slub: convert SLAB_DEBUG_FREE to SLAB_CONSISTENCY_CHECKS
SLAB_DEBUG_FREE allows expensive consistency checks at free to be turned
on or off. Expand its use to be able to turn off all consistency
checks. This gives a nice speed up if you only want features such as
poisoning or tracing.
Credit to Mathias Krause for the original work which inspired this
series
Signed-off-by: Laura Abbott <labbott@fedoraproject.org>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Mathias Krause <minipli@googlemail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/Documentation/vm/slub.txt b/Documentation/vm/slub.txt
index f0d3409..8465241 100644
--- a/Documentation/vm/slub.txt
+++ b/Documentation/vm/slub.txt
@@ -35,8 +35,8 @@
Enable options only for select slabs
Possible debug options are
- F Sanity checks on (enables SLAB_DEBUG_FREE. Sorry
- SLAB legacy issues)
+ F Sanity checks on (enables SLAB_DEBUG_CONSISTENCY_CHECKS
+ Sorry SLAB legacy issues)
Z Red zoning
P Poisoning (object and padding)
U User tracking (free and alloc)
diff --git a/include/linux/slab.h b/include/linux/slab.h
index 5d49f0c..e4b5687 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -20,7 +20,7 @@
* Flags to pass to kmem_cache_create().
* The ones marked DEBUG are only valid if CONFIG_DEBUG_SLAB is set.
*/
-#define SLAB_DEBUG_FREE 0x00000100UL /* DEBUG: Perform (expensive) checks on free */
+#define SLAB_CONSISTENCY_CHECKS 0x00000100UL /* DEBUG: Perform (expensive) checks on alloc/free */
#define SLAB_RED_ZONE 0x00000400UL /* DEBUG: Red zone objs in a cache */
#define SLAB_POISON 0x00000800UL /* DEBUG: Poison objects */
#define SLAB_HWCACHE_ALIGN 0x00002000UL /* Align objs on cache lines */
diff --git a/mm/slab.h b/mm/slab.h
index e880bbe..b793436 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -125,7 +125,7 @@
#define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
#elif defined(CONFIG_SLUB_DEBUG)
#define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
- SLAB_TRACE | SLAB_DEBUG_FREE)
+ SLAB_TRACE | SLAB_CONSISTENCY_CHECKS)
#else
#define SLAB_DEBUG_FLAGS (0)
#endif
@@ -311,7 +311,8 @@
* to not do even the assignment. In that case, slab_equal_or_root
* will also be a constant.
*/
- if (!memcg_kmem_enabled() && !unlikely(s->flags & SLAB_DEBUG_FREE))
+ if (!memcg_kmem_enabled() &&
+ !unlikely(s->flags & SLAB_CONSISTENCY_CHECKS))
return s;
page = virt_to_head_page(x);
diff --git a/mm/slub.c b/mm/slub.c
index 744d29b..9cde663 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -160,7 +160,7 @@
*/
#define MAX_PARTIAL 10
-#define DEBUG_DEFAULT_FLAGS (SLAB_DEBUG_FREE | SLAB_RED_ZONE | \
+#define DEBUG_DEFAULT_FLAGS (SLAB_CONSISTENCY_CHECKS | SLAB_RED_ZONE | \
SLAB_POISON | SLAB_STORE_USER)
/*
@@ -1007,20 +1007,32 @@
init_tracking(s, object);
}
-static noinline int alloc_debug_processing(struct kmem_cache *s,
+static inline int alloc_consistency_checks(struct kmem_cache *s,
struct page *page,
void *object, unsigned long addr)
{
if (!check_slab(s, page))
- goto bad;
+ return 0;
if (!check_valid_pointer(s, page, object)) {
object_err(s, page, object, "Freelist Pointer check fails");
- goto bad;
+ return 0;
}
if (!check_object(s, page, object, SLUB_RED_INACTIVE))
- goto bad;
+ return 0;
+
+ return 1;
+}
+
+static noinline int alloc_debug_processing(struct kmem_cache *s,
+ struct page *page,
+ void *object, unsigned long addr)
+{
+ if (s->flags & SLAB_CONSISTENCY_CHECKS) {
+ if (!alloc_consistency_checks(s, page, object, addr))
+ goto bad;
+ }
/* Success perform special debug activities for allocs */
if (s->flags & SLAB_STORE_USER)
@@ -1043,6 +1055,38 @@
