mm/hugetlb.c: add NULL check of return value of huge_pte_offset
mm/hugetlb.c: add NULL check of return value of huge_pte_offset

huge_pte_offset() could return NULL, so we need NULL check to avoid
potential NULL pointer dereferences.

Signed-off-by: Naoya Horiguchi <8e7a128cd0264d3269a891fb3e87507c2985f8af@ah.jp.nec.com>
Cc: Mel Gorman <39ea6a09710987173e32e37c86918024a0f441c1@suse.de>
Cc: Sasha Levin <e642b69ed2fc111e09ffdc37feb733a52253340d@oracle.com>
Cc: Kirill A. Shutemov <eec72676ad9a62f2727dfed6d270d98c0d02adec@linux.intel.com>
Cc: Aneesh Kumar K.V <f511f818e8a0748edef6b9ee378967da9ed0c78f@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <5c1e68b099950c134891f0b6e179498a8ebe9cf9@linux-foundation.org>
Signed-off-by: Linus Torvalds <69652caca27c8b940640ad396ab71f93cacec34f@linux-foundation.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs