diff options
| -rw-r--r-- | include/linux/poison.h | 9 | ||||
| -rw-r--r-- | mm/hugetlb.c | 5 |
2 files changed, 13 insertions, 1 deletions
diff --git a/include/linux/poison.h b/include/linux/poison.h index 2110a81c5e2..34066ffd893 100644 --- a/include/linux/poison.h +++ b/include/linux/poison.h @@ -48,6 +48,15 @@ #define POISON_FREE 0x6b /* for use-after-free poisoning */ #define POISON_END 0xa5 /* end-byte of poisoning */ +/********** mm/hugetlb.c **********/ +/* + * Private mappings of hugetlb pages use this poisoned value for + * page->mapping. The core VM should not be doing anything with this mapping + * but futex requires the existence of some page->mapping value even though it + * is unused if PAGE_MAPPING_ANON is set. + */ +#define HUGETLB_POISON ((void *)(0x00300300 + POISON_POINTER_DELTA + PAGE_MAPPING_ANON)) + /********** arch/$ARCH/mm/init.c **********/ #define POISON_FREE_INITMEM 0xcc diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 5d7601b0287..220c22acbe0 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -545,6 +545,7 @@ static void free_huge_page(struct page *page) mapping = (struct address_space *) page_private(page); set_page_private(page, 0); + page->mapping = NULL; BUG_ON(page_count(page)); INIT_LIST_HEAD(&page->lru); @@ -2095,8 +2096,10 @@ retry: spin_lock(&inode->i_lock); inode->i_blocks += blocks_per_huge_page(h); spin_unlock(&inode->i_lock); - } else + } else { lock_page(page); + page->mapping = HUGETLB_POISON; + } } /* |