On Fri, Aug 23, 2019 at 03:17:53PM -0700, Ralph Campbell wrote: > Signed-off-by: Ralph Campbell <rcampbell@xxxxxxxxxx> > mm/hmm.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/mm/hmm.c b/mm/hmm.c > index 29371485fe94..4882b83aeccb 100644 > +++ b/mm/hmm.c > @@ -292,6 +292,9 @@ static int hmm_vma_walk_hole_(unsigned long addr, unsigned long end, > hmm_vma_walk->last = addr; > i = (addr - range->start) >> PAGE_SHIFT; > > + if (write_fault && walk->vma && !(walk->vma->vm_flags & VM_WRITE)) > + return -EPERM; Can walk->vma be NULL here? hmm_vma_do_fault() touches it unconditionally. Jason
