From: "Kohli, Gaurav" <gkohli@codeaurora.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: tglx@linutronix.de, mpe@ellerman.id.au, mingo@kernel.org,
bigeasy@linutronix.de, linux-kernel@vger.kernel.org,
linux-arm-msm@vger.kernel.org,
Neeraj Upadhyay <neeraju@codeaurora.org>,
Will Deacon <will.deacon@arm.com>,
Oleg Nesterov <oleg@redhat.com>
Subject: Re: [PATCH v1] kthread/smpboot: Serialize kthread parking against wakeup
Date: Tue, 5 Jun 2018 16:43:45 +0530 [thread overview]
Message-ID: <ba12bc49-33c0-b4ee-05cf-f84124bd66cc@codeaurora.org> (raw)
In-Reply-To: <55221a5b-dd52-3359-f582-86830dd9f205@codeaurora.org>
Hi Peter,
As last mentioned on mail, we are still seeing issue with the latest
approach and below is the susceptible race as mentioned earlier..
controller Thread CPUHP Thread
takedown_cpu
kthread_park
kthread_parkme
Set KTHREAD_SHOULD_PARK
smpboot_thread_fn
set Task interruptible
wake_up_process
if (!(p->state & state))
goto out;
Kthread_parkme
SET TASK_PARKED
schedule
raw_spin_lock(&rq->lock)
ttwu_remote
waiting for __task_rq_lock
context_switch
finish_lock_switch
Case TASK_PARKED
kthread_park_complete
SET Running
So it seems issue is still their with the latest mentioned fix
kthread, sched/wait: Fix kthread_parkme() completion issue.
Regards
Gaurav
On 5/7/2018 4:53 PM, Kohli, Gaurav wrote:
> Corrected the formatting, Sorry for spam.
>
>
>>
>> HI Peter,
>>
>> We have tested with new patch and still seeing same issue, in this
>> dumps we don't have debug traces, but seems there still exist race
>> from code review , Can you please check it once:
>>
>> Controller Thread CPUHP Thread
>> takedown_cpu
>> kthread_park
>> kthread_parkme
>> Set KTHREAD_SHOULD_PARK
>> smpboot_thread_fn
>> set Task interruptible
>>
>>
>> wake_up_process
>>
>> Kthread_parkme
>> SET TASK_PARKED
>> schedule
>> raw_spin_lock(&rq->lock)
>>
>> context_switch
>>
>> finish_lock_switch
>>
>>
>>
>> Case TASK_PARKED
>> kthread_park_complete
>>
>>
>> SET TASK_INTERRUPTIBLE
>>
>>
>> And also seeing the same warning during unpark of cpuhp from controller:
>> if (!wait_task_inactive(p, state)) {
>> WARN_ON(1);
>> return;
>> }
>> 325.065893] [<ffffff8920ed0200>] kthread_unpark+0x80/0xd8
>> [ 325.065902] [<ffffff8920eab754>] bringup_cpu+0xa0/0x12c
>> [ 325.065910] [<ffffff8920eaae90>] cpuhp_invoke_callback+0xb4/0x5c8
>> [ 325.065917] [<ffffff8920eabd98>] cpuhp_up_callbacks+0x3c/0x154
>> [ 325.065924] [<ffffff8920ead220>] _cpu_up+0x134/0x208
>> [ 325.065931] [<ffffff8920ead45c>] do_cpu_up+0x168/0x1a0
>> [ 325.065938] [<ffffff8920ead4b8>] cpu_up+0x24/0x30
>> [ 325.065948] [<ffffff89215b1408>] cpu_subsys_online+0x20/0x2c
>> [ 325.065956] [<ffffff89215aac64>] device_online+0x70/0xb4
>> [ 325.065962] [<ffffff89215aad78>] online_store+0xd0/0xdc
>> [ 325.065971] [<ffffff89215a7424>] dev_attr_store+0x40/0x54
>> [ 325.065982] [<ffffff89210d8a98>] sysfs_kf_write+0x5c/0x74
>> [ 325.065988] [<ffffff89210d7b9c>] kernfs_fop_write+0xcc/0x1ec
>> [ 325.065999] [<ffffff8921049288>] vfs_write+0xb4/0x1d0
>> [ 325.066006] [<ffffff892104a858>] SyS_write+0x60/0xc0
>> [ 325.066014] [<ffffff8920e83770>] el0_svc_naked+0x24/0x28
>>
>>
>> And after this same crash occured:
>> [ 325.521307] [<ffffff8920ed4aac>] smpboot_thread_fn+0x26c/0x2c8
>> [ 325.527295] [<ffffff8920ecfb24>] kthread+0xf4/0x108
>>
>> I will put more debug ftraces to check what is going on exactly.
>>
>> Regards
>> Gaurav
>>
>>
>>
>>
>
--
Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center,
Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project.
next prev parent reply other threads:[~2018-06-05 11:13 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-25 8:33 [PATCH v1] kthread/smpboot: Serialize kthread parking against wakeup Gaurav Kohli
2018-04-25 20:09 ` Peter Zijlstra
2018-04-26 4:04 ` Kohli, Gaurav
2018-04-26 9:14 ` Peter Zijlstra
2018-04-26 8:41 ` Peter Zijlstra
2018-04-26 8:57 ` Peter Zijlstra
2018-04-26 15:53 ` Kohli, Gaurav
2018-04-30 11:17 ` Peter Zijlstra
2018-05-01 7:50 ` Kohli, Gaurav
2018-05-01 10:18 ` Peter Zijlstra
2018-05-01 10:40 ` Peter Zijlstra
2018-05-01 10:40 ` Kohli, Gaurav
2018-05-01 11:31 ` Peter Zijlstra
2018-05-01 11:46 ` Kohli, Gaurav
2018-05-01 13:19 ` Peter Zijlstra
2018-05-02 5:15 ` Kohli, Gaurav
2018-05-02 8:20 ` Peter Zijlstra
2018-05-02 10:13 ` Kohli, Gaurav
2018-05-07 11:09 ` Kohli, Gaurav
2018-05-07 11:23 ` Kohli, Gaurav
2018-06-05 11:13 ` Kohli, Gaurav [this message]
2018-06-05 15:08 ` Oleg Nesterov
2018-06-05 15:22 ` Peter Zijlstra
2018-06-05 15:40 ` Peter Zijlstra
2018-06-05 16:35 ` Oleg Nesterov
2018-06-05 18:21 ` Kohli, Gaurav
2018-06-05 20:13 ` Peter Zijlstra
2018-06-06 13:51 ` Oleg Nesterov
2018-06-06 15:03 ` Peter Zijlstra
2018-06-06 15:04 ` Peter Zijlstra
2018-06-06 15:22 ` Peter Zijlstra
2018-06-06 18:59 ` Peter Zijlstra
2018-06-07 8:30 ` Kohli, Gaurav
2018-05-01 10:44 ` Peter Zijlstra
2018-04-26 16:02 ` Andrea Parri
2018-04-26 16:18 ` Oleg Nesterov
2018-04-30 11:20 ` Peter Zijlstra
2018-04-30 11:56 ` Peter Zijlstra
2018-04-28 6:43 ` [lkp-robot] [kthread/smpboot] cad8e99675: inconsistent{IN-HARDIRQ-W}->{HARDIRQ-ON-W}usage kernel test robot
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