From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-564561-1519836079-2-1115995332774918015 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=1519836078; b=hAoBRd9Qvb4KTCj98V0rTu6fQFcvdmuctlP7nr9h/aJExY8 GXyA++53CV/OF0xnXw//ID6b7FFlRU4QukZBtRP4TiHjg/vVPVGwnd39LJWKnFDM CMA47YnBBQaEisU6MEG9EdjkEyB/QBuwkMQ5t/QskFW31jpBIG5GuMd4rLC4FzF8 YojFyWsFtuVqhbb+N59jZ7rG1nkAXNxK4bCmD9p7hOFUivKSpKteHxEi236Ep82s W714F6aFOf6y4Y65tThq/HRnZAg7ckR465hxxep7f0PlfxprRgLK5Q7Zq004WiaZ aFTz4yEl6x1MIcZ7ynLapb5yBFsEAzWVjzu9p/w== 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=1519836078; bh=DudJn+aIZ+bWruXXxZ2 VabkSgS+sfAqJXC/RBpqppys=; b=gRGSFFI8Gkxl5CfffLLLCQ/JLtb4F8HaoIX z1ZPaz7hZ6oOwIZxGglHX5zZJhGBGkTEp0TO7NpAAHYIYh2FlxEE+VNIZt3aAkwk E4Ni9GLCp5XQ6OnwL6qFvhQ+X8xwnqWyNTLF+AuuaPZRcqQB74wqZJZ2A1eNWjAH GGYeAf7qg3aCiuJ7bJIUMrh/AhBsFVCtpEeW19BI6ue27ZchxjzFeD/qA86MZxv1 u5z2ILcq0aoAwUBqGT5OSjRDugNQUsKOKu+tPrp7tRW5AkouJyB3UTo25xmqrQeH stXbKxCFDupCXXegmbzu5tHr/bl5m4EIfU+cOCtgrjSeAq+w4OA== ARC-Authentication-Results: i=1; mx4.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: mx4.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 S932407AbeB1QDh (ORCPT ); Wed, 28 Feb 2018 11:03:37 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:34775 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932318AbeB1QDf (ORCPT ); Wed, 28 Feb 2018 11:03:35 -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, "Linus Torvalds" , "Jiri Kosina" , "Dave Hansen" , "Andy Lutomirski" Date: Wed, 28 Feb 2018 15:20:18 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 152/254] 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: 3.16.55-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 @@ -736,6 +736,9 @@ 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)