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 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 8BB85C49EAB for ; Sun, 27 Jun 2021 14:24:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 702EB61C29 for ; Sun, 27 Jun 2021 14:24:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231216AbhF0O0a (ORCPT ); Sun, 27 Jun 2021 10:26:30 -0400 Received: from forward1-smtp.messagingengine.com ([66.111.4.223]:34873 "EHLO forward1-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230288AbhF0O0a (ORCPT ); Sun, 27 Jun 2021 10:26:30 -0400 Received: from compute5.internal (compute5.nyi.internal [10.202.2.45]) by mailforward.nyi.internal (Postfix) with ESMTP id 281A21940629; Sun, 27 Jun 2021 10:24:06 -0400 (EDT) Received: from mailfrontend2 ([10.202.2.163]) by compute5.internal (MEProxy); Sun, 27 Jun 2021 10:24:06 -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=fm3; bh=bQGZTS xl04HeUA6S4AWxPtHz3Nm783yJ5tQFGt48ZhM=; b=sky/CIEN7Ifuz4gBDKlPT2 F+LRbQzuNy9LitJpM3pAukm4rtflyd+KCLX+o7bOct8pP1x1WB4f/AMj6lCxmLuU AyjnSfgbO/iYEvJMp2NZgYAkA31HmyG4oOyg6lgPTNsCo32gK1VzyVCpo0ZvrxV6 DdcHN3gwtvtL9jc+tmVtxoq3RR4l2dV7JPcaBcsAMrr6YyN/xD0zTEHtKQtYUoJu cq00xCNO404kfmQmW2Dv0AKyTdk/tPMnvbIKDcHn3MJQ0rM/o1K2u3sIJOvjY7ar yA/3nu9lv6N0qJaD5plO6S9wip7g3kF4vo9MEPFez4tgq1Hkb9eAYdO0s3cIulIw == X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeduledrfeehvddgjeeiucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucenucfjughrpefuvffhfffkgggtgfesthekredttd dtlfenucfhrhhomhepoehgrhgvghhkhheslhhinhhugihfohhunhgurghtihhonhdrohhr gheqnecuggftrfgrthhtvghrnhepleelledvgeefleeltdetgedugeffgffhudffudduke egfeelgeeigeekjefhleevnecuffhomhgrihhnpehkvghrnhgvlhdrohhrghenucevlhhu shhtvghrufhiiigvpedunecurfgrrhgrmhepmhgrihhlfhhrohhmpehgrhgvgheskhhroh grhhdrtghomh X-ME-Proxy: Received: by mail.messagingengine.com (Postfix) with ESMTPA; Sun, 27 Jun 2021 10:24:05 -0400 (EDT) Subject: FAILED: patch "[PATCH] kthread_worker: split code for canceling the delayed work" failed to apply to 4.19-stable tree To: pmladek@suse.com, akpm@linux-foundation.org, jenhaochen@google.com, liumartin@google.com, minchan@google.com, nathan@kernel.org, ndesaulniers@google.com, oleg@redhat.com, stable@vger.kernel.org, tj@kernel.org, torvalds@linux-foundation.org Cc: From: Date: Sun, 27 Jun 2021 16:23:55 +0200 Message-ID: <162480383515619@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 4.19-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 34b3d5344719d14fd2185b2d9459b3abcb8cf9d8 Mon Sep 17 00:00:00 2001 From: Petr Mladek Date: Thu, 24 Jun 2021 18:39:45 -0700 Subject: [PATCH] kthread_worker: split code for canceling the delayed work timer Patch series "kthread_worker: Fix race between kthread_mod_delayed_work() and kthread_cancel_delayed_work_sync()". This patchset fixes the race between kthread_mod_delayed_work() and kthread_cancel_delayed_work_sync() including proper return value handling. This patch (of 2): Simple code refactoring as a preparation step for fixing a race between kthread_mod_delayed_work() and kthread_cancel_delayed_work_sync(). It does not modify the existing behavior. Link: https://lkml.kernel.org/r/20210610133051.15337-2-pmladek@suse.com Signed-off-by: Petr Mladek Cc: Cc: Martin Liu Cc: Minchan Kim Cc: Nathan Chancellor Cc: Nick Desaulniers Cc: Oleg Nesterov Cc: Tejun Heo Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds diff --git a/kernel/kthread.c b/kernel/kthread.c index fe3f2a40d61e..121a0e1fc659 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -1092,6 +1092,33 @@ void kthread_flush_work(struct kthread_work *work) } EXPORT_SYMBOL_GPL(kthread_flush_work); +/* + * Make sure that the timer is neither set nor running and could + * not manipulate the work list_head any longer. + * + * The function is called under worker->lock. The lock is temporary + * released but the timer can't be set again in the meantime. + */ +static void kthread_cancel_delayed_work_timer(struct kthread_work *work, + unsigned long *flags) +{ + struct kthread_delayed_work *dwork = + container_of(work, struct kthread_delayed_work, work); + struct kthread_worker *worker = work->worker; + + /* + * del_timer_sync() must be called to make sure that the timer + * callback is not running. The lock must be temporary released + * to avoid a deadlock with the callback. In the meantime, + * any queuing is blocked by setting the canceling counter. + */ + work->canceling++; + raw_spin_unlock_irqrestore(&worker->lock, *flags); + del_timer_sync(&dwork->timer); + raw_spin_lock_irqsave(&worker->lock, *flags); + work->canceling--; +} + /* * This function removes the work from the worker queue. Also it makes sure * that it won't get queued later via the delayed work's timer. @@ -1106,23 +1133,8 @@ static bool __kthread_cancel_work(struct kthread_work *work, bool is_dwork, unsigned long *flags) { /* Try to cancel the timer if exists. */ - if (is_dwork) { - struct kthread_delayed_work *dwork = - container_of(work, struct kthread_delayed_work, work); - struct kthread_worker *worker = work->worker; - - /* - * del_timer_sync() must be called to make sure that the timer - * callback is not running. The lock must be temporary released - * to avoid a deadlock with the callback. In the meantime, - * any queuing is blocked by setting the canceling counter. - */ - work->canceling++; - raw_spin_unlock_irqrestore(&worker->lock, *flags); - del_timer_sync(&dwork->timer); - raw_spin_lock_irqsave(&worker->lock, *flags); - work->canceling--; - } + if (is_dwork) + kthread_cancel_delayed_work_timer(work, flags); /* * Try to remove the work from a worker list. It might either