tree 5b17c58699eed9c7440812f0f2f29f4c80972973
parent 14d1a55cd26f1860f837f37ae42520c7c13b1347
author Andrea Arcangeli <aarcange@redhat.com> 1294962436 -0800
committer Linus Torvalds <torvalds@linux-foundation.org> 1294968767 -0800

thp: fix memory-failure hugetlbfs vs THP collision

hugetlbfs was changed to allow memory failure to migrate the hugetlbfs
pages and that broke THP as split_huge_page was then called on hugetlbfs
pages too.

compound_head/order was also run unsafe on THP pages that can be splitted
at any time.

All compound_head() invocations in memory-failure.c that are run on pages
that aren't pinned and that can be freed and reused from under us (while
compound_head is running) are buggy because compound_head can return a
dangling pointer, but I'm not fixing this as this is a generic
memory-failure bug not specific to THP but it applies to hugetlbfs too, so
I can fix it later after THP is merged upstream.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>