Re: [PATCH] posix-cpu-timers: don't abuse lock_task_sighand() in handle_posix_cpu_timers()

[Oleg Nesterov]

Hi Bradley,

FYI, this is another private message.

On 07/04, Bradley Morgan wrote:
>
> hi oleg! I'm new to reviewing, so feel free to criticize.

This is fine...

But if you want to have a "real" practice, you can try to review V2 from Eric:

	[PATCH v2 00/14] Short circuit delivery for coredump signals
	https://lore.kernel.org/all/877bnb4uyw.fsf_-_@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/

I won't be able to take a look until the middle of the next week.

> Would a WARN_ON_ONCE(tsk != current) be worth adding?

See my reply on lkml. But since this message is private...

IOW. tsk->sighand must be stable here or we have more problems. Without this
patch the "if (!lock_task_sighand(tsk, &flags))" check looks as if we can handle
the case were ->sighand is not stable, but this is not true.

And. This patch is trivial, but it connects to other (under discussion, nontrivial)
changes related to the wrong usage of lock_task_sighand() in posix-cpu-timers.c.

> For this patch,
>
> Reviewed-by: Bradley Morgan <include@xxxxxxxxx>

Thanks again,

Oleg.