From 5c5e3b33b7cb959a401f823707bee006caadd76e Mon Sep 17 00:00:00 2001 From: Shiyong Li Date: Mon, 12 Apr 2010 13:48:21 +0800 Subject: [PATCH] slab: Fix missing DEBUG_SLAB last user Even with SLAB_RED_ZONE and SLAB_STORE_USER enabled, kernel would NOT store redzone and last user data around allocated memory space if "arch cache line > sizeof(unsigned long long)". As a result, last user information is unexpectedly MISSED while dumping slab corruption log. This fix makes sure that redzone and last user tags get stored unless the required alignment breaks redzone's. Signed-off-by: Shiyong Li Signed-off-by: Pekka Enberg --- mm/slab.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/mm/slab.c b/mm/slab.c index bac0f4fcc216..525c66466469 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -2220,8 +2220,8 @@ kmem_cache_create (const char *name, size_t size, size_t align, if (ralign < align) { ralign = align; } - /* disable debug if necessary */ - if (ralign > __alignof__(unsigned long long)) + /* disable debug if not aligning with REDZONE_ALIGN */ + if (ralign & (__alignof__(unsigned long long) - 1)) flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER); /* * 4) Store it. @@ -2247,8 +2247,8 @@ kmem_cache_create (const char *name, size_t size, size_t align, */ if (flags & SLAB_RED_ZONE) { /* add space for red zone words */ - cachep->obj_offset += sizeof(unsigned long long); - size += 2 * sizeof(unsigned long long); + cachep->obj_offset += align; + size += align + sizeof(unsigned long long); } if (flags & SLAB_STORE_USER) { /* user store requires one word storage behind the end of -- 2.30.2