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authorAndrea Arcangeli <aarcange@redhat.com>2011-01-14 02:47:16 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2011-01-14 04:32:47 +0300
commit91600e9e592e48736e630851c83da2ad6bf0e91f (patch)
tree5b17c58699eed9c7440812f0f2f29f4c80972973
parent14d1a55cd26f1860f837f37ae42520c7c13b1347 (diff)
downloadlinux-91600e9e592e48736e630851c83da2ad6bf0e91f.tar.xz
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>
-rw-r--r--mm/memory-failure.c2
-rw-r--r--mm/rmap.c2
2 files changed, 2 insertions, 2 deletions
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 6a283cc9317c..1b43d0ffff65 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -386,7 +386,7 @@ static void collect_procs_anon(struct page *page, struct list_head *to_kill,
struct task_struct *tsk;
struct anon_vma *av;
- if (unlikely(split_huge_page(page)))
+ if (!PageHuge(page) && unlikely(split_huge_page(page)))
return;
read_lock(&tasklist_lock);
av = page_lock_anon_vma(page);
diff --git a/mm/rmap.c b/mm/rmap.c
index 3825ae4bc32f..c30f33854f97 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1430,7 +1430,7 @@ int try_to_unmap(struct page *page, enum ttu_flags flags)
int ret;
BUG_ON(!PageLocked(page));
- BUG_ON(PageTransHuge(page));
+ VM_BUG_ON(!PageHuge(page) && PageTransHuge(page));
if (unlikely(PageKsm(page)))
ret = try_to_unmap_ksm(page, flags);