From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755871AbcETKOi (ORCPT ); Fri, 20 May 2016 06:14:38 -0400 Received: from terminus.zytor.com ([198.137.202.10]:54268 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755823AbcETKOb (ORCPT ); Fri, 20 May 2016 06:14:31 -0400 Date: Fri, 20 May 2016 03:13:28 -0700 From: tip-bot for Andy Lutomirski Message-ID: Cc: gorcunov@gmail.com, brgerst@gmail.com, peterz@infradead.org, bp@alien8.de, oleg@redhat.com, dvlasenk@redhat.com, luto@amacapital.net, mingo@kernel.org, 0x7f454c46@gmail.com, xemul@parallels.com, linux-kernel@vger.kernel.org, hpa@zytor.com, luto@kernel.org, b7.10110111@gmail.com, torvalds@linux-foundation.org, tglx@linutronix.de Reply-To: luto@kernel.org, linux-kernel@vger.kernel.org, hpa@zytor.com, torvalds@linux-foundation.org, b7.10110111@gmail.com, tglx@linutronix.de, 0x7f454c46@gmail.com, mingo@kernel.org, xemul@parallels.com, dvlasenk@redhat.com, luto@amacapital.net, bp@alien8.de, gorcunov@gmail.com, brgerst@gmail.com, peterz@infradead.org, oleg@redhat.com In-Reply-To: <1242fb23b0d05c3069dbf5758ac55d26bc114bef.1462914565.git.luto@kernel.org> References: <1242fb23b0d05c3069dbf5758ac55d26bc114bef.1462914565.git.luto@kernel.org> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/urgent] x86/mm: Switch from TASK_SIZE to TASK_SIZE_MAX in the page fault code Git-Commit-ID: dc4fac84f8e66b147921ebdc385e767d5def7422 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: dc4fac84f8e66b147921ebdc385e767d5def7422 Gitweb: http://git.kernel.org/tip/dc4fac84f8e66b147921ebdc385e767d5def7422 Author: Andy Lutomirski AuthorDate: Tue, 10 May 2016 14:10:29 -0700 Committer: Ingo Molnar CommitDate: Fri, 20 May 2016 09:10:03 +0200 x86/mm: Switch from TASK_SIZE to TASK_SIZE_MAX in the page fault code x86's page fault handlers had two TASK_SIZE uses that should have been TASK_SIZE_MAX. I don't think that either one had a visible effect, but this makes the code clearer and should save a few bytes of text. (And I eventually want to eradicate TASK_SIZE. This will help.) Reported-by: Cyrill Gorcunov Signed-off-by: Andy Lutomirski Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: Dmitry Safonov <0x7f454c46@gmail.com> Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Pavel Emelyanov Cc: Peter Zijlstra Cc: Ruslan Kabatsayev Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1242fb23b0d05c3069dbf5758ac55d26bc114bef.1462914565.git.luto@kernel.org Signed-off-by: Ingo Molnar --- arch/x86/mm/fault.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 5ce1ed0..7d1fa7c 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -292,7 +292,7 @@ void vmalloc_sync_all(void) return; for (address = VMALLOC_START & PMD_MASK; - address >= TASK_SIZE && address < FIXADDR_TOP; + address >= TASK_SIZE_MAX && address < FIXADDR_TOP; address += PMD_SIZE) { struct page *page; @@ -854,8 +854,13 @@ __bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code, return; } #endif - /* Kernel addresses are always protection faults: */ - if (address >= TASK_SIZE) + + /* + * To avoid leaking information about the kernel page table + * layout, pretend that user-mode accesses to kernel addresses + * are always protection faults. + */ + if (address >= TASK_SIZE_MAX) error_code |= PF_PROT; if (likely(show_unhandled_signals))