diff options
| -rw-r--r-- | mm/rmap.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/mm/rmap.c b/mm/rmap.c index 6657000b18d4..ab16c96efdfb 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1054,8 +1054,14 @@ static void __page_set_anon_rmap(struct page *page, if (!exclusive) anon_vma = anon_vma->root; + /* + * page_idle does a lockless/optimistic rmap scan on page->mapping. + * Make sure the compiler doesn't split the stores of anon_vma and + * the PAGE_MAPPING_ANON type identifier, otherwise the rmap code + * could mistake the mapping for a struct address_space and crash. + */ anon_vma = (void *) anon_vma + PAGE_MAPPING_ANON; - page->mapping = (struct address_space *) anon_vma; + WRITE_ONCE(page->mapping, (struct address_space *) anon_vma); page->index = linear_page_index(vma, address); } |