Re: [PATCH] io_uring: fix __io_iopoll_check deadlock in io_sq_thread

[Jens Axboe <axboe@kernel.dk>]

On 2/21/20 11:46 PM, Xiaoguang Wang wrote:
> Since commit a3a0e43fd770 ("io_uring: don't enter poll loop if we have
> CQEs pending"), if we already events pending, we won't enter poll loop.
> In case SETUP_IOPOLL and SETUP_SQPOLL are both enabled, if app has
> been terminated and don't reap pengding events which are already in cq
> ring, and there are some reqs in poll_list, io_sq_thread will enter
> __io_iopoll_check(), and find pending events, then return, this loop
> will never have a chance to exit.
> 
> I have seem this issue in fio stress tests, to fix this issue, let
> io_sq_thread call io_iopoll_getevents() with argument 'min' being zero,
> and remove __io_iopoll_check().

Thanks, nice and clean fix. Applied for 5.6.

-- 
Jens Axboe