From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-678564-1519838844-2-14437379348220696976 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 0.249, 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='uk', 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=1519838844; b=f43bJarbh/qhdwz6AbIB1rO1DqHUVQek0BP3rwZo5qyAANc zTGi/BHJD4PifLhDkZj9XiWHkq3wdgqrPDwW3RPCc5Akcr/0QZ8+zGobSTnzTUUe COChTgGAWMaGMy9FM1s8pSqtzEo2eh0ae8INo69Lj5Op7kbdjyMbDdg3dZZkKmA0 r1P550p/n1Pxyg+v1xbpjpLDGnIBmYzCeeBFIjesMTqX5IL7ZwjDK7TnYe65PlOm GWY7xq2xlps1JUE+9V8BKILVRhT4pSdl+e/2Mrcq0/dZ+QJw9mgCV2yDllE6T3CI sKljFIhhWwua5rwjC2wOdBN7u6+cjVbU/vtIn6Q== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=content-type:content-transfer-encoding :mime-version:from:to:cc:date:message-id:subject:in-reply-to :sender:list-id; s=arctest; t=1519838844; bh=5EQFM77MaU+WmjvdVL0 2dGW+m7l7HtrRJDfKgjLBiXo=; b=XKVfGpJPBISycu0EO2H3g/Ei6H7DrcG22Lq 9TkvUIxcwkdh3Tk4a2FMEYpjKr8QF1ersJe4cv5ZpxHe6ldgJiMuPTWor9Sft4UN WfIpTqLIjnJ1lvK8dnf8VfDWTKqKWa0ZWI9maxmqgaSYNlqlYksk4wLMR4EjbNIG 3Q9bHBP0SCbHyi/ZdnEqLVUeGmnD/w943ARsDFto26MRlJqDr2SU0hkmdeu7jpQu XiBftkE7+DIiRdS7+bTQKlHz7/4NjioJMwDz0STg4E3NPk/aFHi5kCeHs+1ZwGqQ rY+wMmchT4UA2z1nPbn7QL8nvVnvFBHqFZRrBvtwzHXHzA9Qs2g== ARC-Authentication-Results: i=1; mx2.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=decadent.org.uk; 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=decadent.org.uk header.result=pass header_is_org_domain=yes Authentication-Results: mx2.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=decadent.org.uk; 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=decadent.org.uk header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753483AbeB1RZH (ORCPT ); Wed, 28 Feb 2018 12:25:07 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:33297 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932616AbeB1PWP (ORCPT ); Wed, 28 Feb 2018 10:22:15 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Andy Lutomirski" , "Linus Torvalds" , "Dave Hansen" , "Jiri Kosina" Date: Wed, 28 Feb 2018 15:20:22 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 072/140] kbuild: add '-fno-stack-check' to kernel build options In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false 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: 3.2.100-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Linus Torvalds commit 3ce120b16cc548472f80cf8644f90eda958cf1b6 upstream. It appears that hardened gentoo enables "-fstack-check" by default for gcc. That doesn't work _at_all_ for the kernel, because the kernel stack doesn't act like a user stack at all: it's much smaller, and it doesn't auto-expand on use. So the extra "probe one page below the stack" code generated by -fstack-check just breaks the kernel in horrible ways, causing infinite double faults etc. [ I have to say, that the particular code gcc generates looks very stupid even for user space where it works, but that's a separate issue. ] Reported-and-tested-by: Alexander Tsoy Reported-and-tested-by: Toralf Förster Cc: Dave Hansen Cc: Jiri Kosina Cc: Andy Lutomirski Signed-off-by: Linus Torvalds Signed-off-by: Ben Hutchings --- Makefile | 3 +++ 1 file changed, 3 insertions(+) --- a/Makefile +++ b/Makefile @@ -631,6 +631,9 @@ KBUILD_CFLAGS += $(call cc-disable-warni # disable invalid "can't wrap" optimizations for signed / pointers KBUILD_CFLAGS += $(call cc-option,-fno-strict-overflow) +# Make sure -fstack-check isn't enabled (like gentoo apparently did) +KBUILD_CFLAGS += $(call cc-option,-fno-stack-check,) + # conserve stack if available KBUILD_CFLAGS += $(call cc-option,-fconserve-stack)