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Subject: Re: [PATCH -next v2] riscv: add VMAP_STACK overflow detection
To:     Jisheng Zhang <jszhang3@mail.ustc.edu.cn>,
        Andreas Schwab <schwab@linux-m68k.org>
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CC:     Atish Patra <atishp@atishpatra.org>,
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From:   tongtiangen <tongtiangen@huawei.com>
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Date:   Fri, 23 Jul 2021 09:36:47 +0800
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On 2021/7/23 7:54, Jisheng Zhang wrote:
> On Thu, 22 Jul 2021 17:42:52 +0200
> Andreas Schwab <schwab@linux-m68k.org> wrote:
>
>> On Jul 22 2021, Jisheng Zhang wrote:
>>
>>> I think we need to pin the stack before calling get_wchan(), could you please
>>> try below patch?
>>
>> Thanks, this fixes the crash for me.
>>
>> Andreas.
>>
>
> Thanks for testing. I will send out formal patch later
>
> Thanks
>
> .
>

Hi all:
I tried to reproduced this crash in openSUSE code repo（ 
https://github.com/opensuse/kernel ）, but not reproduced successfully.

 From the patch of problem repair, the crash is due to task->stack is 
released before calling get_wchan, the task state of maybe TASK_DEAD.

VMAP_STACK is used to detect kernel stack overflow, there is no 
connection between the two, it makes me a little confused.