0x5e
stack backtrace: Pid: 0, comm: swapper Not tainted 2.6.27-rc8-tip #37560 Call Trace: [<ffffffff802743b6>] __lock_acquire+0xb2a/0x116f [<ffffffff80274a88>] lock_acquire+0x8d/0xba [<ffffffff802906ac>] ring_buffer_lock+0x46/0x5e [<ffffffff80756b7c>] _spin_lock+0x29/0x34 [<ffffffff802906ac>] ring_buffer_lock+0x46/0x5e [<ffffffff8039d992>] __next_cpu+0x19/0x28 [<ffffffff802906ac>] ring_buffer_lock+0x46/0x5e [<ffffffff80290762>] ring_buffer_reset+0x1c/0x58 [<ffffffff802942b9>] update_max_tr+0x5f/0x7f [<ffffffff802954e0>] probe_wakeup_sched_switch+0x175/0x189 [<ffffffff80754aa8>] schedule+0x6d7/0x839 [<ffffffff80273de2>] __lock_acquire+0x556/0x116f [<ffffffff807567bb>] trace_hardirqs_on_thunk+0x3a/0x3f [<ffffffff802732c8>] trace_hardirqs_on_caller+0xb4/0xd7 [<ffffffff807567bb>] trace_hardirqs_on_thunk+0x3a/0x3f [<ffffffff80269ea4>] ktime_get_ts+0x21/0x4a [<ffffffff8026c44f>] getnstimeofday+0x38/0x98 [<ffffffff80269ea4>] ktime_get_ts+0x21/0x4a [<ffffffff80227fc8>] native_sched_clock+0x8c/0xa6 [<ffffffff8026b485>] sched_clock_tick+0x78/0x80 [<ffffffff8027020f>] tick_nohz_restart_sched_tick+0x16b/0x178 [<ffffffff802732c8>] trace_hardirqs_on_caller+0xb4/0xd7 [<ffffffff8021fd70>] cpu_idle+0x77/0x79 driver: '2-0:1.0': driver_bound: bound to device 'hub'
Ingo
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