Commit a890d01e authored by Hao Xu's avatar Hao Xu Committed by Jens Axboe
Browse files

io_uring: fix poll requests leaking second poll entries 



For pure poll requests, it doesn't remove the second poll wait entry
when it's done, neither after vfs_poll() or in the poll completion
handler. We should remove the second poll wait entry.
And we use io_poll_remove_double() rather than io_poll_remove_waitqs()
since the latter has some redundant logic.

Fixes: 88e41cf9 ("io_uring: add multishot mode for IORING_OP_POLL_ADD")
Cc: stable@vger.kernel.org # 5.13+
Signed-off-by: default avatarHao Xu <haoxu@linux.alibaba.com>
Link: https://lore.kernel.org/r/20210728030322.12307-1-haoxu@linux.alibaba.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent ef046888

fs/io_uring.c

+2 −3
Original line number Diff line number Diff line
@@ -4939,7 +4939,6 @@ static bool io_poll_complete(struct io_kiocb *req, __poll_t mask) 
	if (req->poll.events & EPOLLONESHOT)

		flags = 0;

	if (!io_cqring_fill_event(ctx, req->user_data, error, flags)) {

		io_poll_remove_waitqs(req);

		req->poll.done = true;

		flags = 0;

	}
@@ -4962,6 +4961,7 @@ static void io_poll_task_func(struct io_kiocb *req) 


		done = io_poll_complete(req, req->result);

		if (done) {

			io_poll_remove_double(req);

			hash_del(&req->hash_node);

		} else {

			req->result = 0;
@@ -5149,7 +5149,7 @@ static __poll_t __io_arm_poll_handler(struct io_kiocb *req, 
		ipt->error = -EINVAL;



	spin_lock_irq(&ctx->completion_lock);

	if (ipt->error)

	if (ipt->error || (mask && (poll->events & EPOLLONESHOT)))

		io_poll_remove_double(req);

	if (likely(poll->head)) {

		spin_lock(&poll->head->lock);
@@ -5221,7 +5221,6 @@ static int io_arm_poll_handler(struct io_kiocb *req) 
	ret = __io_arm_poll_handler(req, &apoll->poll, &ipt, mask,

					io_async_wake);

	if (ret || ipt.error) {

		io_poll_remove_double(req);

		spin_unlock_irq(&ctx->completion_lock);

		if (ret)

			return IO_APOLL_READY;