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-rw-r--r--mm/mmap.c13
1 files changed, 8 insertions, 5 deletions
diff --git a/mm/mmap.c b/mm/mmap.c
index 290b77d9a01e..a5e3dcd75e79 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2230,16 +2230,19 @@ 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))