kmemleak: Add the slab memory allocation/freeing hooks
This patch adds the callbacks to kmemleak_(alloc|free) functions from
the slab allocator. The patch also adds the SLAB_NOLEAKTRACE flag to
avoid recursive calls to kmemleak when it allocates its own data
structures.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Pekka Enberg <penberg@cs.helsinki.fi>
diff --git a/mm/slab.c b/mm/slab.c
index f85831d..859067f 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -107,6 +107,7 @@
#include <linux/string.h>
#include <linux/uaccess.h>
#include <linux/nodemask.h>
+#include <linux/kmemleak.h>
#include <linux/mempolicy.h>
#include <linux/mutex.h>
#include <linux/fault-inject.h>
@@ -178,13 +179,13 @@
SLAB_STORE_USER | \
SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \
SLAB_DESTROY_BY_RCU | SLAB_MEM_SPREAD | \
- SLAB_DEBUG_OBJECTS)
+ SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE)
#else
# define CREATE_MASK (SLAB_HWCACHE_ALIGN | \
SLAB_CACHE_DMA | \
SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \
SLAB_DESTROY_BY_RCU | SLAB_MEM_SPREAD | \
- SLAB_DEBUG_OBJECTS)
+ SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE)
#endif
/*
@@ -964,6 +965,14 @@
struct array_cache *nc = NULL;
nc = kmalloc_node(memsize, GFP_KERNEL, node);
+ /*
+ * The array_cache structures contain pointers to free object.
+ * However, when such objects are allocated or transfered to another
+ * cache the pointers are not cleared and they could be counted as
+ * valid references during a kmemleak scan. Therefore, kmemleak must
+ * not scan such objects.
+ */
+ kmemleak_no_scan(nc);
if (nc) {
nc->avail = 0;
nc->limit = entries;
@@ -2621,6 +2630,14 @@
/* Slab management obj is off-slab. */
slabp = kmem_cache_alloc_node(cachep->slabp_cache,
local_flags, nodeid);
+ /*
+ * If the first object in the slab is leaked (it's allocated
+ * but no one has a reference to it), we want to make sure
+ * kmemleak does not treat the ->s_mem pointer as a reference
+ * to the object. Otherwise we will not report the leak.
+ */
+ kmemleak_scan_area(slabp, offsetof(struct slab, list),
+ sizeof(struct list_head), local_flags);
if (!slabp)
return NULL;
} else {
@@ -3141,6 +3158,12 @@
STATS_INC_ALLOCMISS(cachep);
objp = cache_alloc_refill(cachep, flags);
}
+ /*
+ * To avoid a false negative, if an object that is in one of the
+ * per-CPU caches is leaked, we need to make sure kmemleak doesn't
+ * treat the array pointers as a reference to the object.
+ */
+ kmemleak_erase(&ac->entry[ac->avail]);
return objp;
}
@@ -3360,6 +3383,8 @@
out:
local_irq_restore(save_flags);
ptr = cache_alloc_debugcheck_after(cachep, flags, ptr, caller);
+ kmemleak_alloc_recursive(ptr, obj_size(cachep), 1, cachep->flags,
+ flags);
if (unlikely((flags & __GFP_ZERO) && ptr))
memset(ptr, 0, obj_size(cachep));
@@ -3415,6 +3440,8 @@
objp = __do_cache_alloc(cachep, flags);
local_irq_restore(save_flags);
objp = cache_alloc_debugcheck_after(cachep, flags, objp, caller);
+ kmemleak_alloc_recursive(objp, obj_size(cachep), 1, cachep->flags,
+ flags);
prefetchw(objp);
if (unlikely((flags & __GFP_ZERO) && objp))
@@ -3530,6 +3557,7 @@
struct array_cache *ac = cpu_cache_get(cachep);
check_irq_off();
+ kmemleak_free_recursive(objp, cachep->flags);
objp = cache_free_debugcheck(cachep, objp, __builtin_return_address(0));
/*