Re: [patch 07/44] posix-cpu-timers: Simplify sighand locking in run_posix_cpu_timers()

From: Frederic Weisbecker
Date: Wed Aug 21 2019 - 08:09:22 EST

On Mon, Aug 19, 2019 at 04:31:48PM +0200, Thomas Gleixner wrote:
> run_posix_cpu_timers() is called from the timer interrupt. The posix timer
> expiry always affects the current task which got interrupted.
> sighand locking is only racy when done on a foreign task, which must use
> lock_task_sighand(). But in case of run_posix_cpu_timers() that's
> pointless.
> sighand of a task can only be dropped or changed by the task itself. Drop
> happens in do_exit()

Well, that's only in case of autoreap. Otherwise this is dropped by the reaper.

> changing sighand happens in execve().