From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f180.google.com (mail-pf0-f180.google.com [209.85.192.180]) by kanga.kvack.org (Postfix) with ESMTP id C517F6B0256 for ; Thu, 10 Dec 2015 11:01:35 -0500 (EST) Received: by pfnn128 with SMTP id n128so50064485pfn.0 for ; Thu, 10 Dec 2015 08:01:35 -0800 (PST) Received: from mx2.parallels.com (mx2.parallels.com. [199.115.105.18]) by mx.google.com with ESMTPS id rm10si21082333pab.25.2015.12.10.08.01.34 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 10 Dec 2015 08:01:35 -0800 (PST) Subject: Re: [linux-next:master 5266/5426] arch/x86/kernel/cpu/mcheck/mce.c:884:5: warning: 'order' may be used uninitialized in this function References: <201512102333.nZemw8i3%fengguang.wu@intel.com> From: Andrey Ryabinin Message-ID: <5669A205.7080205@virtuozzo.com> Date: Thu, 10 Dec 2015 19:02:13 +0300 MIME-Version: 1.0 In-Reply-To: <201512102333.nZemw8i3%fengguang.wu@intel.com> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: kbuild test robot Cc: kbuild-all@01.org, Andrew Morton , Linux Memory Management List On 12/10/2015 06:05 PM, kbuild test robot wrote: > tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master > head: 8225f4e85cb03daea14661380745886ce01fd83a > commit: 0dd08f12cafd7868be55bc10ebcd4ea13880860b [5266/5426] UBSAN: run-time undefined behavior sanity checker > config: x86_64-randconfig-s5-12102221 (attached as .config) > reproduce: > git checkout 0dd08f12cafd7868be55bc10ebcd4ea13880860b > # save the attached .config to linux build tree > make ARCH=x86_64 > > Note: it may well be a FALSE warning. FWIW you are at least aware of it now. > http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings > This is certainly a false positive. It seems that UBSAN could make gcc more stupid and increase number of maybe-uninitialized false-positives. > All warnings (new ones prefixed by >>): > > arch/x86/kernel/cpu/mcheck/mce.c: In function 'do_machine_check': >>> arch/x86/kernel/cpu/mcheck/mce.c:884:5: warning: 'order' may be used uninitialized in this function [-Wmaybe-uninitialized] > if (order == 1) { > ^ > arch/x86/kernel/cpu/mcheck/mce.c:984:6: note: 'order' was declared here > int order; -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org