Commit a2f77575 authored by Andrey Konovalov's avatar Andrey Konovalov Committed by Linus Torvalds
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kmemleak: account for tagged pointers when calculating pointer range 

kmemleak keeps two global variables, min_addr and max_addr, which store
the range of valid (encountered by kmemleak) pointer values, which it
later uses to speed up pointer lookup when scanning blocks.

With tagged pointers this range will get bigger than it needs to be.  This
patch makes kmemleak untag pointers before saving them to min_addr and
max_addr and when performing a lookup.

Link: http://lkml.kernel.org/r/16e887d442986ab87fe87a755815ad92fa431a5f.1550066133.git.andreyknvl@google.com


Signed-off-by: default avatarAndrey Konovalov <andreyknvl@google.com>
Tested-by: default avatarQian Cai <cai@lca.pw>
Acked-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgeniy Stepanov <eugenis@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kostya Serebryany <kcc@google.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 53128245

mm/kmemleak.c

+7 −3
Original line number Diff line number Diff line
@@ -574,6 +574,7 @@ static struct kmemleak_object *create_object(unsigned long ptr, size_t size, 
	unsigned long flags;

	struct kmemleak_object *object, *parent;

	struct rb_node **link, *rb_parent;

	unsigned long untagged_ptr;



	object = kmem_cache_alloc(object_cache, gfp_kmemleak_mask(gfp));

	if (!object) {
@@ -619,8 +620,9 @@ static struct kmemleak_object *create_object(unsigned long ptr, size_t size, 


	write_lock_irqsave(&kmemleak_lock, flags);



	min_addr = min(min_addr, ptr);

	max_addr = max(max_addr, ptr + size);

	untagged_ptr = (unsigned long)kasan_reset_tag((void *)ptr);

	min_addr = min(min_addr, untagged_ptr);

	max_addr = max(max_addr, untagged_ptr + size);

	link = &object_tree_root.rb_node;

	rb_parent = NULL;

	while (*link) {
@@ -1333,6 +1335,7 @@ static void scan_block(void *_start, void *_end, 
	unsigned long *start = PTR_ALIGN(_start, BYTES_PER_POINTER);

	unsigned long *end = _end - (BYTES_PER_POINTER - 1);

	unsigned long flags;

	unsigned long untagged_ptr;



	read_lock_irqsave(&kmemleak_lock, flags);

	for (ptr = start; ptr < end; ptr++) {
@@ -1347,7 +1350,8 @@ static void scan_block(void *_start, void *_end, 
		pointer = *ptr;

		kasan_enable_current();



		if (pointer < min_addr || pointer >= max_addr)

		untagged_ptr = (unsigned long)kasan_reset_tag((void *)pointer);

		if (untagged_ptr < min_addr || untagged_ptr >= max_addr)

			continue;



		/*

mm/slab.h

+1 −0
Original line number Diff line number Diff line
@@ -438,6 +438,7 @@ static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags, 
	flags &= gfp_allowed_mask;

	for (i = 0; i < size; i++) {

		p[i] = kasan_slab_alloc(s, p[i], flags);

		/* As p[i] might get tagged, call kmemleak hook after KASAN. */

		kmemleak_alloc_recursive(p[i], s->object_size, 1,

					 s->flags, flags);

	}

mm/slab_common.c

+1 −0
Original line number Diff line number Diff line
@@ -1229,6 +1229,7 @@ void *kmalloc_order(size_t size, gfp_t flags, unsigned int order) 
	page = alloc_pages(flags, order);

	ret = page ? page_address(page) : NULL;

	ret = kasan_kmalloc_large(ret, size, flags);

	/* As ret might get tagged, call kmemleak hook after KASAN. */

	kmemleak_alloc(ret, size, 1, flags);

	return ret;

}

mm/slub.c

+1 −0
Original line number Diff line number Diff line
@@ -1375,6 +1375,7 @@ static inline void dec_slabs_node(struct kmem_cache *s, int node, 
static inline void *kmalloc_large_node_hook(void *ptr, size_t size, gfp_t flags)

{

	ptr = kasan_kmalloc_large(ptr, size, flags);

	/* As ptr might get tagged, call kmemleak hook after KASAN. */

	kmemleak_alloc(ptr, size, 1, flags);

	return ptr;

}

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