Re: [patch V4 part 1 29/36] x86/mce: Send #MC singal from task work

[Borislav Petkov]

On Thu, May 14, 2020 at 12:03:30PM -0400, Mathieu Desnoyers wrote:
> - #MC triggered, queuing task work,
> - unrelated signal happens to be delivered to task,
> - exit to usermode loop handles do_signal first,
> - then it runs task work.

How can that even happen?

exit_to_usermode_loop->do_signal->get_signal and that does:

        if (unlikely(current->task_works))
                task_work_run();

at the top.

So the task work will always run before the signal handler.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette