Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934790AbbGHJqo (ORCPT ); Wed, 8 Jul 2015 05:46:44 -0400 Received: from terminus.zytor.com ([198.137.202.10]:46836 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934478AbbGHJqj (ORCPT ); Wed, 8 Jul 2015 05:46:39 -0400 Date: Wed, 8 Jul 2015 02:45:39 -0700 From: tip-bot for Andy Lutomirski Message-ID: Cc: brgerst@gmail.com, oleg@redhat.com, hpa@zytor.com, torvalds@linux-foundation.org, keescook@chromium.org, bp@alien8.de, dvlasenk@redhat.com, peterz@infradead.org, luto@kernel.org, arjan@linux.intel.com, tglx@linutronix.de, luto@amacapital.net, linux-kernel@vger.kernel.org, mingo@kernel.org Reply-To: dvlasenk@redhat.com, peterz@infradead.org, luto@kernel.org, arjan@linux.intel.com, tglx@linutronix.de, linux-kernel@vger.kernel.org, luto@amacapital.net, mingo@kernel.org, brgerst@gmail.com, oleg@redhat.com, hpa@zytor.com, bp@alien8.de, torvalds@linux-foundation.org, keescook@chromium.org In-Reply-To: <23d4709cee2fe92c32d41b99c7a3c1823725925a.1436312944.git.luto@kernel.org> References: <23d4709cee2fe92c32d41b99c7a3c1823725925a.1436312944.git.luto@kernel.org> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/asm] x86/kconfig/32: Mark CONFIG_VM86 as BROKEN Git-Commit-ID: 0b02e20767a3b4d843d2c58cf031d9e31f60e39d 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 Content-Length: 2951 Lines: 74 Commit-ID: 0b02e20767a3b4d843d2c58cf031d9e31f60e39d Gitweb: http://git.kernel.org/tip/0b02e20767a3b4d843d2c58cf031d9e31f60e39d Author: Andy Lutomirski AuthorDate: Tue, 7 Jul 2015 18:25:56 -0700 Committer: Ingo Molnar CommitDate: Wed, 8 Jul 2015 11:04:45 +0200 x86/kconfig/32: Mark CONFIG_VM86 as BROKEN VM86 is entirely broken if ptrace, syscall auditing, or NOHZ_FULL is in use. The code is a big undocumented mess, it's a real PITA to test, and it looks like a big chunk of vm86_32.c is dead code. It also plays awful games with the entry asm. No one should be using it anyway. Use DOSBOX or KVM instead. Mark it BROKEN. I want to remove some (obviously incorrect) exit asm that it depends on, and I don't want to figure out how to run severely obsolete programs just to test something that no one uses for anything other than exploits anyway. Signed-off-by: Andy Lutomirski Acked-by: Arjan van de Ven Cc: # Backport it as far back as possible Cc: Andy Lutomirski Cc: Arjan van de Ven Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Kees Cook Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/23d4709cee2fe92c32d41b99c7a3c1823725925a.1436312944.git.luto@kernel.org Signed-off-by: Ingo Molnar --- arch/x86/Kconfig | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index aa94fd0..a7648f9b 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -997,8 +997,8 @@ config X86_THERMAL_VECTOR depends on X86_MCE_INTEL config VM86 - bool "Enable VM86 support" if EXPERT - default y + bool "Enable VM86 support" if BROKEN + default n depends on X86_32 ---help--- This option is required by programs like DOSEMU to run @@ -1006,6 +1006,12 @@ config VM86 be needed by software like XFree86 to initialize some video cards via BIOS. Disabling this option saves about 6K. + Linux's VM86 support is poorly maintained, essentially never + tested by upstream kernel developers, has quite a few known + bugs, and is probably full of security holes. The only thing + that appears to use it is DOSEMU, and DOSBOX and KVM are + better options these days. Don't enable it. + config X86_16BIT bool "Enable support for 16-bit segments" if EXPERT default y -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/