From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752896AbdF0LM4 (ORCPT ); Tue, 27 Jun 2017 07:12:56 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:34837 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752668AbdF0LMi (ORCPT ); Tue, 27 Jun 2017 07:12:38 -0400 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, "Helge Deller" , "Hugh Dickins" , "Linus Torvalds" Date: Tue, 27 Jun 2017 12:10:34 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 3/7] Allow stack to grow up to address space limit In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 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 3.16.45-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Helge Deller commit bd726c90b6b8ce87602208701b208a208e6d5600 upstream. Fix expand_upwards() on architectures with an upward-growing stack (parisc, metag and partly IA-64) to allow the stack to reliably grow exactly up to the address space limit given by TASK_SIZE. Signed-off-by: Helge Deller Acked-by: Hugh Dickins Signed-off-by: Linus Torvalds Signed-off-by: Ben Hutchings --- mm/mmap.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2139,16 +2139,19 @@ int expand_upwards(struct vm_area_struct if (!(vma->vm_flags & VM_GROWSUP)) return -EFAULT; - /* Guard against wrapping around to address 0. */ + /* Guard against exceeding limits of the address space. */ address &= PAGE_MASK; - address += PAGE_SIZE; - if (!address) + if (address >= TASK_SIZE) return -ENOMEM; + address += PAGE_SIZE; /* Enforce stack_guard_gap */ gap_addr = address + stack_guard_gap; - if (gap_addr < address) - return -ENOMEM; + + /* Guard against overflow */ + if (gap_addr < address || gap_addr > TASK_SIZE) + gap_addr = TASK_SIZE; + next = vma->vm_next; if (next && next->vm_start < gap_addr) { if (!(next->vm_flags & VM_GROWSUP))