mm/huge_memory: replace VM_NO_THP VM_BUG_ON with actual VMA check
authorKonstantin Khlebnikov <koct9i@gmail.com>
Thu, 28 Apr 2016 23:18:32 +0000 (16:18 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 29 Apr 2016 02:34:04 +0000 (19:34 -0700)
commit3486b85a29c1741db99d0c522211c82d2b7a56d0
tree4f4cae93c4107744a09445f880fc39a14f85ebec
parent314e9b75b3f673a61ecbf0bba401830bc7dfe121
mm/huge_memory: replace VM_NO_THP VM_BUG_ON with actual VMA check

Khugepaged detects own VMAs by checking vm_file and vm_ops but this way
it cannot distinguish private /dev/zero mappings from other special
mappings like /dev/hpet which has no vm_ops and popultes PTEs in mmap.

This fixes false-positive VM_BUG_ON and prevents installing THP where
they are not expected.

Link: http://lkml.kernel.org/r/CACT4Y+ZmuZMV5CjSFOeXviwQdABAgT7T+StKfTqan9YDtgEi5g@mail.gmail.com
Fixes: 78f11a255749 ("mm: thp: fix /dev/zero MAP_PRIVATE and vm_flags cleanups")
Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/huge_memory.c