Commit d11d31fc authored by Pavel Begunkov's avatar Pavel Begunkov
Browse files

io_uring: fix races with buffer table unregister 



Fixed buffer table quiesce might unlock ->uring_lock, potentially
letting new requests to be submitted, don't allow those requests to
use the table as they will race with unregistration.

Reported-and-tested-by: default avatarvan fantasy <g1042620637@gmail.com>
Fixes: bd54b6fe ("io_uring: implement fixed buffers registration similar to fixed files")
Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
parent b0380bf6

fs/io_uring.c

+7 −0
Original line number Diff line number Diff line
@@ -10680,12 +10680,19 @@ static void __io_sqe_buffers_unregister(struct io_ring_ctx *ctx) 


static int io_sqe_buffers_unregister(struct io_ring_ctx *ctx)

{

	unsigned nr = ctx->nr_user_bufs;

	int ret;



	if (!ctx->buf_data)

		return -ENXIO;



	/*

	 * Quiesce may unlock ->uring_lock, and while it's not held

	 * prevent new requests using the table.

	 */

	ctx->nr_user_bufs = 0;

	ret = io_rsrc_ref_quiesce(ctx->buf_data, ctx);

	ctx->nr_user_bufs = nr;

	if (!ret)

		__io_sqe_buffers_unregister(ctx);

	return ret;