Re: [PATCH -next v2] riscv: add VMAP_STACK overflow detection

[tongtiangen]

On 2021/7/23 7:54, Jisheng Zhang wrote:
> On Thu, 22 Jul 2021 17:42:52 +0200
> Andreas Schwab <schwab@xxxxxxxxxxxxxx> 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.