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Subject[PATCH v2 3/4] mm: kmemleak: handle address stored in object based on its type
Date
Treat the address stored in object in different way according
to its type:

- Only use kasan_reset_tag for virtual address
- Only update min_addr and max_addr for virtual address
- Convert physical address to virtual address in scan_object

Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Patrick Wang <patrick.wang.shcn@gmail.com>
---
mm/kmemleak.c | 34 ++++++++++++++++++++++++----------
1 file changed, 24 insertions(+), 10 deletions(-)

diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index 218144392446..246a70b7218f 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -297,7 +297,9 @@ static void hex_dump_object(struct seq_file *seq,
warn_or_seq_printf(seq, " hex dump (first %zu bytes):\n", len);
kasan_disable_current();
warn_or_seq_hex_dump(seq, DUMP_PREFIX_NONE, HEX_ROW_SIZE,
- HEX_GROUP_SIZE, kasan_reset_tag((void *)ptr), len, HEX_ASCII);
+ HEX_GROUP_SIZE, object->flags & OBJECT_PHYS ? ptr :
+ kasan_reset_tag((void *)ptr),
+ len, HEX_ASCII);
kasan_enable_current();
}

@@ -389,14 +391,15 @@ static struct kmemleak_object *lookup_object(unsigned long ptr, int alias,
{
struct rb_node *rb = is_phys ? object_phys_tree_root.rb_node :
object_tree_root.rb_node;
- unsigned long untagged_ptr = (unsigned long)kasan_reset_tag((void *)ptr);
+ unsigned long untagged_ptr = is_phys ? ptr : (unsigned long)kasan_reset_tag((void *)ptr);

while (rb) {
struct kmemleak_object *object;
unsigned long untagged_objp;

object = rb_entry(rb, struct kmemleak_object, rb_node);
- untagged_objp = (unsigned long)kasan_reset_tag((void *)object->pointer);
+ untagged_objp = is_phys ? object->pointer :
+ (unsigned long)kasan_reset_tag((void *)object->pointer);

if (untagged_ptr < untagged_objp)
rb = object->rb_node.rb_left;
@@ -643,16 +646,19 @@ static struct kmemleak_object *create_object(unsigned long ptr, size_t size,

raw_spin_lock_irqsave(&kmemleak_lock, flags);

- untagged_ptr = (unsigned long)kasan_reset_tag((void *)ptr);
- min_addr = min(min_addr, untagged_ptr);
- max_addr = max(max_addr, untagged_ptr + size);
+ untagged_ptr = is_phys ? ptr : (unsigned long)kasan_reset_tag((void *)ptr);
+ if (!is_phys) {
+ min_addr = min(min_addr, untagged_ptr);
+ max_addr = max(max_addr, untagged_ptr + size);
+ }
link = is_phys ? &object_phys_tree_root.rb_node :
&object_tree_root.rb_node;
rb_parent = NULL;
while (*link) {
rb_parent = *link;
parent = rb_entry(rb_parent, struct kmemleak_object, rb_node);
- untagged_objp = (unsigned long)kasan_reset_tag((void *)parent->pointer);
+ untagged_objp = is_phys ? parent->pointer :
+ (unsigned long)kasan_reset_tag((void *)parent->pointer);
if (untagged_ptr + size <= untagged_objp)
link = &parent->rb_node.rb_left;
else if (untagged_objp + parent->size <= untagged_ptr)
@@ -1202,7 +1208,9 @@ static bool update_checksum(struct kmemleak_object *object)

kasan_disable_current();
kcsan_disable_current();
- object->checksum = crc32(0, kasan_reset_tag((void *)object->pointer), object->size);
+ object->checksum = crc32(0, object->flags & OBJECT_PHYS ? (void *)object->pointer :
+ kasan_reset_tag((void *)object->pointer),
+ object->size);
kasan_enable_current();
kcsan_enable_current();

@@ -1353,6 +1361,7 @@ static void scan_object(struct kmemleak_object *object)
{
struct kmemleak_scan_area *area;
unsigned long flags;
+ void *obj_ptr;

/*
* Once the object->lock is acquired, the corresponding memory block
@@ -1364,10 +1373,15 @@ static void scan_object(struct kmemleak_object *object)
if (!(object->flags & OBJECT_ALLOCATED))
/* already freed object */
goto out;
+
+ obj_ptr = object->flags & OBJECT_PHYS ?
+ __va((void *)object->pointer) :
+ (void *)object->pointer;
+
if (hlist_empty(&object->area_list) ||
object->flags & OBJECT_FULL_SCAN) {
- void *start = (void *)object->pointer;
- void *end = (void *)(object->pointer + object->size);
+ void *start = obj_ptr;
+ void *end = obj_ptr + object->size;
void *next;

do {
--
2.25.1
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