[PATCH 1/2] Revert "mm/kmemleak: move the initialisation of object to __link_object"

From: Liu Shixin
Date: Wed Nov 15 2023 - 02:23:26 EST


Move the initialisation of object back to__alloc_object() because
set_track_prepare() attempt to acquire zone->lock(spinlocks) while
__link_object is holding kmemleak_lock(raw_spinlocks). This is not
right for RT mode.

This reverts commit 245245c2fffd0050772a3f30ba50e2be92537a32.

Signed-off-by: Liu Shixin <liushixin2@xxxxxxxxxx>
---
mm/kmemleak.c | 36 +++++++++++++++++++-----------------
1 file changed, 19 insertions(+), 17 deletions(-)

diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index 1eacca03bedd..22bab3738a9e 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -642,32 +642,16 @@ static struct kmemleak_object *__alloc_object(gfp_t gfp)
if (!object) {
pr_warn("Cannot allocate a kmemleak_object structure\n");
kmemleak_disable();
+ return NULL;
}

- return object;
-}
-
-static int __link_object(struct kmemleak_object *object, unsigned long ptr,
- size_t size, int min_count, bool is_phys)
-{
-
- struct kmemleak_object *parent;
- struct rb_node **link, *rb_parent;
- unsigned long untagged_ptr;
- unsigned long untagged_objp;
-
INIT_LIST_HEAD(&object->object_list);
INIT_LIST_HEAD(&object->gray_list);
INIT_HLIST_HEAD(&object->area_list);
raw_spin_lock_init(&object->lock);
atomic_set(&object->use_count, 1);
- object->flags = OBJECT_ALLOCATED | (is_phys ? OBJECT_PHYS : 0);
- object->pointer = ptr;
- object->size = kfence_ksize((void *)ptr) ?: size;
object->excess_ref = 0;
- object->min_count = min_count;
object->count = 0; /* white color initially */
- object->jiffies = jiffies;
object->checksum = 0;
object->del_state = 0;

@@ -692,6 +676,24 @@ static int __link_object(struct kmemleak_object *object, unsigned long ptr,
/* kernel backtrace */
object->trace_handle = set_track_prepare();

+ return object;
+}
+
+static int __link_object(struct kmemleak_object *object, unsigned long ptr,
+ size_t size, int min_count, bool is_phys)
+{
+
+ struct kmemleak_object *parent;
+ struct rb_node **link, *rb_parent;
+ unsigned long untagged_ptr;
+ unsigned long untagged_objp;
+
+ object->flags = OBJECT_ALLOCATED | (is_phys ? OBJECT_PHYS : 0);
+ object->pointer = ptr;
+ object->size = kfence_ksize((void *)ptr) ?: size;
+ object->min_count = min_count;
+ object->jiffies = jiffies;
+
untagged_ptr = (unsigned long)kasan_reset_tag((void *)ptr);
/*
* Only update min_addr and max_addr with object
--
2.25.1