Commit 6567506b authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe
Browse files

io_uring: disallow defer-tw run w/ no submitters 



We try to restrict CQ waiters when IORING_SETUP_DEFER_TASKRUN is set,
but if nothing has been submitted yet it'll allow any waiter, which
violates the contract.

Fixes: c0e0d6ba ("io_uring: add IORING_SETUP_DEFER_TASKRUN")
Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Reviewed-by: default avatarDylan Yudaken <dylany@fb.com>
Link: https://lore.kernel.org/r/b4f0d3f14236d7059d08c5abe2661ef0b78b5528.1662652536.git.asml.silence@gmail.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 76de6749

io_uring/io_uring.c

+1 −6
Original line number Diff line number Diff line
@@ -1169,13 +1169,8 @@ int __io_run_local_work(struct io_ring_ctx *ctx, bool locked) 
	int ret;

	unsigned int loops = 1;



	if (unlikely(ctx->submitter_task != current)) {

		/* maybe this is before any submissions */

		if (!ctx->submitter_task)

			return 0;



	if (unlikely(ctx->submitter_task != current))

		return -EEXIST;

	}



	node = io_llist_xchg(&ctx->work_llist, &fake);

	ret = 0;

io_uring/io_uring.h

+2 −7
Original line number Diff line number Diff line
@@ -331,13 +331,8 @@ static inline struct io_kiocb *io_alloc_req(struct io_ring_ctx *ctx) 


static inline bool io_allowed_run_tw(struct io_ring_ctx *ctx)

{

	if (!(ctx->flags & IORING_SETUP_DEFER_TASKRUN))

		return true;

	if (unlikely(ctx->submitter_task != current)) {

		/* maybe this is before any submissions */

		return !ctx->submitter_task;

	}

	return true;

	return likely(!(ctx->flags & IORING_SETUP_DEFER_TASKRUN) ||

		      ctx->submitter_task == current);

}



#endif