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authorHelge Deller <deller@gmx.de>2017-06-19 17:34:05 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-06-26 07:10:54 +0200
commitc6aeba66df8743478d7b9f64fa76d88ed4100c67 (patch)
treef8814ab294520465e67f84fec3306654a498acf4
parentd4712eb79b17d85c9e354efa2d3156ce50736128 (diff)
Allow stack to grow up to address space limit
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@gmx.de> Acked-by: Hugh Dickins <hughd@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--mm/mmap.c13
1 files changed, 8 insertions, 5 deletions
diff --git a/mm/mmap.c b/mm/mmap.c
index 14ccc949921f..ff12e23d0b50 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2175,16 +2175,19 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address)
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))