io_uring: fix link lookup racing with link timeout (9a472ef7) · Commits · 戴 / test

We can't just go over linked requests because it may race with linked timeouts. Take ctx->completion_lock in that case. Cc: stable@vger.kernel.org # v5.7+ Signed-off-by:

Pavel Begunkov <asml.silence@gmail.com> Signed-off-by:

Jens Axboe <axboe@kernel.dk>

fs/io_uring.c

+15 −1

Original line number	Diff line number	Diff line
		@@ -8470,7 +8470,21 @@ static bool io_timeout_remove_link(struct io_ring_ctx *ctx,

		static bool io_cancel_link_cb(struct io_wq_work work, void data)
		{
		return io_match_link(container_of(work, struct io_kiocb, work), data);
		struct io_kiocb *req = container_of(work, struct io_kiocb, work);
		bool ret;

		if (req->flags & REQ_F_LINK_TIMEOUT) {
		unsigned long flags;
		struct io_ring_ctx *ctx = req->ctx;

		/* protect against races with linked timeouts */
		spin_lock_irqsave(&ctx->completion_lock, flags);
		ret = io_match_link(req, data);
		spin_unlock_irqrestore(&ctx->completion_lock, flags);
		} else {
		ret = io_match_link(req, data);
		}
		return ret;
		}

		static void io_attempt_cancel(struct io_ring_ctx ctx, struct io_kiocb req)

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