thp: pmd_trans_huge migrate bugcheck
No pmd_trans_huge should ever materialize in migration ptes areas, because
we split the hugepage before migration ptes are instantiated.
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/memory.c b/mm/memory.c
index c1a80e0..12ee1ea 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1305,6 +1305,10 @@
goto out;
}
if (pmd_trans_huge(*pmd)) {
+ if (flags & FOLL_SPLIT) {
+ split_huge_page_pmd(mm, pmd);
+ goto split_fallthrough;
+ }
spin_lock(&mm->page_table_lock);
if (likely(pmd_trans_huge(*pmd))) {
if (unlikely(pmd_trans_splitting(*pmd))) {
@@ -1320,6 +1324,7 @@
spin_unlock(&mm->page_table_lock);
/* fall through */
}
+split_fallthrough:
if (unlikely(pmd_bad(*pmd)))
goto no_page_table;