Re: wait_on_page_bit_common(TASK_KILLABLE, EXCLUSIVE) can miss wakeup?

[Oleg Nesterov]

On 06/24, Oleg Nesterov wrote:
> Suppose that 2 threads T1 and T2 call __lock_page_killable() and sleep in
> wait_on_page_bit_common() -> io_schedule().
>
> T1 is killed, it does test_and_set_bit_lock() but the page is still locked.
>
> unlock_page() calls __wake_up_common(nr_exclusive = 1), this wakes T1 up.
> T2 is not woken.

Ah, please ignore me, sorry for noise.

If T1 is killed it is TASK_RUNNING, try_to_wake_up() should return 0.

Oleg.