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=-13.8 required=3.0 tests=BAYES_00, 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 117C1C47082 for ; Thu, 3 Jun 2021 06:33:27 +0000 (UTC) Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [216.205.24.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 9A285613D8 for ; Thu, 3 Jun 2021 06:33:25 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9A285613D8 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=tempfail smtp.mailfrom=dm-devel-bounces@redhat.com Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-253-UX5q7CBZMnec4OujPA2lAg-1; Thu, 03 Jun 2021 02:33:21 -0400 X-MC-Unique: UX5q7CBZMnec4OujPA2lAg-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 6F34E801817; Thu, 3 Jun 2021 06:33:12 +0000 (UTC) Received: from colo-mx.corp.redhat.com (colo-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.20]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 492B010013D7; Thu, 3 Jun 2021 06:33:12 +0000 (UTC) Received: from lists01.pubmisc.prod.ext.phx2.redhat.com (lists01.pubmisc.prod.ext.phx2.redhat.com [10.5.19.33]) by colo-mx.corp.redhat.com (Postfix) with ESMTP id 13BB51801268; Thu, 3 Jun 2021 06:33:12 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) by lists01.pubmisc.prod.ext.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id 152E6faT031417 for ; Wed, 2 Jun 2021 10:06:41 -0400 Received: by smtp.corp.redhat.com (Postfix) id 627C821D4F2A; Wed, 2 Jun 2021 14:06:41 +0000 (UTC) Received: from mimecast-mx02.redhat.com (mimecast06.extmail.prod.ext.rdu2.redhat.com [10.11.55.22]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 5E33B21D4F35 for ; Wed, 2 Jun 2021 14:06:37 +0000 (UTC) Received: from us-smtp-1.mimecast.com (us-smtp-delivery-1.mimecast.com [205.139.110.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 2D8D01825064 for ; Wed, 2 Jun 2021 14:06:37 +0000 (UTC) Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-334-UnYxdOsTMzu-vRHeTa9yxA-1; Wed, 02 Jun 2021 10:06:34 -0400 X-MC-Unique: UnYxdOsTMzu-vRHeTa9yxA-1 Received: by mail.kernel.org (Postfix) with ESMTPSA id 09B1D60FE3; Wed, 2 Jun 2021 13:58:06 +0000 (UTC) Date: Wed, 2 Jun 2021 15:58:04 +0200 From: Greg Kroah-Hartman To: Peter Zijlstra Message-ID: References: <20210602131225.336600299@infradead.org> <20210602133040.271625424@infradead.org> MIME-Version: 1.0 In-Reply-To: <20210602133040.271625424@infradead.org> X-Mimecast-Impersonation-Protect: Policy=CLT - Impersonation Protection Definition; Similar Internal Domain=false; Similar Monitored External Domain=false; Custom External Domain=false; Mimecast External Domain=false; Newly Observed Domain=false; Internal User Name=false; Custom Display Name List=false; Reply-to Address Mismatch=false; Targeted Threat Dictionary=false; Mimecast Threat Dictionary=false; Custom Threat Dictionary=false X-Scanned-By: MIMEDefang 2.78 on 10.11.54.6 X-loop: dm-devel@redhat.com X-Mailman-Approved-At: Thu, 03 Jun 2021 02:32:49 -0400 Cc: Juri Lelli , Mark Rutland , Pavel Machek , Mike Snitzer , Alexander Shishkin , kgdb-bugreport@lists.sourceforge.net, Lai Jiangshan , Oleg Nesterov , Ben Segall , linux-mm@kvack.org, dm-devel@redhat.com, Paolo Bonzini , Zefan Li , "H. Peter Anvin" , Joel Fernandes , Jiri Olsa , Alasdair Kergon , Daniel Thompson , Davidlohr Bueso , Vincent Guittot , kvm@vger.kernel.org, Will Deacon , cgroups@vger.kernel.org, x86@kernel.org, Ingo Molnar , Mel Gorman , Jakub Kicinski , John Stultz , "Paul E. McKenney" , linux-pm@vger.kernel.org, Boqun Feng , Jason Wessel , Josh Triplett , Steven Rostedt , linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, Borislav Petkov , Alexander Viro , Waiman Long , Namhyung Kim , Thomas Gleixner , Arnaldo Carvalho de Melo , Dietmar Eggemann , Jens Axboe , Felipe Balbi , Stephen Boyd , netdev@vger.kernel.org, linux-usb@vger.kernel.org, "Rafael J. Wysocki" , Douglas Anderson , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, Johannes Weiner , Tejun Heo , Mathieu Desnoyers , Andrew Morton , rcu@vger.kernel.org, Daniel Bristot de Oliveira , "David S. Miller" Subject: Re: [dm-devel] [PATCH 1/6] sched: Unbreak wakeups X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dm-devel-bounces@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Disposition: inline Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit On Wed, Jun 02, 2021 at 03:12:26PM +0200, Peter Zijlstra wrote: > Remove broken task->state references and let wake_up_process() DTRT. > > The anti-pattern in these patches breaks the ordering of ->state vs > COND as described in the comment near set_current_state() and can lead > to missed wakeups: > > (OoO load, observes RUNNING)<-. > for (;;) { | > t->state = UNINTERRUPTIBLE; | > smp_mb(); ,-----> ,' (OoO load, observed !COND) > | | > | | COND = 1; > | `- if (t->state != RUNNING) > | wake_up_process(t); // not done > if (COND) ---------' > break; > schedule(); // forever waiting > } > t->state = TASK_RUNNING; > > Signed-off-by: Peter Zijlstra (Intel) > --- > drivers/net/ethernet/qualcomm/qca_spi.c | 6 ++---- > drivers/usb/gadget/udc/max3420_udc.c | 15 +++++---------- > drivers/usb/host/max3421-hcd.c | 3 +-- > kernel/softirq.c | 2 +- > 4 files changed, 9 insertions(+), 17 deletions(-) For USB stuff: Acked-by: Greg Kroah-Hartman -- dm-devel mailing list dm-devel@redhat.com https://listman.redhat.com/mailman/listinfo/dm-devel