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Commit d5cff635 authored by Catalin Marinas's avatar Catalin Marinas
Browse files

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: default avatarCatalin Marinas <catalin.marinas@arm.com>
Reviewed-by: default avatarPekka Enberg <penberg@cs.helsinki.fi>
parent 04f70336

include/linux/slab.h

+2 −0
Original line number Diff line number Diff line
@@ -62,6 +62,8 @@ 
# define SLAB_DEBUG_OBJECTS	0x00000000UL

#endif



#define SLAB_NOLEAKTRACE	0x00800000UL	/* Avoid kmemleak tracing */



/* The following flags affect the page allocator grouping pages by mobility */

#define SLAB_RECLAIM_ACCOUNT	0x00020000UL		/* Objects are reclaimable */

#define SLAB_TEMPORARY		SLAB_RECLAIM_ACCOUNT	/* Objects are short-lived */

mm/slab.c

+30 −2
Original line number Diff line number Diff line
@@ -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 @@ static struct array_cache *alloc_arraycache(int node, int entries, 
	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 @@ static struct slab *alloc_slabmgmt(struct kmem_cache *cachep, void *objp, 
		/* 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 @@ static inline void *____cache_alloc(struct kmem_cache *cachep, gfp_t flags) 
		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 @@ __cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid, 
  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 @@ __cache_alloc(struct kmem_cache *cachep, gfp_t flags, void *caller) 
	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 @@ static inline void __cache_free(struct kmem_cache *cachep, void *objp) 
	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));



	/*