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=-11.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 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 37486C5519F for ; Sat, 14 Nov 2020 19:24:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E96FC22269 for ; Sat, 14 Nov 2020 19:24:19 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="Irn1YITZ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726196AbgKNTYT (ORCPT ); Sat, 14 Nov 2020 14:24:19 -0500 Received: from mail.kernel.org ([198.145.29.99]:53696 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726125AbgKNTYS (ORCPT ); Sat, 14 Nov 2020 14:24:18 -0500 Received: from tzanussi-mobl (c-73-209-127-30.hsd1.il.comcast.net [73.209.127.30]) (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 976DE22265; Sat, 14 Nov 2020 19:24:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1605381858; bh=oAUh7waXSZLaP9xaixIDertHYoeWyt+PRxnBjA/2DWU=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=Irn1YITZ6QNPml7NRgb0h06X3+Jd2sRRsCwE1XexZFjsBpYnodCUF68GEAeQ3Wdrt zuDfdEavBc1F8Ix0mREctGn/w+cz2DNRbZRPZEatF/lsrltAzW2DGFHXRRx9yFwJl0 8JKIPfSNdzKRAJfUc2JUrlDffGuQn5ibicvfQp2w= Message-ID: <0936e53c297ef3202ce3a48a135053f468c427af.camel@kernel.org> Subject: Re: [PATCH RT 1/5] net: Properly annotate the try-lock for the seqlock From: Tom Zanussi To: Mike Galbraith , Steven Rostedt , linux-kernel@vger.kernel.org, linux-rt-users Cc: Thomas Gleixner , Carsten Emde , Sebastian Andrzej Siewior , John Kacur , Daniel Wagner , "Srivatsa S. Bhat" , stable-rt@vger.kernel.org Date: Sat, 14 Nov 2020 13:24:16 -0600 In-Reply-To: <6209c8773bb1d361266046323f266526a810f850.camel@gmx.de> References: <20201110153853.463368981@goodmis.org> <20201110154024.958923729@goodmis.org> <617eb5e8478df466afa9013b02a2425f7c4c673f.camel@kernel.org> <6209c8773bb1d361266046323f266526a810f850.camel@gmx.de> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.28.5-0ubuntu0.18.04.1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 2020-11-14 at 20:00 +0100, Mike Galbraith wrote: > On Fri, 2020-11-13 at 14:14 -0600, Tom Zanussi wrote: > > > > This patch seems to fix it for me: > > If there was any discussion about this patch, I missed it. There wasn't, just this thread. > > > From 4855377d0cb34b1b67a5c6d84cc8609c9da0bc3e Mon Sep 17 00:00:00 > > 2001 > > Message-Id: < > > 4855377d0cb34b1b67a5c6d84cc8609c9da0bc3e.1605297603.git.zanussi@kernel.org > > > > > From: Tom Zanussi > > Date: Fri, 13 Nov 2020 13:04:15 -0600 > > Subject: [PATCH] net: Add missing __raw_write_seqcount_end() and > > seqcount_release() > > > > The patch ('net: Properly annotate the try-lock for the seqlock") > > adds > > __raw_write_seqcount_begin() in qdisc_run_begin() but omits the > > corresponding __raw_write_seqcount_end() and seqcount_release() in > > qdisc_run_end(). > > > > Add it unconditionally, since qdisc_run_end() is never called > > unless > > qdisc_run_begin() succeeds, and if it succeeds, > > __raw_write_seqcount_begin() seqcount_acquire() will have been > > called. > > > > Signed-off-by: Tom Zanussi > > --- > > include/net/sch_generic.h | 4 ++++ > > 1 file changed, 4 insertions(+) > > > > diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h > > index 112d2dca8b08..c5ccce4f8f62 100644 > > --- a/include/net/sch_generic.h > > +++ b/include/net/sch_generic.h > > @@ -192,7 +192,11 @@ static inline bool qdisc_run_begin(struct > > Qdisc *qdisc) > > static inline void qdisc_run_end(struct Qdisc *qdisc) > > { > > #ifdef CONFIG_PREEMPT_RT > > + seqcount_t *s = &qdisc->running.seqcount; > > + > > write_sequnlock(&qdisc->running); > > + __raw_write_seqcount_end(s); > > + seqcount_release(&s->dep_map, 1, _RET_IP_); > > #else > > write_seqcount_end(&qdisc->running); > > #endif > > __raw_write_seqcount_end() is an integral part of write_sequnlock(), > but we do seem to be missing a seqcount_release() in 5.4-rt. > Yep, you're right, it's just the missing seqcount_release() - I'll resubmit with just that. Thanks, Tom > -Mike >