From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932916AbcGOMCp (ORCPT ); Fri, 15 Jul 2016 08:02:45 -0400 Received: from terminus.zytor.com ([198.137.202.10]:55882 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932565AbcGOMCn (ORCPT ); Fri, 15 Jul 2016 08:02:43 -0400 Date: Fri, 15 Jul 2016 05:01:51 -0700 From: tip-bot for Andy Lutomirski Message-ID: Cc: luto@kernel.org, mingo@kernel.org, peterz@infradead.org, brgerst@gmail.com, dvlasenk@redhat.com, bp@alien8.de, tglx@linutronix.de, linux-kernel@vger.kernel.org, jpoimboe@redhat.com, hpa@zytor.com, torvalds@linux-foundation.org Reply-To: torvalds@linux-foundation.org, jpoimboe@redhat.com, hpa@zytor.com, bp@alien8.de, linux-kernel@vger.kernel.org, tglx@linutronix.de, dvlasenk@redhat.com, brgerst@gmail.com, mingo@kernel.org, peterz@infradead.org, luto@kernel.org In-Reply-To: <4650d7674185f165ed8fdf9ac4c5c35c5c179ba8.1468527351.git.luto@kernel.org> References: <4650d7674185f165ed8fdf9ac4c5c35c5c179ba8.1468527351.git.luto@kernel.org> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/mm] x86/mm/64: In vmalloc_fault(), use CR3 instead of current->active_mm Git-Commit-ID: 46aea3873401836abb7f01200e7946e7d518b359 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: 46aea3873401836abb7f01200e7946e7d518b359 Gitweb: http://git.kernel.org/tip/46aea3873401836abb7f01200e7946e7d518b359 Author: Andy Lutomirski AuthorDate: Thu, 14 Jul 2016 13:22:54 -0700 Committer: Ingo Molnar CommitDate: Fri, 15 Jul 2016 10:26:27 +0200 x86/mm/64: In vmalloc_fault(), use CR3 instead of current->active_mm If we get a vmalloc fault while current->active_mm->pgd doesn't match CR3, we'll crash without this change. I've seen this failure mode on heavily instrumented kernels with virtually mapped stacks. Signed-off-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/4650d7674185f165ed8fdf9ac4c5c35c5c179ba8.1468527351.git.luto@kernel.org Signed-off-by: Ingo Molnar --- arch/x86/mm/fault.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 7d1fa7c..ca44e2e 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -439,7 +439,7 @@ static noinline int vmalloc_fault(unsigned long address) * happen within a race in page table update. In the later * case just flush: */ - pgd = pgd_offset(current->active_mm, address); + pgd = (pgd_t *)__va(read_cr3()) + pgd_index(address); pgd_ref = pgd_offset_k(address); if (pgd_none(*pgd_ref)) return -1;