From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AB5ABC43441 for ; Thu, 22 Nov 2018 10:11:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7582A20866 for ; Thu, 22 Nov 2018 10:11:56 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7582A20866 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=zytor.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2393937AbeKVUuk (ORCPT ); Thu, 22 Nov 2018 15:50:40 -0500 Received: from terminus.zytor.com ([198.137.202.136]:52319 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387936AbeKVUuk (ORCPT ); Thu, 22 Nov 2018 15:50:40 -0500 Received: from terminus.zytor.com (localhost [127.0.0.1]) by terminus.zytor.com (8.15.2/8.15.2) with ESMTPS id wAMAASHs3743740 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Thu, 22 Nov 2018 02:10:28 -0800 Received: (from tipbot@localhost) by terminus.zytor.com (8.15.2/8.15.2/Submit) id wAMAASnr3743737; Thu, 22 Nov 2018 02:10:28 -0800 Date: Thu, 22 Nov 2018 02:10:28 -0800 X-Authentication-Warning: terminus.zytor.com: tipbot set sender to tipbot@zytor.com using -f From: tip-bot for Andy Lutomirski Message-ID: Cc: peterz@infradead.org, mingo@kernel.org, hpa@zytor.com, bp@alien8.de, riel@surriel.com, yu-cheng.yu@intel.com, torvalds@linux-foundation.org, tglx@linutronix.de, luto@kernel.org, dave.hansen@linux.intel.com, linux-kernel@vger.kernel.org Reply-To: peterz@infradead.org, mingo@kernel.org, hpa@zytor.com, bp@alien8.de, riel@surriel.com, yu-cheng.yu@intel.com, torvalds@linux-foundation.org, tglx@linutronix.de, luto@kernel.org, dave.hansen@linux.intel.com, linux-kernel@vger.kernel.org In-Reply-To: <9999f151d72ff352265f3274c5ab3a4105090f49.1542841400.git.luto@kernel.org> References: <9999f151d72ff352265f3274c5ab3a4105090f49.1542841400.git.luto@kernel.org> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/mm] x86/fault: Don't try to recover from an implicit supervisor access Git-Commit-ID: ebb53e2597e2dc7637ab213df006e99681b6ee25 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 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: ebb53e2597e2dc7637ab213df006e99681b6ee25 Gitweb: https://git.kernel.org/tip/ebb53e2597e2dc7637ab213df006e99681b6ee25 Author: Andy Lutomirski AuthorDate: Wed, 21 Nov 2018 15:11:23 -0800 Committer: Ingo Molnar CommitDate: Thu, 22 Nov 2018 09:23:00 +0100 x86/fault: Don't try to recover from an implicit supervisor access This avoids a situation in which we attempt to apply various fixups that are not intended to handle implicit supervisor accesses from user mode if we screw up in a way that causes this type of fault. Signed-off-by: Andy Lutomirski Cc: Borislav Petkov Cc: Dave Hansen Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Rik van Riel Cc: Thomas Gleixner Cc: Yu-cheng Yu Link: http://lkml.kernel.org/r/9999f151d72ff352265f3274c5ab3a4105090f49.1542841400.git.luto@kernel.org Signed-off-by: Ingo Molnar --- arch/x86/mm/fault.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 82881bc5feef..ca38bd0472f2 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -653,6 +653,15 @@ no_context(struct pt_regs *regs, unsigned long error_code, unsigned long flags; int sig; + if (user_mode(regs)) { + /* + * This is an implicit supervisor-mode access from user + * mode. Bypass all the kernel-mode recovery code and just + * OOPS. + */ + goto oops; + } + /* Are we prepared to handle this kernel fault? */ if (fixup_exception(regs, X86_TRAP_PF, error_code, address)) { /* @@ -738,6 +747,7 @@ no_context(struct pt_regs *regs, unsigned long error_code, if (IS_ENABLED(CONFIG_EFI)) efi_recover_from_page_fault(address); +oops: /* * Oops. The kernel tried to access some bad page. We'll have to * terminate things with extreme prejudice: