From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:50690 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751083AbdFVAzO (ORCPT ); Wed, 21 Jun 2017 20:55:14 -0400 Subject: Patch "mm: fix new crash in unmapped_area_topdown()" has been added to the 4.4-stable tree To: hughd@google.com, davej@codemonkey.org.uk, gregkh@linuxfoundation.org, mhocko@suse.com, torvalds@linux-foundation.org Cc: , From: Date: Thu, 22 Jun 2017 08:54:48 +0800 Message-ID: <14980928881321@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled mm: fix new crash in unmapped_area_topdown() to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: mm-fix-new-crash-in-unmapped_area_topdown.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From f4cb767d76cf7ee72f97dd76f6cfa6c76a5edc89 Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Tue, 20 Jun 2017 02:10:44 -0700 Subject: mm: fix new crash in unmapped_area_topdown() From: Hugh Dickins commit f4cb767d76cf7ee72f97dd76f6cfa6c76a5edc89 upstream. Trinity gets kernel BUG at mm/mmap.c:1963! in about 3 minutes of mmap testing. That's the VM_BUG_ON(gap_end < gap_start) at the end of unmapped_area_topdown(). Linus points out how MAP_FIXED (which does not have to respect our stack guard gap intentions) could result in gap_end below gap_start there. Fix that, and the similar case in its alternative, unmapped_area(). Fixes: 1be7107fbe18 ("mm: larger stack guard gap, between vmas") Reported-by: Dave Jones Debugged-by: Linus Torvalds Signed-off-by: Hugh Dickins Acked-by: Michal Hocko Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/mmap.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1771,7 +1771,8 @@ check_current: /* Check if current node has a suitable gap */ if (gap_start > high_limit) return -ENOMEM; - if (gap_end >= low_limit && gap_end - gap_start >= length) + if (gap_end >= low_limit && + gap_end > gap_start && gap_end - gap_start >= length) goto found; /* Visit right subtree if it looks promising */ @@ -1874,7 +1875,8 @@ check_current: gap_end = vm_start_gap(vma); if (gap_end < low_limit) return -ENOMEM; - if (gap_start <= high_limit && gap_end - gap_start >= length) + if (gap_start <= high_limit && + gap_end > gap_start && gap_end - gap_start >= length) goto found; /* Visit left subtree if it looks promising */ Patches currently in stable-queue which might be from hughd@google.com are queue-4.4/mm-fix-new-crash-in-unmapped_area_topdown.patch queue-4.4/allow-stack-to-grow-up-to-address-space-limit.patch queue-4.4/mm-larger-stack-guard-gap-between-vmas.patch