diff options
| -rw-r--r-- | mm/mmap.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/mm/mmap.c b/mm/mmap.c index 68b9ad2ef1d..906ed402f7c 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1536,9 +1536,14 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address) * vma->vm_start/vm_end cannot change under us because the caller * is required to hold the mmap_sem in read mode. We need the * anon_vma lock to serialize against concurrent expand_stacks. + * Also guard against wrapping around to address 0. */ - address += 4 + PAGE_SIZE - 1; - address &= PAGE_MASK; + if (address < PAGE_ALIGN(address+4)) + address = PAGE_ALIGN(address+4); + else { + anon_vma_unlock(vma); + return -ENOMEM; + } error = 0; /* Somebody else might have raced and expanded it already */ |