From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E142924CEEA; Sat, 12 Sep 2026 09:32:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789205566; cv=none; b=cUTnEjbLJ9K8WE1V/xzg9nDQJNySN0CXC6mJGXxDsDsybiWjfEKiCL6hTwJgtBeP9DJCcnBZBQJ1RxgX+BO13IZmg78VqkJeSKbyzG4BD0fM4LEoy6xfe2NwWmFVksfJdPzjobSa/pfk1Q734tJeDoKcMN/3lVjZUdPs+KBuc5k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789205566; c=relaxed/simple; bh=Nc16eve/yL7p1Hu3BMTh1i/oaOezPxrlLDKAdqujQD4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=hQffG5AEDd6X84PXlt8U7CuTLvsdvMe+IkjSRmtuBKfgg8cASYXqf3gr6cY7KCJUQyhM3D+KUA4gK9ghrAt2CDkwR9sWHyN9qOet7gr/U8oOr2VkTmMOIequzCh2MUOnhb6R27NNoFJVuAtYkSTKh/krksLrz9TJW60GuTm3cmU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=RZvfml1m; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="RZvfml1m" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C7D641F000FF; Sat, 12 Sep 2026 09:32:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789205564; bh=wPnOxF0up865q+mwhFVzJJEPa2NnOYC/YI1IcKNxvG4=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=RZvfml1m0POjxZKUQKVaG2SrCHl2om4xBUU2fs5ALGgG+0vdSLTykzybH21DnUp8f cBY4JkLkDB+POcbdEfibyjwno8EzmvaZnnvsnYOn6Ci9Xjl6wRV4ZO+5zQ3oXhTljg 3Bkgn1X7QVc6eBcJt2VRnTjKq423NsOP9+4HtCoE= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jens Axboe , Sasha Levin Subject: [PATCH 6.18 0028/1518] io_uring: unify task_work cancelation checks Date: Sat, 12 Sep 2026 08:36:37 +0200 Message-ID: <20260912065624.060161612@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065623.398859879@linuxfoundation.org> References: <20260912065623.398859879@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jens Axboe [ Upstream commit 7be20254a743be4f02414b9d56cc3fe5f84e6500 ] Rather than do per-tw checking, which needs to dip into the task_struct for checking flags, do it upfront before running task_work. This places a 'cancel' member in io_tw_token_t, which is assigned before running task_work for that given ctx. This is both more efficient in doing it upfront rather than for every task_work, and it means that io_should_terminate_tw() can be made private in io_uring.c rather than need to be called by various callbacks of task_work. Signed-off-by: Jens Axboe Stable-dep-of: 14572de82e50 ("io_uring/waitid: honor task_work cancellation") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- include/linux/io_uring_types.h | 1 + io_uring/io_uring.c | 27 ++++++++++++++++++++------- io_uring/io_uring.h | 13 ------------- io_uring/poll.c | 2 +- io_uring/timeout.c | 2 +- io_uring/uring_cmd.c | 2 +- 6 files changed, 24 insertions(+), 23 deletions(-) --- a/include/linux/io_uring_types.h +++ b/include/linux/io_uring_types.h @@ -482,6 +482,7 @@ struct io_ring_ctx { * ONLY core io_uring.c should instantiate this struct. */ struct io_tw_state { + bool cancel; }; /* Alias to use in code that doesn't instantiate struct io_tw_state */ typedef struct io_tw_state io_tw_token_t; --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -268,6 +268,20 @@ static __cold void io_ring_ctx_ref_free( complete(&ctx->ref_comp); } +/* + * Terminate the request if either of these conditions are true: + * + * 1) It's being executed by the original task, but that task is marked + * with PF_EXITING as it's exiting. + * 2) PF_KTHREAD is set, in which case the invoker of the task_work is + * our fallback task_work. + * 3) The ring has been closed and is going away. + */ +static inline bool