This is a note to let you know that I've just added the patch titled
Allow stack to grow up to address space limit
to the 4.9-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:
allow-stack-to-grow-up-to-address-space-limit.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From bd726c90b6b8ce87602208701b208a208e6d5600 Mon Sep 17 00:00:00 2001
From: Helge Deller <deller@xxxxxx>
Date: Mon, 19 Jun 2017 17:34:05 +0200
Subject: Allow stack to grow up to address space limit
From: Helge Deller <deller@xxxxxx>
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 <deller@xxxxxx>
Acked-by: Hugh Dickins <hughd@xxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/mmap.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2224,16 +2224,19 @@ 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))
Patches currently in stable-queue which might be from deller@xxxxxx are
queue-4.9/allow-stack-to-grow-up-to-address-space-limit.patch
queue-4.9/mm-larger-stack-guard-gap-between-vmas.patch