From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-3709765-1519676187-2-13971071792734083741 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.001, ME_NOAUTH 0.01, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='CN', FromHeader='org', MailFrom='org' X-Spam-charsets: plain='UTF-8' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=arctest; t=1519676186; b=GfFePmkR2ukoC7xrlSEJsjseP3ynIJBuSUHyzk9iT6/UhG+ JtmfHH82v8OzxgucMk0oRx3yL4MtAKRwnxWTyCH20RK/XHk2QouDI5CTKEX+fTuN i9bxB57DqJqmTfAceShUZVOOcRBNj3YmQWqmXt4lEYToKGcZ00/SeEsFEVyg7vMt AaXHKBPE9ci7UwZumVRy1U4/omxWzGjyJIW1ktY9XTUZCmGPkwk/O9VJqibqbOWb SHCxPKX55Kf9z1IB7WkvN7nEDllEu5ZWPxiw1C7T92GV3i3wdYASA3s8lhSTCkKc JD/Yqn3O5+MAoUbYNLK6ruEPd6HombFs/TQOKPA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=from:to:cc:subject:date:message-id :in-reply-to:references:mime-version:content-type:sender :list-id; s=arctest; t=1519676186; bh=95LNyPy5f+BDlNmlrzTAvKpGWR 1ACRR8lOF2G9amM1k=; b=hndu9HB9+/+Aarp45IHGeMny3MhFMJIlFwJiiarD0D wHkpUoXe5t5IeClaQswUQqFKupr9PjjcjEPJ61mb/v886VH6ODkoqvxp+DygGUxx LMdR9swLz6WGT+bUIS58d7U80R2PwL0rwKWooQpTsFlXU+mUx6awVjCqVBtMIiAa GEBZKsxmIBkpQh/EUYoFe7JJZwPz+AHamY5GAdL24NJ99M5FAJY/vXkhjL4pbHr0 S1iX4QpOlpMrbIAPlln1J9glxmxsh0iCefoBEhUJnN+jxPQPGs/BwpYo4YyWQ6I/ jvavyvp90yczHGWyJ5DhQ/2dw5wuNNcjq1h7nQ8CQm/A== ARC-Authentication-Results: i=1; mx5.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=linuxfoundation.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=linuxfoundation.org header.result=pass header_is_org_domain=yes Authentication-Results: mx5.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=linuxfoundation.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=linuxfoundation.org header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751835AbeBZUQX (ORCPT ); Mon, 26 Feb 2018 15:16:23 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:59000 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751734AbeBZUQW (ORCPT ); Mon, 26 Feb 2018 15:16:22 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Arnd Bergmann , Jessica Yu , Kees Cook , Linus Torvalds , Martin Sebor , Peter Zijlstra , Robert Richter , Thomas Gleixner , oprofile-list@lists.sf.net, Ingo Molnar Subject: [PATCH 3.18 08/13] x86/oprofile: Fix bogus GCC-8 warning in nmi_setup() Date: Mon, 26 Feb 2018 21:15:36 +0100 Message-Id: <20180226201527.599704954@linuxfoundation.org> X-Mailer: git-send-email 2.16.2 In-Reply-To: <20180226201527.242286068@linuxfoundation.org> References: <20180226201527.242286068@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Arnd Bergmann commit 85c615eb52222bc5fab6c7190d146bc59fac289e upstream. GCC-8 shows a warning for the x86 oprofile code that copies per-CPU data from CPU 0 to all other CPUs, which when building a non-SMP kernel turns into a memcpy() with identical source and destination pointers: arch/x86/oprofile/nmi_int.c: In function 'mux_clone': arch/x86/oprofile/nmi_int.c:285:2: error: 'memcpy' source argument is the same as destination [-Werror=restrict] memcpy(per_cpu(cpu_msrs, cpu).multiplex, ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ per_cpu(cpu_msrs, 0).multiplex, ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ sizeof(struct op_msr) * model->num_virt_counters); ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ arch/x86/oprofile/nmi_int.c: In function 'nmi_setup': arch/x86/oprofile/nmi_int.c:466:3: error: 'memcpy' source argument is the same as destination [-Werror=restrict] arch/x86/oprofile/nmi_int.c:470:3: error: 'memcpy' source argument is the same as destination [-Werror=restrict] I have analyzed a number of such warnings now: some are valid and the GCC warning is welcome. Others turned out to be false-positives, and GCC was changed to not warn about those any more. This is a corner case that is a false-positive but the GCC developers feel it's better to keep warning about it. In this case, it seems best to work around it by telling GCC a little more clearly that this code path is never hit with an IS_ENABLED() configuration check. Cc:stable as we also want old kernels to build cleanly with GCC-8. Signed-off-by: Arnd Bergmann Cc: Jessica Yu Cc: Kees Cook Cc: Linus Torvalds Cc: Martin Sebor Cc: Peter Zijlstra Cc: Robert Richter Cc: Thomas Gleixner Cc: oprofile-list@lists.sf.net Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/20180220205826.2008875-1-arnd@arndb.de Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84095 Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- arch/x86/oprofile/nmi_int.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/x86/oprofile/nmi_int.c +++ b/arch/x86/oprofile/nmi_int.c @@ -471,7 +471,7 @@ static int nmi_setup(void) goto fail; for_each_possible_cpu(cpu) { - if (!cpu) + if (!IS_ENABLED(CONFIG_SMP) || !cpu) continue; memcpy(per_cpu(cpu_msrs, cpu).counters,