Commit 3539b146 authored by Jens Axboe's avatar Jens Axboe
Browse files

io_uring: include dying ring in task_work "should cancel" state 

When running task_work for an exiting task, rather than perform the
issue retry attempt, the task_work is canceled. However, this isn't
done for a ring that has been closed. This can lead to requests being
successfully completed post the ring being closed, which is somewhat
confusing and surprising to an application.

Rather than just check the task exit state, also include the ring
ref state in deciding whether or not to terminate a given request when
run from task_work.

Cc: stable@vger.kernel.org # 6.1+
Link: https://github.com/axboe/liburing/discussions/1459


Reported-by: default avatarBenedek Thaler <thaler@thaler.hu>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent cd4ea81b

io_uring/io_uring.c

+4 −2
Original line number Diff line number Diff line
@@ -1406,8 +1406,10 @@ static void io_req_task_cancel(struct io_kiocb *req, io_tw_token_t tw) 


void io_req_task_submit(struct io_kiocb *req, io_tw_token_t tw)

{

	io_tw_lock(req->ctx, tw);

	if (unlikely(io_should_terminate_tw()))

	struct io_ring_ctx *ctx = req->ctx;



	io_tw_lock(ctx, tw);

	if (unlikely(io_should_terminate_tw(ctx)))

		io_req_defer_failed(req, -EFAULT);

	else if (req->flags & REQ_F_FORCE_ASYNC)

		io_queue_iowq(req);

io_uring/io_uring.h

+2 −2
Original line number Diff line number Diff line
@@ -476,9 +476,9 @@ static inline bool io_allowed_run_tw(struct io_ring_ctx *ctx) 
 * 2) PF_KTHREAD is set, in which case the invoker of the task_work is

 *    our fallback task_work.

 */

static inline bool io_should_terminate_tw(void)

static inline bool io_should_terminate_tw(struct io_ring_ctx *ctx)

{

	return current->flags & (PF_KTHREAD | PF_EXITING);

	return (current->flags & (PF_KTHREAD | PF_EXITING)) || percpu_ref_is_dying(&ctx->refs);

}



static inline void io_req_queue_tw_complete(struct io_kiocb *req, s32 res)

io_uring/poll.c

+1 −1
Original line number Diff line number Diff line
@@ -224,7 +224,7 @@ static int io_poll_check_events(struct io_kiocb *req, io_tw_token_t tw) 
{

	int v;



	if (unlikely(io_should_terminate_tw()))

	if (unlikely(io_should_terminate_tw(req->ctx)))

		return -ECANCELED;



	do {

io_uring/timeout.c

+1 −1
Original line number Diff line number Diff line
@@ -324,7 +324,7 @@ static void io_req_task_link_timeout(struct io_kiocb *req, io_tw_token_t tw) 
	int ret;



	if (prev) {

		if (!io_should_terminate_tw()) {

		if (!io_should_terminate_tw(req->ctx)) {

			struct io_cancel_data cd = {

				.ctx		= req->ctx,

				.data		= prev->cqe.user_data,

io_uring/uring_cmd.c

+1 −1
Original line number Diff line number Diff line
@@ -118,7 +118,7 @@ static void io_uring_cmd_work(struct io_kiocb *req, io_tw_token_t tw) 
	struct io_uring_cmd *ioucmd = io_kiocb_to_cmd(req, struct io_uring_cmd);

	unsigned int flags = IO_URING_F_COMPLETE_DEFER;



	if (io_should_terminate_tw())

	if (io_should_terminate_tw(req->ctx))

		flags |= IO_URING_F_TASK_DEAD;



	/* task_work executor checks the deffered list completion */