Re: [PATCH 5.15] io_uring: fix ltimeout unprep

[Pavel Begunkov <asml.silence@gmail.com>]

On 10/20/21 09:33, Pavel Begunkov wrote:
> On 10/20/21 02:48, Jens Axboe wrote:
>> On 10/19/21 7:26 PM, Pavel Begunkov wrote:
>>> io_unprep_linked_timeout() is broken, first it needs to return back
>>> REQ_F_ARM_LTIMEOUT, so the linked timeout is enqueued and disarmed. But
>>> now we refcounted it, and linked timeouts may get not executed at all,
>>> leaking a request.
>>>
>>> Just kill the unprep optimisation.
>>
>> This appears to be against something that is not 5.15, can you please
>> check the end result:
> 
> Yeah, it was 5.16 for some reason. Looks good, thanks!

Actually, it's not. We need either unprep but "smarter" or queue the
timeout. I'll send a v2 for convenience, but a fold in is below.

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 36db7b76cf8d..d5cc103224f1 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -6979,6 +6979,8 @@ static void __io_queue_sqe(struct io_kiocb *req)
  
  		switch (io_arm_poll_handler(req)) {
  		case IO_APOLL_READY:
+			if (linked_timeout)
+				io_queue_linked_timeout(linked_timeout);
  			goto issue_sqe;
  		case IO_APOLL_ABORTED:
  			/*


-- 
Pavel Begunkov