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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 03E86C433FF for ; Sat, 10 Aug 2019 20:49:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D30D420B7C for ; Sat, 10 Aug 2019 20:49:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726785AbfHJUso (ORCPT ); Sat, 10 Aug 2019 16:48:44 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:54792 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726792AbfHJUoA (ORCPT ); Sat, 10 Aug 2019 16:44:00 -0400 Received: from [192.168.4.242] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1hwYDV-00053a-Ko; Sat, 10 Aug 2019 21:43:57 +0100 Received: from ben by deadeye with local (Exim 4.92) (envelope-from ) id 1hwYDN-0003ic-Rh; Sat, 10 Aug 2019 21:43:49 +0100 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, Denis Kirjanov , "Peter Zijlstra" , "H. Peter Anvin" , "Andy Lutomirski" , "Borislav Petkov" , "Brian Gerst" , "Linus Torvalds" , "Josh Poimboeuf" , "Wanpeng Li" , "Ingo Molnar" , "Denys Vlasenko" , "Thomas Gleixner" Date: Sat, 10 Aug 2019 21:40:07 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 124/157] x86/entry/64: Fix context tracking state warning when load_gs_index fails In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.242 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 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 3.16.72-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Wanpeng Li commit 2fa5f04f85730d0c4f49f984b7efeb4f8d5bd1fc upstream. This warning: WARNING: CPU: 0 PID: 3331 at arch/x86/entry/common.c:45 enter_from_user_mode+0x32/0x50 CPU: 0 PID: 3331 Comm: ldt_gdt_64 Not tainted 4.8.0-rc7+ #13 Call Trace: dump_stack+0x99/0xd0 __warn+0xd1/0xf0 warn_slowpath_null+0x1d/0x20 enter_from_user_mode+0x32/0x50 error_entry+0x6d/0xc0 ? general_protection+0x12/0x30 ? native_load_gs_index+0xd/0x20 ? do_set_thread_area+0x19c/0x1f0 SyS_set_thread_area+0x24/0x30 do_int80_syscall_32+0x7c/0x220 entry_INT80_compat+0x38/0x50 ... can be reproduced by running the GS testcase of the ldt_gdt test unit in the x86 selftests. do_int80_syscall_32() will call enter_form_user_mode() to convert context tracking state from user state to kernel state. The load_gs_index() call can fail with user gsbase, gsbase will be fixed up and proceed if this happen. However, enter_from_user_mode() will be called again in the fixed up path though it is context tracking kernel state currently. This patch fixes it by just fixing up gsbase and telling lockdep that IRQs are off once load_gs_index() failed with user gsbase. Signed-off-by: Wanpeng Li Acked-by: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1475197266-3440-1-git-send-email-wanpeng.li@hotmail.com Signed-off-by: Ingo Molnar [bwh: Backported to 3.16 as dependency of commit 18ec54fdd6d1 "x86/speculation: Prepare entry code for Spectre v1 swapgs mitigations": - Adjust filename] Signed-off-by: Ben Hutchings --- arch/x86/kernel/entry_64.S | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/arch/x86/kernel/entry_64.S +++ b/arch/x86/kernel/entry_64.S @@ -1447,7 +1447,6 @@ ENTRY(error_entry) testl $3,CS+8(%rsp) jz .Lerror_kernelspace -.Lerror_entry_from_usermode_swapgs: /* * We entered from user mode or we're pretending to have entered * from user mode due to an IRET fault. @@ -1480,7 +1479,8 @@ ENTRY(error_entry) * gsbase and proceed. We'll fix up the exception and land in * gs_change's error handler with kernel gsbase. */ - jmp .Lerror_entry_from_usermode_swapgs + SWAPGS + jmp .Lerror_entry_done .Lbstep_iret: /* Fix truncated RIP */