Re: [PATCH] siganl: ignore other signals when doing coredump

From: Oleg Nesterov
Date: Mon Aug 03 2020 - 15:17:38 EST


On 07/31, chunlei.wang wrote:
>
> Please tell us much more about why you think Linux would benefit from
> this change. Precisely what operational problems are you seeing with
> the current code?
> =>
> Sorry for the late reply.
>
> If coredump is incomplete, R&D can not find root cause through
> coredump.
> If the issue is seldom, this modification will speed up the process of
> solving the problem.

To be honest, I do not even know what can I say, except that I disagree
with this change. The very idea looks wrong to me.

Granted, SIGKILL can kill the process which does something useful. Say,
dumps a core. So what?

Where does this SIGKILL come from? How often does this happen?

And why do you think the core dumping is special? Say, you try to debug
the buggy application, but a sudden SIGKILL kills the debuggee and you
lose the debugging session. Does this mean that the kernel needs another
patch to protect the process running under gdb from SIGKILL?

I don't think so. Please feel free to resend this patch, but it needs
a very convincing changelog. And please send it to lkml.

Oleg.