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 297F3C433EF for ; Thu, 19 May 2022 15:03:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240451AbiESPDK (ORCPT ); Thu, 19 May 2022 11:03:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42294 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240369AbiESPCw (ORCPT ); Thu, 19 May 2022 11:02:52 -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 D700BEBE8D for ; Thu, 19 May 2022 08:01:40 -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 6419CB82564 for ; Thu, 19 May 2022 15:01:39 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9FB92C34100; Thu, 19 May 2022 15:01:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1652972498; bh=vxzuV8FswPsZxFpufH17N2JgSjIsyRUE1PuUjqu6Z88=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=P6ussOQcoUaP7lZdXMnd6cuA4Ft9G2P0zq+bTtA2hkgqk5au67LheGZznguQyEhXf J1fILX4hM/myjH37Iu+zLroNcvf9FnTJ6dXYGgHoe2RF6lBnZz3xJG/OoidgaJn6Uv nk/Py3GK9MPJMpCAqggrydTCj2CcsPuOSCPWbvPQF6hiNQJF8ADefCDLIT9fOrnHqZ y8mKYYC2nkVE7W/MIUp/4KQySfDPnbk1/t3Oh2x8WC21ByKxLNd1TaZdMAK17HGdOn SfJx5OA9jzrUwVVS9rrSrCvySX480G4xmpGdbCTRU6P5ILfoXm6HltyF3N/WwdmBZI uAr9foz9tx/Ow== Date: Thu, 19 May 2022 17:01:35 +0200 From: Frederic Weisbecker To: Peter Zijlstra Cc: LKML , Phil Auld , Alex Belits , Nicolas Saenz Julienne , Xiongfeng Wang , Neeraj Upadhyay , Thomas Gleixner , Yu Liao , Boqun Feng , "Paul E . McKenney" , Marcelo Tosatti , Paul Gortmaker , Uladzislau Rezki , Joel Fernandes Subject: Re: [PATCH 03/21] rcu: Add a note about noinstr VS unsafe eqs functions Message-ID: <20220519150135.GA618878@lothringen> References: <20220503100051.2799723-1-frederic@kernel.org> <20220503100051.2799723-4-frederic@kernel.org> <20220519144821.GI2578@worktop.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220519144821.GI2578@worktop.programming.kicks-ass.net> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, May 19, 2022 at 04:48:21PM +0200, Peter Zijlstra wrote: > On Tue, May 03, 2022 at 12:00:33PM +0200, Frederic Weisbecker wrote: > > Some RCU functions enter or exit into/from RCU idle mode while using > > trace-able and lockdep-aware IRQs (un-)masking. This could be easily > > solved with using raw versions of local_irq_*() but we would then > > lose some precious debugging informations. > > > > Another possible way to solve this may consist in using rude RCU-tasks > > in lockdep and irqsoff tracing. > > > > In any case and until this get solved, those RCU functions can't get > > tagged as noinstr even though they should. > > No need to speculate on how to solve it; the generic entry code has > alternatives that are good. It's just that reworking your architecture > isn't trivial. Speaking of, please have a look at this: https://lore.kernel.org/all/20220518162118.GA2661055@paulmck-ThinkPad-P17-Gen-1/