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=-14.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 3AA85C41604 for ; Wed, 7 Oct 2020 21:05:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DAAC320872 for ; Wed, 7 Oct 2020 21:05:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602104705; bh=XuzH5blWHlB+mMmnzqx+vTR+L4nIxHQHXzopJDP9T6c=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:List-ID: From; b=C4EcapoTOZ47hfprGcC3yWFpeTln0jgbgadKYEduy7uEs/i6mv76M5+hzKlTscfSA m6QEUWy/2aGBMNYgPakEl85YRpxXeD+st0Kgcm9jPvK5SJsxP1Xv5C8KSz8hnZ3sXB 53VDgZatzDcW+hUTTRnGBJToLMYzIPxqQlWobqNQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728345AbgJGVFF (ORCPT ); Wed, 7 Oct 2020 17:05:05 -0400 Received: from mail.kernel.org ([198.145.29.99]:37990 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726013AbgJGVFE (ORCPT ); Wed, 7 Oct 2020 17:05:04 -0400 Received: from paulmck-ThinkPad-P72.home (50-39-104-11.bvtn.or.frontiernet.net [50.39.104.11]) (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 9D40A2083B; Wed, 7 Oct 2020 21:05:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602104703; bh=XuzH5blWHlB+mMmnzqx+vTR+L4nIxHQHXzopJDP9T6c=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:From; b=VhX4nlu/c0Wk6+Td2+6byKSsBxCZ8w0R96WYH70E77KiYjTgpMHgJQHU067CJp9o3 aaGbtFNqeXLmxazip/eD005dAwErHTM10n11kNTT+PB98OC/iNJ5AyNUx+yzPc0uEZ zDJvadSUUqyVrYb9W/aLWDOMz7irNz0PSQLg8V/o= Received: by paulmck-ThinkPad-P72.home (Postfix, from userid 1000) id 4F0763522FA4; Wed, 7 Oct 2020 14:05:03 -0700 (PDT) Date: Wed, 7 Oct 2020 14:05:03 -0700 From: "Paul E. McKenney" To: Nathan Chancellor Cc: Sedat Dilek , Nick Desaulniers , Steven Rostedt , Mathieu Desnoyers , Lai Jiangshan , Josh Triplett , Kees Cook , LKML , rcu@vger.kernel.org, clang-built-linux Subject: Re: [PATCH v2] srcu: avoid escaped section names Message-ID: <20201007210503.GR29330@paulmck-ThinkPad-P72> Reply-To: paulmck@kernel.org References: <20200929192549.501516-1-ndesaulniers@google.com> <20200930204044.GZ29330@paulmck-ThinkPad-P72> <20201002205130.GK29330@paulmck-ThinkPad-P72> <20201005184910.GC29330@paulmck-ThinkPad-P72> <20201006065623.GA2418984@ubuntu-m3-large-x86> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201006065623.GA2418984@ubuntu-m3-large-x86> User-Agent: Mutt/1.9.4 (2018-02-28) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Oct 05, 2020 at 11:56:23PM -0700, Nathan Chancellor wrote: > On Mon, Oct 05, 2020 at 11:49:10AM -0700, Paul E. McKenney wrote: > > On Mon, Oct 05, 2020 at 08:38:42PM +0200, Sedat Dilek wrote: > > > On Mon, Oct 5, 2020 at 8:29 PM 'Nick Desaulniers' via Clang Built > > > Linux wrote: > > > > > > > > On Fri, Oct 2, 2020 at 1:51 PM Paul E. McKenney wrote: > > > > > > > > > > On Wed, Sep 30, 2020 at 01:55:48PM -0700, Nick Desaulniers wrote: > > > > > > On Wed, Sep 30, 2020 at 1:40 PM Paul E. McKenney wrote: > > > > > > > > > > > > > > On Tue, Sep 29, 2020 at 12:25:49PM -0700, Nick Desaulniers wrote: > > > > > > > > The stringification operator, `#`, in the preprocessor escapes strings. > > > > > > > > For example, `# "foo"` becomes `"\"foo\""`. GCC and Clang differ in how > > > > > > > > they treat section names that contain \". > > > > > > > > > > > > > > > > The portable solution is to not use a string literal with the > > > > > > > > preprocessor stringification operator. > > > > > > > > > > > > > > > > Link: https://bugs.llvm.org/show_bug.cgi?id=42950 > > > > > > > > Fixes: commit fe15b50cdeee ("srcu: Allocate per-CPU data for DEFINE_SRCU() in modules") > > > > > > > > Signed-off-by: Nick Desaulniers > > > > > > > > > > > > > > I am guessing that this needs to go up with other patches. If so: > > > > > > > > > > > > > > Acked-by: Paul E. McKenney > > > > > > > > > > > > > > If not, let me know and I will queue it. > > > > > > > > > > > > I could have bundled them up as a series. I think you can pick it up, > > > > > > and I'll owe you a beer? > > > > > > > > > > It is queued, thank you! > > > > > > > > > > When does it need to hit mainline? (Your default is the v5.11 merge > > > > > window, that is, the one following the upcoming merge window.) > > > > > > > > No rush, this patch wasn't blocking any known issue, just a cleanup > > > > while I was in the neighborhood. 100 years ago, I was an Eagle scout. > > > > Pretty sure there was a motto about "leaving things better than you > > > > found them." Thanks for help resolving the merge conflict reported in > > > > -next related to it. > > > > > > Wasn't there a problem with your "Fixes:" tag (Fixes: *drop word > > > "commit"* commit_hashid ("...")? > > > > Indeed there was, and I have it noted to be fixed on my next rebase. > > > > Perhaps another reason not to rush to mainline though. ;-) > > > > Thanx, Paul > > I am replying here as well so that the relevant parties are in the know > but I believe this patch should be fast tracked with a cc stable tag as > this appears to be the root cause of the issue that Nick reported a few > weeks ago: > > https://lore.kernel.org/rcu/CAKwvOdm4AQhobdkKT08bjPGb15N58QN79XWxEaQt-P5Dk4+avQ@mail.gmail.com/ > https://github.com/ClangBuiltLinux/linux/issues/1081 > > I can reproduce the issue on next-20201002 on my Raspberry Pi 4 just by > booting it up. As soon as I apply this patch, all warnings disappear. I > asked the original reporters to test if the patch resolves the issue for > them but I figured more visibility on this, the sooner. The commit > message might need to be revised if this turns out to be the case to > make it more apparent that it has a user visible issue, rather than just > a QoL fix. > > Additionally, it seems like the patch is missing some reviewed by tags > from Kees, Sedat, and myself. Feel free to add a > > Tested-by: Nathan Chancellor > > as well. Good catch, and apologies to all concerned! I have removed the stray "commit" and, based posts earlier in this thread, I have also added: Reviewed-by: Kees Cook Reviewed-by: Nathan Chancellor Tested-by: Nathan Chancellor Reviewed-by: Sedat Dilek Thank you all! Thanx, Paul