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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5FFB4C433F5 for ; Tue, 5 Oct 2021 14:37:31 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id D8EF061381 for ; Tue, 5 Oct 2021 14:37:30 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org D8EF061381 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id 722FA6B0071; Tue, 5 Oct 2021 10:37:30 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 6A98C900003; Tue, 5 Oct 2021 10:37:30 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 54A63900002; Tue, 5 Oct 2021 10:37:30 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0086.hostedemail.com [216.40.44.86]) by kanga.kvack.org (Postfix) with ESMTP id 44F266B0071 for ; Tue, 5 Oct 2021 10:37:30 -0400 (EDT) Received: from smtpin29.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 0A4D882499A8 for ; Tue, 5 Oct 2021 14:37:30 +0000 (UTC) X-FDA: 78662637060.29.4B6435A Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) by imf28.hostedemail.com (Postfix) with ESMTP id 5668A9001357 for ; Tue, 5 Oct 2021 14:37:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=NXVT547q11vxBmN0JnCHuyJ+/+kUBjr0nC1nL/Y5gs8=; b=mP1JnpeUdMoGUG0of2rU8oOvaR n7csvi9rY8/SEFwTuD6fzd+RSWW8AjhudXBQEJl2V5sOSMGFsjQbWG/AH5UhHDHKEuXfglXOGm25M JgVLJRTXxeg/i3Gq7waOsj2cBgOS3kPVMTolADirJaGu8H0NCsnkgZtZ7+Mf5WKWa/8kRTyIUFUBI q8PL3uMiyVJJmGBXP7KUAhgouW2MeZzn4zZny0oK8FZ18stFi47qmgU3NROIBuavFPsqzM/F+bNuZ xmAPZ5YvZqGVFtxTLfqX9PFJdQW9XVgPe1GCuqvR59RoAecUagUq6sUF1/NG3yy8HzY6st8oSDua+ Njbx8NBw==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1mXlZI-00846d-FS; Tue, 05 Oct 2021 14:37:20 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 9DD7930019C; Tue, 5 Oct 2021 16:37:19 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 7D60D2038E211; Tue, 5 Oct 2021 16:37:19 +0200 (CEST) Date: Tue, 5 Oct 2021 16:37:19 +0200 From: Peter Zijlstra To: Marco Elver Cc: "Paul E . McKenney" , Alexander Potapenko , Boqun Feng , Borislav Petkov , Dmitry Vyukov , Ingo Molnar , Josh Poimboeuf , Mark Rutland , Thomas Gleixner , Waiman Long , Will Deacon , kasan-dev@googlegroups.com, linux-arch@vger.kernel.org, linux-doc@vger.kernel.org, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org Subject: Re: [PATCH -rcu/kcsan 23/23] objtool, kcsan: Remove memory barrier instrumentation from noinstr Message-ID: References: <20211005105905.1994700-1-elver@google.com> <20211005105905.1994700-24-elver@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20211005105905.1994700-24-elver@google.com> X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 5668A9001357 X-Stat-Signature: t6dw431f8way9y435r3jb9cibb43ykz5 Authentication-Results: imf28.hostedemail.com; dkim=pass header.d=infradead.org header.s=desiato.20200630 header.b=mP1JnpeU; spf=none (imf28.hostedemail.com: domain of peterz@infradead.org has no SPF policy when checking 90.155.92.199) smtp.mailfrom=peterz@infradead.org; dmarc=none X-HE-Tag: 1633444649-223763 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Oct 05, 2021 at 12:59:05PM +0200, Marco Elver wrote: > Teach objtool to turn instrumentation required for memory barrier > modeling into nops in noinstr text. > > The __tsan_func_entry/exit calls are still emitted by compilers even > with the __no_sanitize_thread attribute. The memory barrier > instrumentation will be inserted explicitly (without compiler help), and > thus needs to also explicitly be removed. How is arm64 and others using kernel/entry + noinstr going to fix this? ISTR they fully rely on the compilers not emitting instrumentation, since they don't have objtool to fix up stray issues like this.