From: John Ogness <john.ogness@linutronix.de>
To: "Kohli, Gaurav" <gkohli@codeaurora.org>
Cc: peterz@infradead.org, mingo@kernel.org,
linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org
Subject: Re: Query: Crash is coming during /prod/PID/stat and do_exit of same task
Date: Mon, 15 Jan 2018 12:02:23 +0100 [thread overview]
Message-ID: <87zi5fxu4g.fsf@linutronix.de> (raw)
In-Reply-To: <36ea8b88-4786-dbb2-6b89-15f9801e9c86@codeaurora.org> (Gaurav Kohli's message of "Tue, 9 Jan 2018 19:03:05 +0530")
Hello Gaurav.
On 2018-01-09, Kohli, Gaurav <gkohli@codeaurora.org> wrote:
> We are seeing crash in do_task_stat while accessing stack pointer, It
> seems same task has already completed do_exit call.
> So it seems a race between them:
>
> Below is the crash trace:
> 49750.534377] Kernel BUG at ffffff8e7a4c53a8 [verbose debug info
> unavailable]
> [49750.534394] task: ffffffe7b4475580 task.stack: ffffffe7a5f0c000
> [49750.534400] PC is at do_task_stat+0x740/0x908
> [49750.534402] LR is at do_task_stat+0xa4/0x908
> [49750.534403] pc : [<ffffff8e7a4c53a8>] lr : [<ffffff8e7a4c4d0c>]
> pstate: 80400145
> [49750.534404] sp : ffffffe7a5f0fbd0
>
> and here is stack trace on that core:
>
> -000|user_stack_pointer(inline)
> -000|do_task_stat(
> | m = 0xFFFFFFE7A5CD7380,
> | ns = 0xFFFFFF8E7C43C748,
> | ?,
> | task = 0xFFFFFFE80D8C2280,
> | ?)
> | tty_pgrp = 0
> | ppid = 2084696064
> | sid = 0
> | mm = 0xFFFFFFE7B4424140
> | tcomm = (84, 9, 71, 122, 142, 255, 255, 255, 48, 253, 240, 165,
> 231, 255, 255, 255)
> | flags = 18446743969119403392
> -001|proc_tgid_stat(
> | m = 0xFFFFFFE7A5CD7380,
> | ?,
>
> Below are task stats which shows , process completed the do_exit call:
> struct task_struct.flags -x 0xFFFFFFE80D8C2280
> flags = 0x40870c
>
> crash_64> struct task_struct.exit_code -x 0xFFFFFFE80D8C2280
> exit_code = 0x6
>
> struct task_struct.state -x 0xFFFFFFE80D8C2280
> state = 0x40
I am confused why this task is in the TASK_PARKED state. What kind of
task is this?
> In our build both patches are there ,
> fs/proc: report eip/esp in /prod/PID/stat for coredumping
>
> and also task.state has already set PF_DUMPCORE as it got the sigabrt
> signal.
John Ogness
WARNING: multiple messages have this Message-ID (diff)
From: John Ogness <john.ogness@linutronix.de>
To: "Kohli\, Gaurav" <gkohli@codeaurora.org>
Cc: peterz@infradead.org, mingo@kernel.org,
linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org
Subject: Re: Query: Crash is coming during /prod/PID/stat and do_exit of same task
Date: Mon, 15 Jan 2018 12:02:23 +0100 [thread overview]
Message-ID: <87zi5fxu4g.fsf@linutronix.de> (raw)
In-Reply-To: <36ea8b88-4786-dbb2-6b89-15f9801e9c86@codeaurora.org> (Gaurav Kohli's message of "Tue, 9 Jan 2018 19:03:05 +0530")
Hello Gaurav.
On 2018-01-09, Kohli, Gaurav <gkohli@codeaurora.org> wrote:
> We are seeing crash in do_task_stat while accessing stack pointer, It
> seems same task has already completed do_exit call.
> So it seems a race between them:
>
> Below is the crash trace:
> 49750.534377] Kernel BUG at ffffff8e7a4c53a8 [verbose debug info
> unavailable]
> [49750.534394] task: ffffffe7b4475580 task.stack: ffffffe7a5f0c000
> [49750.534400] PC is at do_task_stat+0x740/0x908
> [49750.534402] LR is at do_task_stat+0xa4/0x908
> [49750.534403] pc : [<ffffff8e7a4c53a8>] lr : [<ffffff8e7a4c4d0c>]
> pstate: 80400145
> [49750.534404] sp : ffffffe7a5f0fbd0
>
> and here is stack trace on that core:
>
> -000|user_stack_pointer(inline)
> -000|do_task_stat(
> | m = 0xFFFFFFE7A5CD7380,
> | ns = 0xFFFFFF8E7C43C748,
> | ?,
> | task = 0xFFFFFFE80D8C2280,
> | ?)
> | tty_pgrp = 0
> | ppid = 2084696064
> | sid = 0
> | mm = 0xFFFFFFE7B4424140
> | tcomm = (84, 9, 71, 122, 142, 255, 255, 255, 48, 253, 240, 165,
> 231, 255, 255, 255)
> | flags = 18446743969119403392
> -001|proc_tgid_stat(
> | m = 0xFFFFFFE7A5CD7380,
> | ?,
>
> Below are task stats which shows , process completed the do_exit call:
> struct task_struct.flags -x 0xFFFFFFE80D8C2280
> flags = 0x40870c
>
> crash_64> struct task_struct.exit_code -x 0xFFFFFFE80D8C2280
> exit_code = 0x6
>
> struct task_struct.state -x 0xFFFFFFE80D8C2280
> state = 0x40
I am confused why this task is in the TASK_PARKED state. What kind of
task is this?
> In our build both patches are there ,
> fs/proc: report eip/esp in /prod/PID/stat for coredumping
>
> and also task.state has already set PF_DUMPCORE as it got the sigabrt
> signal.
John Ogness
next prev parent reply other threads:[~2018-01-15 11:02 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-09 13:33 Query: Crash is coming during /prod/PID/stat and do_exit of same task Kohli, Gaurav
2018-01-15 10:04 ` Kohli, Gaurav
2018-01-15 11:02 ` John Ogness [this message]
2018-01-15 11:02 ` John Ogness
2018-01-15 12:30 ` Kohli, Gaurav
-- strict thread matches above, loose matches on Subject: below --
2018-01-10 5:20 Alexey Dobriyan
2018-01-16 5:36 ` Kohli, Gaurav
2018-01-16 7:20 ` Alexey Dobriyan
2018-01-16 9:44 ` Kohli, Gaurav
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