io_should_terminate_tw(struct io_ring_ctx *ctx) +{ + return (current->flags & (PF_EXITING | PF_KTHREAD)) || percpu_ref_is_dying(&ctx->refs); +} + static __cold void io_fallback_req_func(struct work_struct *work) { struct io_ring_ctx *ctx = container_of(work, struct io_ring_ctx, @@ -278,8 +292,10 @@ static __cold void io_fallback_req_func( percpu_ref_get(&ctx->refs); mutex_lock(&ctx->uring_lock); - llist_for_each_entry_safe(req, tmp, node, io_task_work.node) + llist_for_each_entry_safe(req, tmp, node, io_task_work.node) { + ts.cancel = io_should_terminate_tw(req->ctx); req->io_task_work.func(req, ts); + } io_submit_flush_completions(ctx); mutex_unlock(&ctx->uring_lock); percpu_ref_put(&ctx->refs); @@ -1152,6 +1168,7 @@ struct llist_node *io_handle_tw_list(str ctx = req->ctx; mutex_lock(&ctx->uring_lock); percpu_ref_get(&ctx->refs); + ts.cancel = io_should_terminate_tw(ctx); } INDIRECT_CALL_2(req->io_task_work.func, io_poll_task_func, io_req_rw_complete, @@ -1210,11 +1227,6 @@ struct llist_node *tctx_task_work_run(st { struct llist_node *node; - if (unlikely(current->flags & PF_EXITING)) { - io_fallback_tw(tctx, true); - return NULL; - } - node = llist_del_all(&tctx->task_list); if (node) { node = llist_reverse_order(node); @@ -1432,6 +1444,7 @@ static int __io_run_local_work(struct io if (ctx->flags & IORING_SETUP_TASKRUN_FLAG) atomic_andnot(IORING_SQ_TASKRUN, &ctx->rings->sq_flags); again: + tw.cancel = io_should_terminate_tw(ctx); min_events -= ret; ret = __io_run_local_work_loop(&ctx->retry_llist.first, tw, max_events); if (ctx->retry_llist.first) @@ -1491,7 +1504,7 @@ void io_req_task_submit(struct io_kiocb struct io_ring_ctx *ctx = req->ctx; io_tw_lock(ctx, tw); - if (unlikely(io_should_terminate_tw(ctx))) + if (unlikely(tw.cancel)) io_req_defer_failed(req, -EFAULT); else if (req->flags & REQ_F_FORCE_ASYNC) io_queue_iowq(req); --- a/io_uring/io_uring.h +++ b/io_uring/io_uring.h @@ -582,19 +582,6 @@ static inline bool io_allowed_run_tw(str ctx->submitter_task == current); } -/* - * Terminate the request if either of these conditions are true: - * - * 1) It's being executed by the original task, but that task is marked - * with PF_EXITING as it's exiting. - * 2) PF_KTHREAD is set, in which case the invoker of the task_work is - * our fallback task_work. - */ -static inline bool io_should_terminate_tw(struct io_ring_ctx *ctx) -{ - return (current->flags & (PF_KTHREAD | PF_EXITING)) || percpu_ref_is_dying(&ctx->refs); -} - static inline void io_req_queue_tw_complete(struct io_kiocb *req, s32 res) { io_req_set_res(req, res, 0); --- a/io_uring/poll.c +++ b/io_uring/poll.c @@ -225,7 +225,7 @@ static int io_poll_check_events(struct i { int v; - if (unlikely(io_should_terminate_tw(req->ctx))) + if (unlikely(tw.cancel)) return -ECANCELED; do { --- a/io_uring/timeout.c +++ b/io_uring/timeout.c @@ -324,7 +324,7 @@ static void io_req_task_link_timeout(str int ret; if (prev) { - if (!io_should_terminate_tw(req->ctx)) { + if (!tw.cancel) { struct io_cancel_data cd = { .ctx = req->ctx, .data = prev->cqe.user_data, --- a/io_uring/uring_cmd.c +++ b/io_uring/uring_cmd.c @@ -120,7 +120,7 @@ static void io_uring_cmd_work(struct io_ struct io_uring_cmd *ioucmd = io_kiocb_to_cmd(req, struct io_uring_cmd); unsigned int flags = IO_URING_F_COMPLETE_DEFER; - if (io_should_terminate_tw(req->ctx)) + if (unlikely(tw.cancel)) flags |= IO_URING_F_TASK_DEAD; /* task_work executor checks the deffered list completion */