powerpc/booke: Only check for hugetlb in flush if vma != NULL
authorScott Wood <scottwood@freescale.com>
Fri, 22 Nov 2013 00:26:42 +0000 (18:26 -0600)
committerScott Wood <scottwood@freescale.com>
Fri, 22 Nov 2013 22:57:29 +0000 (16:57 -0600)
commitd742aa152f27448d39ce65fb829e396d10cd63a9
tree51b626c0dc20c3c2992987929860a6d8c19a3003
parent53567cf3c28d11f58927e5d4946a744ec2fbf06e
powerpc/booke: Only check for hugetlb in flush if vma != NULL

And in flush_hugetlb_page(), don't check whether vma is NULL after
we've already dereferenced it.

This was found by Dan using static analysis as described here:
https://lists.ozlabs.org/pipermail/linuxppc-dev/2013-November/113161.html

We currently get away with this because the callers that currently pass
NULL for vma seem to be 32-bit-only (e.g. highmem, and
CONFIG_DEBUG_PGALLOC in pgtable_32.c)  Hugetlb is currently 64-bit only,
so we never saw a NULL vma here.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
arch/powerpc/mm/hugetlbpage-book3e.c
arch/powerpc/mm/tlb_nohash.c