From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755785AbbBQCjs (ORCPT ); Mon, 16 Feb 2015 21:39:48 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:33667 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751847AbbBQBu4 (ORCPT ); Mon, 16 Feb 2015 20:50:56 -0500 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, "Jan Engelhardt" , linux-arch@vger.kernel.org, "Heiko Carstens" , "Linus Torvalds" Date: Tue, 17 Feb 2015 01:46:53 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 135/152] vm: make stack guard page errors return VM_FAULT_SIGSEGV rather than SIGBUS In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.249 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.67-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Linus Torvalds commit 9c145c56d0c8a0b62e48c8d71e055ad0fb2012ba upstream. The stack guard page error case has long incorrectly caused a SIGBUS rather than a SIGSEGV, but nobody actually noticed until commit fee7e49d4514 ("mm: propagate error from stack expansion even for guard page") because that error case was never actually triggered in any normal situations. Now that we actually report the error, people noticed the wrong signal that resulted. So far, only the test suite of libsigsegv seems to have actually cared, but there are real applications that use libsigsegv, so let's not wait for any of those to break. Reported-and-tested-by: Takashi Iwai Tested-by: Jan Engelhardt Acked-by: Heiko Carstens # "s390 still compiles and boots" Cc: linux-arch@vger.kernel.org Signed-off-by: Linus Torvalds Signed-off-by: Ben Hutchings --- mm/memory.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/mm/memory.c +++ b/mm/memory.c @@ -3155,7 +3155,7 @@ static int do_anonymous_page(struct mm_s /* Check if we need to add a guard page to the stack */ if (check_stack_guard_page(vma, address) < 0) - return VM_FAULT_SIGBUS; + return VM_FAULT_SIGSEGV; /* Use the zero-page for reads */ if (!(flags & FAULT_FLAG_WRITE)) {