mm: lock a vma before stack expansion

With recent changes necessitating mmap_lock to be held for write while
expanding a stack, per-VMA locks should follow the same rules and be
write-locked to prevent page faults into the VMA being expanded. Add
the necessary locking.

Signed-off-by: Suren Baghdasaryan <>
Signed-off-by: Linus Torvalds <>
1 file changed