Re: [PATCH] swap_readpage: avoid blk_wake_io_task() if !synchronous

[Andrew Morton]

On Thu, 4 Jul 2019 18:03:01 +0200 Oleg Nesterov <o...@redhat.com> wrote:

> swap_readpage() sets waiter = bio->bi_private even if synchronous = F,
> this means that the caller can get the spurious wakeup after return. This
> can be fatal if blk_wake_io_task() does set_current_state(TASK_RUNNING)
> after the caller does set_special_state(), in the worst case the kernel
> can crash in do_task_dead().

I think we need a Fixes: and a cc:stable here?

IIRC, we're fixing 0619317ff8baa2 ("block: add polled wakeup task helper").