From patchwork Tue Nov 3 18:17:12 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 317242 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=-6.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 75A98C388F7 for ; Tue, 3 Nov 2020 18:17:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2913122280 for ; Tue, 3 Nov 2020 18:17:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604427434; bh=n5wNWjXf1491Qk/AIDVyyhHom6cYu3MkQPqbgLrwhwA=; h=Date:From:To:Subject:List-ID:From; b=RlP/TQ0arxqC1qrECsyVXryxv7IsDSAf8vL9lP3QzYGTL25QP+dYLVFcXFDpf/RNP Pwcd7WW04WwtqHnRnE42QVnJlijH4dXT9PXJrii+uKiJ2JVT0BowPSUu4SmGvHYYs6 T5G89T83eAQeK+0+X4bZXpJCx44O/ApnHr37w9Ho= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729188AbgKCSRN (ORCPT ); Tue, 3 Nov 2020 13:17:13 -0500 Received: from mail.kernel.org ([198.145.29.99]:39556 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725385AbgKCSRN (ORCPT ); Tue, 3 Nov 2020 13:17:13 -0500 Received: from localhost.localdomain (c-71-198-47-131.hsd1.ca.comcast.net [71.198.47.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 826A22080D; Tue, 3 Nov 2020 18:17:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604427432; bh=n5wNWjXf1491Qk/AIDVyyhHom6cYu3MkQPqbgLrwhwA=; h=Date:From:To:Subject:From; b=ChdmoIFWZGTcsGaBA/SWvHBA/HQZd4a5Y+0+78ZPI++ODKfRBIGIO3ZdzCxYIi24J DtkDJM67+YwO4M9Hb5h83C4fcMwztNaxHsRDo0dE1UClAh6fjjVNccMovBMGT3DKhS sfX3G7cAnOnijSMP+S/LtaIOTSS5Zm/SGpwXNbYw= Date: Tue, 03 Nov 2020 10:17:12 -0800 From: akpm@linux-foundation.org To: mm-commits@vger.kernel.org, pmladek@suse.com, qiang.zhang@windriver.com, stable@vger.kernel.org, tj@kernel.org Subject: [merged] kthread_worker-prevent-queuing-delayed-work-from-timer_fn-when-it-is-being-canceled.patch removed from -mm tree Message-ID: <20201103181712.QU928QUTg%akpm@linux-foundation.org> User-Agent: s-nail v14.8.16 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch titled Subject: kthread_worker: prevent queuing delayed work from timer_fn when it is being canceled has been removed from the -mm tree. Its filename was kthread_worker-prevent-queuing-delayed-work-from-timer_fn-when-it-is-being-canceled.patch This patch was dropped because it was merged into mainline or a subsystem tree ------------------------------------------------------ From: Zqiang Subject: kthread_worker: prevent queuing delayed work from timer_fn when it is being canceled There is a small race window when a delayed work is being canceled and the work still might be queued from the timer_fn: CPU0 CPU1 kthread_cancel_delayed_work_sync() __kthread_cancel_work_sync() __kthread_cancel_work() work->canceling++; kthread_delayed_work_timer_fn() kthread_insert_work(); BUG: kthread_insert_work() should not get called when work->canceling is set. Link: https://lkml.kernel.org/r/20201014083030.16895-1-qiang.zhang@windriver.com Signed-off-by: Zqiang Reviewed-by: Petr Mladek Acked-by: Tejun Heo Cc: Signed-off-by: Andrew Morton --- kernel/kthread.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/kernel/kthread.c~kthread_worker-prevent-queuing-delayed-work-from-timer_fn-when-it-is-being-canceled +++ a/kernel/kthread.c @@ -897,7 +897,8 @@ void kthread_delayed_work_timer_fn(struc /* Move the work from worker->delayed_work_list. */ WARN_ON_ONCE(list_empty(&work->node)); list_del_init(&work->node); - kthread_insert_work(worker, work, &worker->work_list); + if (!work->canceling) + kthread_insert_work(worker, work, &worker->work_list); raw_spin_unlock_irqrestore(&worker->lock, flags); }