From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752108AbaBMQSi (ORCPT ); Thu, 13 Feb 2014 11:18:38 -0500 Received: from terminus.zytor.com ([198.137.202.10]:40571 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751881AbaBMQSg (ORCPT ); Thu, 13 Feb 2014 11:18:36 -0500 Date: Thu, 13 Feb 2014 08:18:24 -0800 From: "tip-bot for H. Peter Anvin" Message-ID: Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@kernel.org, tglx@linutronix.de, fengguang.wu@intel.com, hpa@linux.intel.com Reply-To: mingo@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org, tglx@linutronix.de, hpa@linux.intel.com, fengguang.wu@intel.com In-Reply-To: <20140213124550.GA30497@localhost> References: <20140213124550.GA30497@localhost> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/urgent] x86, smap: smap_violation() is bogus if CONFIG_X86_SMAP is off Git-Commit-ID: af0c23df96fbc16089e8eda4b94b7d69b845f81e X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.1 (terminus.zytor.com [127.0.0.1]); Thu, 13 Feb 2014 08:18:30 -0800 (PST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: af0c23df96fbc16089e8eda4b94b7d69b845f81e Gitweb: http://git.kernel.org/tip/af0c23df96fbc16089e8eda4b94b7d69b845f81e Author: H. Peter Anvin AuthorDate: Thu, 13 Feb 2014 07:46:04 -0800 Committer: H. Peter Anvin CommitDate: Thu, 13 Feb 2014 08:08:58 -0800 x86, smap: smap_violation() is bogus if CONFIG_X86_SMAP is off If CONFIG_X86_SMAP is disabled, smap_violation() tests for conditions which are incorrect (as the AC flag doesn't matter), causing spurious faults. The dynamic disabling of SMAP (nosmap on the command line) is fine because it disables X86_FEATURE_SMAP, therefore causing the static_cpu_has() to return false. Found by Fengguang Wu's test system. [ v2: use IS_ENABLED() instead of #ifdef ] Reported-by: Fengguang Wu Link: http://lkml.kernel.org/r/20140213124550.GA30497@localhost Signed-off-by: H. Peter Anvin Cc: # v3.7+ --- arch/x86/mm/fault.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 9d591c8..824b445 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -1087,7 +1087,7 @@ __do_page_fault(struct pt_regs *regs, unsigned long error_code) if (unlikely(error_code & PF_RSVD)) pgtable_bad(regs, error_code, address); - if (static_cpu_has(X86_FEATURE_SMAP)) { + if (IS_ENABLED(CONFIG_X86_SMAP) && static_cpu_has(X86_FEATURE_SMAP)) { if (unlikely(smap_violation(error_code, regs))) { bad_area_nosemaphore(regs, error_code, address); return;