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authorAndrey Konovalov <andreyknvl@google.com>2019-02-20 22:19:16 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2019-02-21 09:01:00 -0800
commita2f775751d964e638818487544fa8320180d106e (patch)
tree8f57aa384bdf7f56a130c853ccb257b048269205
parent53128245b43daad600d9fe72940206570e064112 (diff)
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: Andrey Konovalov <andreyknvl@google.com> Tested-by: Qian Cai <cai@lca.pw> Acked-by: Catalin 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: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/kmemleak.c10
-rw-r--r--mm/slab.h1
-rw-r--r--mm/slab_common.c1
-rw-r--r--mm/slub.c1
4 files changed, 10 insertions, 3 deletions
diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index f9d9dc250428..707fa5579f66 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -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;
/*
diff --git a/mm/slab.h b/mm/slab.h
index 638ea1b25d39..384105318779 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -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);
}
diff --git a/mm/slab_common.c b/mm/slab_common.c
index fe524c8d0246..f9d89c1b5977 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -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;
}
diff --git a/mm/slub.c b/mm/slub.c
index 4a3d7686902f..f5a451c49190 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -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;
}