From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933546AbcI3MIN (ORCPT ); Fri, 30 Sep 2016 08:08:13 -0400 Received: from terminus.zytor.com ([198.137.202.10]:45392 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932311AbcI3MIL (ORCPT ); Fri, 30 Sep 2016 08:08:11 -0400 Date: Fri, 30 Sep 2016 05:07:12 -0700 From: tip-bot for Wanpeng Li Message-ID: Cc: wanpeng.li@hotmail.com, linux-kernel@vger.kernel.org, hpa@zytor.com, bp@alien8.de, torvalds@linux-foundation.org, luto@kernel.org, mingo@kernel.org, dvlasenk@redhat.com, jpoimboe@redhat.com, brgerst@gmail.com, tglx@linutronix.de, peterz@infradead.org Reply-To: wanpeng.li@hotmail.com, linux-kernel@vger.kernel.org, hpa@zytor.com, bp@alien8.de, torvalds@linux-foundation.org, luto@kernel.org, mingo@kernel.org, dvlasenk@redhat.com, jpoimboe@redhat.com, brgerst@gmail.com, peterz@infradead.org, tglx@linutronix.de In-Reply-To: <1475197266-3440-1-git-send-email-wanpeng.li@hotmail.com> References: <1475197266-3440-1-git-send-email-wanpeng.li@hotmail.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/urgent] x86/entry/64: Fix context tracking state warning when load_gs_index fails Git-Commit-ID: 2fa5f04f85730d0c4f49f984b7efeb4f8d5bd1fc 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 List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 2fa5f04f85730d0c4f49f984b7efeb4f8d5bd1fc Gitweb: http://git.kernel.org/tip/2fa5f04f85730d0c4f49f984b7efeb4f8d5bd1fc Author: Wanpeng Li AuthorDate: Fri, 30 Sep 2016 09:01:06 +0800 Committer: Ingo Molnar CommitDate: Fri, 30 Sep 2016 13:53:12 +0200 x86/entry/64: Fix context tracking state warning when load_gs_index fails 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 --- arch/x86/entry/entry_64.S | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index d172c61..02fff3e 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -1002,7 +1002,6 @@ ENTRY(error_entry) testb $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. @@ -1045,7 +1044,8 @@ ENTRY(error_entry) * gsbase and proceed. We'll fix up the exception and land in * .Lgs_change's error handler with kernel gsbase. */ - jmp .Lerror_entry_from_usermode_swapgs + SWAPGS + jmp .Lerror_entry_done .Lbstep_iret: /* Fix truncated RIP */