Messages in this thread | | | Date | Tue, 6 Jan 2009 19:32:07 +0530 | From | Vaidyanathan Srinivasan <> | Subject | Re: [BUG] 2.6.28-git LOCKDEP: Possible recursive rq->lock |
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* Ingo Molnar <mingo@elte.hu> [2009-01-05 14:06:38]:
> > * Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> wrote: > > > * Peter Zijlstra <a.p.zijlstra@chello.nl> [2009-01-04 19:08:43]: > > > > > On Sun, 2009-01-04 at 23:14 +0530, Vaidyanathan Srinivasan wrote: > > > > Hi Ingo, > > > > > > > > Kernbench runs on latest Linux git tree stalled with the following > > > > lockdep warning. > > > > > > > > Lockdep warning and lockup on Jan 3 Linus git tree > > > > commit 7d3b56ba37a95f1f370f50258ed3954c304c524b > > > > > > > > kernbench run with two threads stalled. sched_mc was zero. > > > > x86_64 system with 8 logical CPUs in dual socket quad core > > > > configuration. > > > > > > > > I will post more information as I debug this warning/bug. > > > > > > Its ca109491f612aab5c8152207631c0444f63da97f, I've some ideas on how to > > > fix this, just haven't gotten around to actually doing anything -- > > > seeing how it was holidays and such.. > > > > Hi Peter, > > > > I can definitely test your fix when you have them. I have an > > autotest job that hits this bug. > > could you check latest tip/master, it has Peter's and Thomas's hrtimer > fixes.
Hi Peter,
I queued the same kernbench runs with the latest tip. The run completed without any lockups, but I still got one lockdep warning.
sched-tip date Jan 5 commit:4c1ae1dfea7a5fcab3444220a38054dd50c08441
kernel: ============================================= kernel: [ INFO: possible recursive locking detected ] kernel: 2.6.28-autotest-tip-sv #1 kernel: --------------------------------------------- kernel: autotest/6012 is trying to acquire lock: kernel: (&rq->lock){++..}, at: [<ffffffff8022a4dd>] task_rq_lock+0x44/0x7e kernel: kernel: but task is already holding lock: kernel: (&rq->lock){++..}, at: [<ffffffff805d6000>] schedule+0x144/0x9e5 kernel: kernel: other info that might help us debug this: kernel: 1 lock held by autotest/6012: kernel: #0: (&rq->lock){++..}, at: [<ffffffff805d6000>] schedule+0x144/0x9e5 kernel: kernel: stack backtrace: kernel: Pid: 6012, comm: autotest Not tainted 2.6.28-autotest-tip-sv #1 kernel: Call Trace: kernel: [<ffffffff80257a0c>] __lock_acquire+0xe2a/0x15ed kernel: [<ffffffff80258254>] lock_acquire+0x85/0xa9 kernel: [<ffffffff8022a4dd>] task_rq_lock+0x44/0x7e kernel: [<ffffffff805d8fac>] _spin_lock+0x2d/0x5f kernel: [<ffffffff8022a4dd>] task_rq_lock+0x44/0x7e kernel: [<ffffffff8022a4dd>] task_rq_lock+0x44/0x7e kernel: [<ffffffff80232947>] try_to_wake_up+0x83/0x26f kernel: [<ffffffff805d6000>] schedule+0x144/0x9e5 kernel: [<ffffffff805d6415>] schedule+0x559/0x9e5 kernel: [<ffffffff802562fc>] trace_hardirqs_on_caller+0x120/0x14a kernel: [<ffffffff8024b721>] hrtimer_start_range_ns+0x1e4/0x1f7 kernel: [<ffffffff805d7bda>] schedule_hrtimeout_range+0xcc/0xff kernel: [<ffffffff8024af3d>] hrtimer_wakeup+0x0/0x22 kernel: [<ffffffff805d7bbc>] schedule_hrtimeout_range+0xae/0xff kernel: [<ffffffff802ae194>] do_select+0x502/0x55d kernel: [<ffffffff802adc92>] do_select+0x0/0x55d kernel: [<ffffffff802ae70b>] __pollwait+0x0/0xe5 kernel: [<ffffffff80232b33>] default_wake_function+0x0/0x9 kernel: [<ffffffff80232b33>] default_wake_function+0x0/0x9 kernel: [<ffffffff80254211>] lock_release_holdtime+0x1b/0x16c kernel: [<ffffffff802581b6>] __lock_acquire+0x15d4/0x15ed last message repeated 2 times kernel: [<ffffffff80254211>] lock_release_holdtime+0x1b/0x16c kernel: [<ffffffff80254211>] lock_release_holdtime+0x1b/0x16c kernel: [<ffffffff802ae220>] core_sys_select+0x31/0x2b0 kernel: [<ffffffff802ae3db>] core_sys_select+0x1ec/0x2b0 kernel: [<ffffffff802ae220>] core_sys_select+0x31/0x2b0 kernel: [<ffffffff80248d47>] remove_wait_queue+0x12/0x4d kernel: [<ffffffff80254211>] lock_release_holdtime+0x1b/0x16c kernel: [<ffffffff805d8e29>] _spin_unlock_irqrestore+0x3e/0x44 kernel: [<ffffffff802562fc>] trace_hardirqs_on_caller+0x120/0x14a kernel: [<ffffffff8023909b>] do_wait+0x2a4/0x395 kernel: [<ffffffff8024ec91>] getnstimeofday+0x56/0xb0 kernel: [<ffffffff802ae6e2>] sys_select+0x92/0xbb kernel: [<ffffffff8020bedb>] system_call_fastpath+0x16/0x1b
I will rerun and check again.
--Vaidy
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