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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 14459C4332F for ; Wed, 19 Oct 2022 19:14:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229753AbiJSTO3 (ORCPT ); Wed, 19 Oct 2022 15:14:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54322 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229972AbiJSTOX (ORCPT ); Wed, 19 Oct 2022 15:14:23 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 69B776304; Wed, 19 Oct 2022 12:14:21 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 1F46FB81E62; Wed, 19 Oct 2022 19:14:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C1F30C433D6; Wed, 19 Oct 2022 19:14:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1666206858; bh=ZnaNNe4+IYDPSjHEvFMiErBoP5l71S+0Eij3ayOtFl0=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:From; b=SDNsL1/j6RZ1QROiYf/v+ERgbVDQU/eheiZDuXxsJ75L9RWgZwyu8amGBysSIAj3O prvImTPP4afi7jtRxEFxTVCIM1lMNnobsgZsfB08JY+Yp2GfCwuxa9fPiWI6SQhSn+ zmNbZrshfgZKdtISBLzxApm1sJVZtM+MXe/2CllCKTpfn7xlhBf4UaQUBCP3bROFx4 5UhIfeU4S7NHiIrHbjNZHOfjFseh4VyKm7BGJtEFRIO8FjxErnmhCEeSK3alWog8/H ISf6TQqcWl5ZJ3YnGwO4O0lT6xISZkYQ4WlOkASwBIWg8G9nbXoyNQ3DjLQiimo7jc SL+TtW69P10lA== Received: by paulmck-ThinkPad-P17-Gen-1.home (Postfix, from userid 1000) id 5E90E5C06B4; Wed, 19 Oct 2022 12:14:18 -0700 (PDT) Date: Wed, 19 Oct 2022 12:14:18 -0700 From: "Paul E. McKenney" To: John Ogness Cc: rcu@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com, rostedt@goodmis.org, tglx@linutronix.de, pmladek@suse.com, Frederic Weisbecker Subject: Re: [PATCH v2 rcu 0/8] NMI-safe SRCU reader API Message-ID: <20221019191418.GF5600@paulmck-ThinkPad-P17-Gen-1> Reply-To: paulmck@kernel.org References: <20220921144620.GA1200846@paulmck-ThinkPad-P17-Gen-1> <20220929180714.GA2874192@paulmck-ThinkPad-P17-Gen-1> <87k04x4e0r.fsf@jogness.linutronix.de> <20221018152418.GR5600@paulmck-ThinkPad-P17-Gen-1> <87ilkh0y52.fsf@jogness.linutronix.de> <20221018185936.GX5600@paulmck-ThinkPad-P17-Gen-1> <20221018215721.GA1716567@paulmck-ThinkPad-P17-Gen-1> <87pmeoawwe.fsf@jogness.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87pmeoawwe.fsf@jogness.linutronix.de> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Oct 19, 2022 at 01:19:53PM +0206, John Ogness wrote: > On 2022-10-18, "Paul E. McKenney" wrote: > > And the v6.1-rc1 stack is now at srcunmisafe.2022.10.18b. > > Thanks! > > I guess the kernel test robot will catch this, but if you checkout > commit 79c95dc428ad ("arch/x86: Add ARCH_HAS_NMI_SAFE_THIS_CPU_OPS > Kconfig option") and build for x86_64, you will get: > > x86_64-linux-gnu-ld: kernel/rcu/srcutree.o: in function `srcu_gp_start_if_needed': > srcutree.c:(.text+0x133a): undefined reference to `__srcu_read_lock_nmisafe' > x86_64-linux-gnu-ld: srcutree.c:(.text+0x1490): undefined reference to `__srcu_read_unlock_nmisafe' > x86_64-linux-gnu-ld: kernel/rcu/srcutree.o: in function `srcu_barrier': > srcutree.c:(.text+0x1b03): undefined reference to `__srcu_read_lock_nmisafe' > x86_64-linux-gnu-ld: srcutree.c:(.text+0x1b38): undefined reference to `__srcu_read_unlock_nmisafe' > > Note that this error is fixed with a later commit: > > commit c2d158a284ab ("srcu: Debug NMI safety even on archs that don't > require it"). > > This does not affect what I am working on, so feel free to take care of > it whenever it fits your schedule. Good catch, thank you! It looks like the first two hunks in include/linux/srcu.h from that later commit need to be in that earlier commit. Frederic, does this make sense, or am I off in the weeds? If so, my thought is to make this change in the name of bisectability, then produce a new srcunmisafe branch. The printk() series would then need to rebase or remerge this new series. John, would that work for you? Thanx, Paul