diff mbox series

[3/5] kmemleak: account for tagged pointers when calculating pointer range

Message ID df99854703d906040a7a898ac892167e3ffe90d9.1549921721.git.andreyknvl@google.com (mailing list archive)
State New, archived
Headers show
Series kasan: more tag based mode fixes | expand

Commit Message

Andrey Konovalov Feb. 11, 2019, 9:59 p.m. UTC 
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.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 mm/kmemleak.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

Comments

Catalin Marinas Feb. 15, 2019, 2:05 p.m. UTC | #1 
On Mon, Feb 11, 2019 at 10:59:52PM +0100, Andrey Konovalov wrote:
> 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.
> 
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
diff mbox series

Patch

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;
 
 		/*