return 0;
}
+static inline int free_consistency_checks(struct kmem_cache *s,
+ struct page *page, void *object, unsigned long addr)
+{
+ if (!check_valid_pointer(s, page, object)) {
+ slab_err(s, page, "Invalid object pointer 0x%p", object);
+ return 0;
+ }
+
+ if (on_freelist(s, page, object)) {
+ object_err(s, page, object, "Object already free");
+ return 0;
+ }
+
+ if (!check_object(s, page, object, SLUB_RED_ACTIVE))
+ return 0;
+
+ if (unlikely(s != page->slab_cache)) {
+ if (!PageSlab(page)) {
+ slab_err(s, page, "Attempt to free object(0x%p) "
+ "outside of slab", object);
+ } else if (!page->slab_cache) {
+ pr_err("SLUB <none>: no slab for object 0x%p.\n",
+ object);
+ dump_stack();
+ } else
+ object_err(s, page, object,
+ "page slab pointer corrupt.");
+ return 0;
+ }
+ return 1;
+}
+
/* Supports checking bulk free of a constructed freelist */
static noinline int free_debug_processing(
struct kmem_cache *s, struct page *page,
@@ -1058,37 +1102,17 @@
spin_lock_irqsave(&n->list_lock, flags);
slab_lock(page);
- if (!check_slab(s, page))
- goto out;
+ if (s->flags & SLAB_CONSISTENCY_CHECKS) {
+ if (!check_slab(s, page))
+ goto out;
+ }
next_object:
cnt++;
- if (!check_valid_pointer(s, page, object)) {
- slab_err(s, page, "Invalid object pointer 0x%p", object);
- goto out;
- }
-
- if (on_freelist(s, page, object)) {
- object_err(s, page, object, "Object already free");
- goto out;
- }
-
- if (!check_object(s, page, object, SLUB_RED_ACTIVE))
- goto out;
-
- if (unlikely(s != page->slab_cache)) {
- if (!PageSlab(page)) {
- slab_err(s, page, "Attempt to free object(0x%p) "
- "outside of slab", object);
- } else if (!page->slab_cache) {
- pr_err("SLUB <none>: no slab for object 0x%p.\n",
- object);
- dump_stack();
- } else
- object_err(s, page, object,
- "page slab pointer corrupt.");
- goto out;
+ if (s->flags & SLAB_CONSISTENCY_CHECKS) {
+ if (!free_consistency_checks(s, page, object, addr))
+ goto out;
}
if (s->flags & SLAB_STORE_USER)
@@ -1145,7 +1169,7 @@
for (; *str && *str != ','; str++) {
switch (tolower(*str)) {
case 'f':
- slub_debug |= SLAB_DEBUG_FREE;
+ slub_debug |= SLAB_CONSISTENCY_CHECKS;
break;
case 'z':
slub_debug |= SLAB_RED_ZONE;
@@ -1449,7 +1473,7 @@
int order = compound_order(page);
int pages = 1 << order;
- if (kmem_cache_debug(s)) {
+ if (s->flags & SLAB_CONSISTENCY_CHECKS) {
void *p;
slab_pad_check(s, page);
@@ -4769,16 +4793,16 @@
static ssize_t sanity_checks_show(struct kmem_cache *s, char *buf)
{
- return sprintf(buf, "%d\n", !!(s->flags & SLAB_DEBUG_FREE));
+ return sprintf(buf, "%d\n", !!(s->flags & SLAB_CONSISTENCY_CHECKS));
}
static ssize_t sanity_checks_store(struct kmem_cache *s,
const char *buf, size_t length)
{
- s->flags &= ~SLAB_DEBUG_FREE;
+ s->flags &= ~SLAB_CONSISTENCY_CHECKS;
if (buf[0] == '1') {
s->flags &= ~__CMPXCHG_DOUBLE;
- s->flags |= SLAB_DEBUG_FREE;
+ s->flags |= SLAB_CONSISTENCY_CHECKS;
}
return length;
}
@@ -5313,7 +5337,7 @@
*p++ = 'd';
if (s->flags & SLAB_RECLAIM_ACCOUNT)
*p++ = 'a';
- if (s->flags & SLAB_DEBUG_FREE)
+ if (s->flags & SLAB_CONSISTENCY_CHECKS)
*p++ = 'F';
if (!(s->flags & SLAB_NOTRACK))
*p++ = 't';
diff --git a/tools/vm/slabinfo.c b/tools/vm/slabinfo.c
index 86e698d..1889163 100644
--- a/tools/vm/slabinfo.c
+++ b/tools/vm/slabinfo.c
@@ -135,7 +135,7 @@
"\nValid debug options (FZPUT may be combined)\n"
"a / A Switch on all debug options (=FZUP)\n"
"- Switch off all debug options\n"
- "f / F Sanity Checks (SLAB_DEBUG_FREE)\n"
+ "f / F Sanity Checks (SLAB_CONSISTENCY_CHECKS)\n"
"z / Z Redzoning\n"
"p / P Poisoning\n"
"u / U Tracking\n"