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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 3ADD1C76188 for ; Tue, 16 Jul 2019 10:47:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 11D4E21721 for ; Tue, 16 Jul 2019 10:47:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733305AbfGPKrj (ORCPT ); Tue, 16 Jul 2019 06:47:39 -0400 Received: from mx2.suse.de ([195.135.220.15]:34018 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728235AbfGPKrj (ORCPT ); Tue, 16 Jul 2019 06:47:39 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 01CF9B129; Tue, 16 Jul 2019 10:47:38 +0000 (UTC) Subject: Re: [PATCH 12/12] closures: fix a race on wakeup from closure_sync To: Kent Overstreet References: <20190610191420.27007-1-kent.overstreet@gmail.com> <20190610191420.27007-13-kent.overstreet@gmail.com> Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-bcache@vger.kernel.org From: Coly Li Openpgp: preference=signencrypt Organization: SUSE Labs Message-ID: <8381178e-4c1e-e0fe-430b-a459be1a9389@suse.de> Date: Tue, 16 Jul 2019 18:47:27 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20190610191420.27007-13-kent.overstreet@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Kent, On 2019/6/11 3:14 上午, Kent Overstreet wrote: > Signed-off-by: Kent Overstreet Acked-by: Coly Li And also I receive report for suspicious closure race condition in bcache, and people ask for having this patch into Linux v5.3. So before this patch gets merged into upstream, I plan to rebase it to drivers/md/bcache/closure.c at this moment. Of cause the author is you. When lib/closure.c merged into upstream, I will rebase all closure usage from bcache to use lib/closure.{c,h}. Thanks in advance. Coly Li > --- > lib/closure.c | 10 ++++++++-- > 1 file changed, 8 insertions(+), 2 deletions(-) > > diff --git a/lib/closure.c b/lib/closure.c > index 46cfe4c382..3e6366c262 100644 > --- a/lib/closure.c > +++ b/lib/closure.c > @@ -104,8 +104,14 @@ struct closure_syncer { > > static void closure_sync_fn(struct closure *cl) > { > - cl->s->done = 1; > - wake_up_process(cl->s->task); > + struct closure_syncer *s = cl->s; > + struct task_struct *p; > + > + rcu_read_lock(); > + p = READ_ONCE(s->task); > + s->done = 1; > + wake_up_process(p); > + rcu_read_unlock(); > } > > void __sched __closure_sync(struct closure *cl) > -- Coly Li