From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6133AC4708E for ; Sat, 29 May 2021 13:48:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3A6C2610C7 for ; Sat, 29 May 2021 13:48:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229762AbhE2Nuc (ORCPT ); Sat, 29 May 2021 09:50:32 -0400 Received: from forward1-smtp.messagingengine.com ([66.111.4.223]:53855 "EHLO forward1-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229681AbhE2Nuc (ORCPT ); Sat, 29 May 2021 09:50:32 -0400 Received: from compute4.internal (compute4.nyi.internal [10.202.2.44]) by mailforward.nyi.internal (Postfix) with ESMTP id 8DA221941038; Sat, 29 May 2021 09:48:55 -0400 (EDT) Received: from mailfrontend2 ([10.202.2.163]) by compute4.internal (MEProxy); Sat, 29 May 2021 09:48:55 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-transfer-encoding:content-type :date:from:message-id:mime-version:subject:to:x-me-proxy :x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm2; bh=7m05fZ OcFEvK6TNyBSz0pqK5MpUGKrjJ27j9kQgeCHs=; b=dLRBei9asJ0mIkfGviAqf0 166xRdVvaVl+I7hMPhHAMgh0P04KRCMGurJVjsPdSmqlX4y9FWd23i1kMUnPkMnc VvVBIt+LKaxv0g02+hJMHH/i1gL9mcDaMK7wYbnJmn9a/H5IWUdySty7GBo05A+8 idR3KU3AD/iaom0szmLAQpZ7ehOHORQIeRsJHNMcr5tVdAvzpAo8E5FAgzvw/TLu ku/Jm8RIkyjdZroAdbJOsNkbh9G9yaZ7wU7VGKyuhfloRIIiTnPrk3wKxjqxPOdK tGkE6T4fhyYmOBFbFjp9yDrRnEYuH9mF/4sYVDdgZ2BR8zlkIGxhigebLTfaEzQQ == X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeduledrvdekledgjedtucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucenucfjughrpefuvffhfffkgggtgfesthekredttd dtlfenucfhrhhomhepoehgrhgvghhkhheslhhinhhugihfohhunhgurghtihhonhdrohhr gheqnecuggftrfgrthhtvghrnhepleelledvgeefleeltdetgedugeffgffhudffudduke egfeelgeeigeekjefhleevnecuffhomhgrihhnpehkvghrnhgvlhdrohhrghenucfkphep keefrdekiedrjeegrdeigeenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhepmh grihhlfhhrohhmpehgrhgvgheskhhrohgrhhdrtghomh X-ME-Proxy: Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) by mail.messagingengine.com (Postfix) with ESMTPA; Sat, 29 May 2021 09:48:54 -0400 (EDT) Subject: FAILED: patch "[PATCH] io_uring/io-wq: close io-wq full-stop gap" failed to apply to 5.10-stable tree To: asml.silence@gmail.com, axboe@kernel.dk Cc: From: Date: Sat, 29 May 2021 15:48:44 +0200 Message-ID: <1622296124147105@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 17a91051fe63b40ec651b80097c9fff5b093fdc5 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Sun, 23 May 2021 15:48:39 +0100 Subject: [PATCH] io_uring/io-wq: close io-wq full-stop gap There is an old problem with io-wq cancellation where requests should be killed and are in io-wq but are not discoverable, e.g. in @next_hashed or @linked vars of io_worker_handle_work(). It adds some unreliability to individual request canellation, but also may potentially get __io_uring_cancel() stuck. For instance: 1) An __io_uring_cancel()'s cancellation round have not found any request but there are some as desribed. 2) __io_uring_cancel() goes to sleep 3) Then workers wake up and try to execute those hidden requests that happen to be unbound. As we already cancel all requests of io-wq there, set IO_WQ_BIT_EXIT in advance, so preventing 3) from executing unbound requests. The workers will initially break looping because of getting a signal as they are threads of the dying/exec()'ing user task. Cc: stable@vger.kernel.org Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/abfcf8c54cb9e8f7bfbad7e9a0cc5433cc70bdc2.1621781238.git.asml.silence@gmail.com Signed-off-by: Jens Axboe diff --git a/fs/io-wq.c b/fs/io-wq.c index 5361a9b4b47b..de9b7ba3ba01 100644 --- a/fs/io-wq.c +++ b/fs/io-wq.c @@ -979,13 +979,16 @@ static bool io_task_work_match(struct callback_head *cb, void *data) return cwd->wqe->wq == data; } +void io_wq_exit_start(struct io_wq *wq) +{ + set_bit(IO_WQ_BIT_EXIT, &wq->state); +} + static void io_wq_exit_workers(struct io_wq *wq) { struct callback_head *cb; int node; - set_bit(IO_WQ_BIT_EXIT, &wq->state); - if (!wq->task) return; @@ -1020,8 +1023,6 @@ static void io_wq_destroy(struct io_wq *wq) cpuhp_state_remove_instance_nocalls(io_wq_online, &wq->cpuhp_node); - io_wq_exit_workers(wq); - for_each_node(node) { struct io_wqe *wqe = wq->wqes[node]; struct io_cb_cancel_data match = { @@ -1036,16 +1037,13 @@ static void io_wq_destroy(struct io_wq *wq) kfree(wq); } -void io_wq_put(struct io_wq *wq) -{ - if (refcount_dec_and_test(&wq->refs)) - io_wq_destroy(wq); -} - void io_wq_put_and_exit(struct io_wq *wq) { + WARN_ON_ONCE(!test_bit(IO_WQ_BIT_EXIT, &wq->state)); + io_wq_exit_workers(wq); - io_wq_put(wq); + if (refcount_dec_and_test(&wq->refs)) + io_wq_destroy(wq); } static bool io_wq_worker_affinity(struct io_worker *worker, void *data) diff --git a/fs/io-wq.h b/fs/io-wq.h index 0e6d310999e8..af2df0680ee2 100644 --- a/fs/io-wq.h +++ b/fs/io-wq.h @@ -122,7 +122,7 @@ struct io_wq_data { }; struct io_wq *io_wq_create(unsigned bounded, struct io_wq_data *data); -void io_wq_put(struct io_wq *wq); +void io_wq_exit_start(struct io_wq *wq); void io_wq_put_and_exit(struct io_wq *wq); void io_wq_enqueue(struct io_wq *wq, struct io_wq_work *work); diff --git a/fs/io_uring.c b/fs/io_uring.c index 5f82954004f6..6af8ca0cb01c 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -9078,6 +9078,9 @@ static void io_uring_cancel_sqpoll(struct io_sq_data *sqd) if (!current->io_uring) return; + if (tctx->io_wq) + io_wq_exit_start(tctx->io_wq); + WARN_ON_ONCE(!sqd || sqd->thread != current); atomic_inc(&tctx->in_idle); @@ -9112,6 +9115,9 @@ void __io_uring_cancel(struct files_struct *files) DEFINE_WAIT(wait); s64 inflight; + if (tctx->io_wq) + io_wq_exit_start(tctx->io_wq); + /* make sure overflow events are dropped */ atomic_inc(&tctx->in_idle); do {