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| author | Helge Deller <deller@gmx.de> | 2017-06-19 17:34:05 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-06-21 11:07:18 -0700 |
| commit | bd726c90b6b8ce87602208701b208a208e6d5600 (patch) | |
| tree | 4108143f648b9f0bffed509c0afffbe933036f2b | |
| parent | f4cb767d76cf7ee72f97dd76f6cfa6c76a5edc89 (diff) | |
| download | lwn-bd726c90b6b8ce87602208701b208a208e6d5600.tar.gz lwn-bd726c90b6b8ce87602208701b208a208e6d5600.zip | |
Allow stack to grow up to address space limit
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>
| -rw-r--r-- | mm/mmap.c | 13 |
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)) |