Commit 44eff40a authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe
Browse files

io_uring: fix io_prep_async_link locking 



io_prep_async_link() may be called after arming a linked timeout,
automatically making it unsafe to traverse the linked list. Guard
with completion_lock if there was a linked timeout.

Cc: stable@vger.kernel.org # 5.9+
Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/93f7c617e2b4f012a2a175b3dab6bc2f27cebc48.1627304436.git.asml.silence@gmail.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 991468dc

fs/io_uring.c

+11 −2
Original line number Diff line number Diff line
@@ -1279,9 +1279,18 @@ static void io_prep_async_link(struct io_kiocb *req) 
{

	struct io_kiocb *cur;



	if (req->flags & REQ_F_LINK_TIMEOUT) {

		struct io_ring_ctx *ctx = req->ctx;



		spin_lock_irq(&ctx->completion_lock);

		io_for_each_link(cur, req)

			io_prep_async_work(cur);

		spin_unlock_irq(&ctx->completion_lock);

	} else {

		io_for_each_link(cur, req)

			io_prep_async_work(cur);

	}

}



static void io_queue_async_work(struct io_kiocb *req)

{