From 6567506b68b0cae3934f1a58b35d709f38fc2e90 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Thu, 8 Sep 2022 16:56:53 +0100 Subject: [PATCH] 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: c0e0d6ba25f1 ("io_uring: add IORING_SETUP_DEFER_TASKRUN") Signed-off-by: Pavel Begunkov Reviewed-by: Dylan Yudaken Link: https://lore.kernel.org/r/b4f0d3f14236d7059d08c5abe2661ef0b78b5528.1662652536.git.asml.silence@gmail.com Signed-off-by: Jens Axboe --- io_uring/io_uring.c | 7 +------ io_uring/io_uring.h | 9 ++------- 2 files changed, 3 insertions(+), 13 deletions(-) diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index e95877398b57..39dda1b7a600 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -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; diff --git a/io_uring/io_uring.h b/io_uring/io_uring.h index 4eea0836170e..d38173b9ac19 100644 --- a/io_uring/io_uring.h +++ b/io_uring/io_uring.h @@ -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 -- 2.25.1