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=-7.1 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 53CD8C4727E for ; Wed, 30 Sep 2020 15:56:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 01FC320759 for ; Wed, 30 Sep 2020 15:56:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601481403; bh=2ka6fzAEuxPuQ4TR1P9mDcvXBeBVOUozqRglKos8gkA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=j6mdbzIfW+q+AcZC6a3f+0WDU5y726AJKxrg2wVbSLKJHF+pY8xynK4R91m8sMCR1 kXK4YM/Lmd+rBCf8V1IY+0c7nWkHzVKi8uyDm9BfCQgdZb7z8v1BwvkwyLVR9bWQFH 7xp9IXWoYjgQNRzUXzYC7Pgdd+5tBBCopaGaM06E= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730804AbgI3P4l (ORCPT ); Wed, 30 Sep 2020 11:56:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46564 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725872AbgI3P4l (ORCPT ); Wed, 30 Sep 2020 11:56:41 -0400 Received: from mail-qv1-xf41.google.com (mail-qv1-xf41.google.com [IPv6:2607:f8b0:4864:20::f41]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 79993C061755 for ; Wed, 30 Sep 2020 08:56:41 -0700 (PDT) Received: by mail-qv1-xf41.google.com with SMTP id cr8so1131763qvb.10 for ; Wed, 30 Sep 2020 08:56:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=JiVCTNkd5z0wAMKWbNh0KXmrcEj0udA/gKZKa+V4uPI=; b=BcM3XgWxfWsGNSnSn58+s3PRrQp4hZLVuCRH8bzL/XPbdPW4+kGhb1jm4Twkwaj3oq 16cABXPrl+QfaT5hs7ZqTGNa85gJs3lN56Az0C3/1IX76CKD8D6y2tYL4DxycZUdPX8M RT9AF5Xnix9k6KXOOUF6qPMxOfZqNUDbI+mfrzqqYGklmjFNT3BkAcGVjxIKHgf3qNEU yMUwRqzV5SwitjPL20t16Z07KgqY4z6QYHKxJavp0O23owHzRRJKN/EFnAM+LL0d1XNP +mdu+FRXRvFYJeHWVPNIIFA8O0LA/ucjQnyI05ycZFTHdARLoh6S+ecI0Yh1w4obyO52 2jVQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to; bh=JiVCTNkd5z0wAMKWbNh0KXmrcEj0udA/gKZKa+V4uPI=; b=ZxjYIYi+eui8Jor50q1NpeQ/VkkfqbV1SYGK4sKQob/fpTRB7ifhz8qjX9+YJGlYT9 gWVsuaLlrXyJunIoc0qJAxfe5HwUMRDddWMOht66/826MV/JEbYTGIu1RRV46T7qVk3l y9cdinJmmR+KJxi1ffzJOHSzHqPmeCJwRJrO60Pk3ItXNCETxQgoTD8UD7/NyVB2gufx 3trwvfDVHHkEjtSiT/xq6H0DZP1sGeFKrKEFbZsgzrLezKWHtmxir0kfRMcNxRbucblj oHtsmuc2bV7wPz3UVr/mt5N3Kz/7s4buRCCiVJCWbOnTYw26IR+5SD+4FxlCmuCQK00r bIaQ== X-Gm-Message-State: AOAM530PVLpFw4/k899hUkg4CJhpU4vnOM5qAeBakjBliqRNyhC9Uamk f6gZnrIg+it0CXFiGgUAPbU= X-Google-Smtp-Source: ABdhPJw4ANufMovxtypxexuQ0beQ6BoTgM9M7QbgjuPIoGuzLV77CDCUHKpow9riDtRKm867jq0eNQ== X-Received: by 2002:a0c:e152:: with SMTP id c18mr2982345qvl.41.1601481400327; Wed, 30 Sep 2020 08:56:40 -0700 (PDT) Received: from localhost ([2620:10d:c091:480::1:e9fa]) by smtp.gmail.com with ESMTPSA id i62sm2618113qkf.36.2020.09.30.08.56.39 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 30 Sep 2020 08:56:39 -0700 (PDT) Sender: Tejun Heo Date: Wed, 30 Sep 2020 11:56:38 -0400 From: Tejun Heo To: qiang.zhang@windriver.com Cc: pmladek@suse.com, hdanton@sina.com, akpm@linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3] kthread_worker: Prevent queuing delayed work from timer_fn when it is being canceled Message-ID: <20200930155638.GA4441@mtj.duckdns.org> References: <20200927055449.21389-1-qiang.zhang@windriver.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200927055449.21389-1-qiang.zhang@windriver.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Sep 27, 2020 at 01:54:49PM +0800, qiang.zhang@windriver.com wrote: > From: Zqiang > > 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. > > Reviewed-by: Petr Mladek > Signed-off-by: Zqiang Acked-by: Tejun Heo This prolly should go throgh -mm. Can you please also add a stable: tag? Thanks. -- tejun