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,HEADER_FROM_DIFFERENT_DOMAINS,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 993D5C433DF for ; Mon, 10 Aug 2020 10:35:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 75B7A2070B for ; Mon, 10 Aug 2020 10:35:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="OZO9eCCz"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="PPxvtWc+" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726453AbgHJKfJ (ORCPT ); Mon, 10 Aug 2020 06:35:09 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:50350 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726304AbgHJKfI (ORCPT ); Mon, 10 Aug 2020 06:35:08 -0400 Date: Mon, 10 Aug 2020 12:35:08 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1597055706; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=OjjK56vi+OiP5R8kvP7R0V1sr3ZxerDdKSGBt8tWSbQ=; b=OZO9eCCzf/3FQy2RL+5yiI9OGswKwcIhDTU8S2Ozq/N2JddZQYpKPBJk9frCsslIWY9a3x RQd5Nsobt+Wi8DuFCgXteXUBNX5EwquY9WL1eyHEmhTWxI8ByIxt/hGVNH8nh4l8c2mGVv XU8bcwZDUd7crDKUFtUnE8cExP08f50PVKWu5SHSpcuUS8SZJKCBE2FrZ9noktnTvrc4zp S8yF10T4rwXnJFEd8ahpRAFuKGylLNlm/MkhxSfmGUl4i2xKz0KTASQCvFxB/1p4+aNE58 4u7HCWu7tJjfXzJ5eueKNxyYG/sxsWJVMaB2XdS9Ve9Q3rV+hOsEJsQZ/XU0EA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1597055706; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=OjjK56vi+OiP5R8kvP7R0V1sr3ZxerDdKSGBt8tWSbQ=; b=PPxvtWc+bZcQfLzOZptxtrftfrk8+YBuhoUU0Wte37IcC0x5NTrK40eW/1Pjn4+ftQYMo3 1lss+rc6rVql0ABg== From: "Ahmed S. Darwish" To: Greg KH Cc: bigeasy@linutronix.de, linux-kernel@vger.kernel.org, linux@roeck-us.net, mingo@redhat.com, paulmck@kernel.org, peterz@infradead.org, rostedt@goodmis.org, tglx@linutronix.de, will@kernel.org Subject: Re: [PATCH] Revert "seqlock: lockdep assert non-preemptibility on seqcount_t write" Message-ID: <20200810103508.GA142779@lx-t490> References: <20200810085954.GA1591892@kroah.com> <20200810095428.2602276-1-a.darwish@linutronix.de> <20200810100502.GA2406768@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200810100502.GA2406768@kroah.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 10, 2020 at 12:05:02PM +0200, Greg KH wrote: > On Mon, Aug 10, 2020 at 11:54:28AM +0200, Ahmed S. Darwish wrote: > > This reverts commit 859247d39fb008ea812e8f0c398a58a20c12899e. > > > > Current implementation of lockdep_assert_preemption_disabled() uses > > per-CPU variables, which was done to untangle the existing > > seqlock.h<=>sched.h 'current->' task_struct circular dependency. > > > > Using per-CPU variables did not fully untangle the dependency for > > various non-x86 architectures though, resulting in multiple broken > > builds. For the affected architectures, raw_smp_processor_id() led > > back to 'current->', thus having the original seqlock.h<=>sched.h > > dependency in full-effect. > > > > For now, revert adding lockdep_assert_preemption_disabled() to > > seqlock.h. > > > > Reported-by: Guenter Roeck > > Link: https://lkml.kernel.org/r/20200808232122.GA176509@roeck-us.net > > Link: https://lkml.kernel.org/r/20200810085954.GA1591892@kroah.com > > References: Commit a21ee6055c30 ("lockdep: Change hardirq{s_enabled,_context} to per-cpu variables") > > Signed-off-by: Ahmed S. Darwish > > Reviewed-by: Greg Kroah-Hartman > > Even after this, there are still some build errors on arm32, but I don't > think they are due to this change: > > ERROR: modpost: "__aeabi_uldivmod" [drivers/net/ethernet/sfc/sfc.ko] undefined! > ERROR: modpost: "__bad_udelay" [drivers/net/ethernet/aquantia/atlantic/atlantic.ko] undefined! > Yes, they are unrelated to the seqlock.h changes. (I've locally reverted the whole series just to be sure, and the same linking errors as above were still there for an ARM allyesconfig.) Thanks, -- Ahmed S. Darwish Linutronix GmbH