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-rw-r--r--mm/mmap.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/mm/mmap.c b/mm/mmap.c
index 68b9ad2ef1d6..906ed402f7ca 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1536,9 +1536,14 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address)
1536 * vma->vm_start/vm_end cannot change under us because the caller 1536 * vma->vm_start/vm_end cannot change under us because the caller
1537 * is required to hold the mmap_sem in read mode. We need the 1537 * is required to hold the mmap_sem in read mode. We need the
1538 * anon_vma lock to serialize against concurrent expand_stacks. 1538 * anon_vma lock to serialize against concurrent expand_stacks.
1539 * Also guard against wrapping around to address 0.
1539 */ 1540 */
1540 address += 4 + PAGE_SIZE - 1; 1541 if (address < PAGE_ALIGN(address+4))
1541 address &= PAGE_MASK; 1542 address = PAGE_ALIGN(address+4);
1543 else {
1544 anon_vma_unlock(vma);
1545 return -ENOMEM;
1546 }
1542 error = 0; 1547 error = 0;
1543 1548
1544 /* Somebody else might have raced and expanded it already */ 1549 /* Somebody else might have raced and expanded it already */