[PATCH v3 1/3] mm: kmemleak: add OBJECT_PHYS flag for objects allocated with physical address

Patrick Wang
2022-06-09T12:51:28Z

Add OBJECT_PHYS flag for object. This flag is used
to identify the objects allocated with physical
address.The create_object_phys() function is added as
well to set that flag. And remove the min_count
argument to kmemleak_alloc_phys() function, assume
it's 0.

Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Patrick Wang <patrick.wang.shcn@gmail.com>
---
drivers/of/fdt.c | 2 +-
include/linux/kmemleak.h | 4 +--
mm/kmemleak.c | 44 ++++++++++++++++++-------
mm/memblock.c | 14 ++++----
tools/testing/memblock/linux/kmemleak.h | 2 +-
5 files changed, 43 insertions(+), 23 deletions(-)

diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index a8f5b6532165..2c677e84c3f5 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -529,7 +529,7 @@ static int __init __reserved_mem_reserve_reg(unsigned long node,
pr_debug("Reserved memory: reserved region for node '%s': base %pa, size %lu MiB\n",
uname, &base, (unsigned long)(size / SZ_1M));
if (!nomap)
- kmemleak_alloc_phys(base, size, 0, 0);
+ kmemleak_alloc_phys(base, size, 0);
}
else
pr_info("Reserved memory: failed to reserve memory for node '%s': base %pa, size %lu MiB\n",
diff --git a/include/linux/kmemleak.h b/include/linux/kmemleak.h
index 34684b2026ab..df245d875b1e 100644
--- a/include/linux/kmemleak.h
+++ b/include/linux/kmemleak.h
@@ -29,7 +29,7 @@ extern void kmemleak_not_leak(const void *ptr) __ref;
extern void kmemleak_ignore(const void *ptr) __ref;
extern void kmemleak_scan_area(const void *ptr, size_t size, gfp_t gfp) __ref;
extern void kmemleak_no_scan(const void *ptr) __ref;
-extern void kmemleak_alloc_phys(phys_addr_t phys, size_t size, int min_count,
+extern void kmemleak_alloc_phys(phys_addr_t phys, size_t size,
gfp_t gfp) __ref;
extern void kmemleak_free_part_phys(phys_addr_t phys, size_t size) __ref;
extern void kmemleak_not_leak_phys(phys_addr_t phys) __ref;
@@ -107,7 +107,7 @@ static inline void kmemleak_no_scan(const void *ptr)
{
}
static inline void kmemleak_alloc_phys(phys_addr_t phys, size_t size,
- int min_count, gfp_t gfp)
+ gfp_t gfp)
{
}
static inline void kmemleak_free_part_phys(phys_addr_t phys, size_t size)
diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index a182f5ddaf68..85ed719e750d 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -172,6 +172,8 @@ struct kmemleak_object {
#define OBJECT_NO_SCAN (1 << 2)
/* flag set to fully scan the object when scan_area allocation failed */
#define OBJECT_FULL_SCAN (1 << 3)
+/* flag set for object allocated with physical address */
+#define OBJECT_PHYS (1 << 4)

#define HEX_PREFIX " "
/* number of bytes to print per line; must be 16 or 32 */
@@ -574,8 +576,9 @@ static int __save_stack_trace(unsigned long *trace)
* Create the metadata (struct kmemleak_object) corresponding to an allocated
* memory block and add it to the object_list and object_tree_root.
*/
-static struct kmemleak_object *create_object(unsigned long ptr, size_t size,
- int min_count, gfp_t gfp)
+static struct kmemleak_object *__create_object(unsigned long ptr, size_t size,
+ int min_count, gfp_t gfp,
+ bool is_phys)
{
unsigned long flags;
struct kmemleak_object *object, *parent;
@@ -595,7 +598,7 @@ static struct kmemleak_object *create_object(unsigned long ptr, size_t size,
INIT_HLIST_HEAD(&object->area_list);
raw_spin_lock_init(&object->lock);
atomic_set(&object->use_count, 1);
- object->flags = OBJECT_ALLOCATED;
+ object->flags = OBJECT_ALLOCATED | (is_phys ? OBJECT_PHYS : 0);
object->pointer = ptr;
object->size = kfence_ksize((void *)ptr) ?: size;
object->excess_ref = 0;
@@ -662,6 +665,20 @@ static struct kmemleak_object *create_object(unsigned long ptr, size_t size,
return object;
}

+/* Create kmemleak object which allocated with virtual address. */
+static struct kmemleak_object *create_object(unsigned long ptr, size_t size,
+ int min_count, gfp_t gfp)
+{
+ return __create_object(ptr, size, min_count, gfp, false);
+}
+
+/* Create kmemleak object which allocated with physical address. */
+static struct kmemleak_object *create_object_phys(unsigned long ptr, size_t size,
+ int min_count, gfp_t gfp)
+{
+ return __create_object(ptr, size, min_count, gfp, true);
+}
+
/*
* Mark the object as not allocated and schedule RCU freeing via put_object().
*/
@@ -728,11 +745,11 @@ static void delete_object_part(unsigned long ptr, size_t size)
start = object->pointer;
end = object->pointer + object->size;
if (ptr > start)
- create_object(start, ptr - start, object->min_count,
- GFP_KERNEL);
+ __create_object(start, ptr - start, object->min_count,
+ GFP_KERNEL, object->flags & OBJECT_PHYS);
if (ptr + size < end)
- create_object(ptr + size, end - ptr - size, object->min_count,
- GFP_KERNEL);
+ __create_object(ptr + size, end - ptr - size, object->min_count,
+ GFP_KERNEL, object->flags & OBJECT_PHYS);

__delete_object(object);
}
@@ -1125,15 +1142,18 @@ EXPORT_SYMBOL(kmemleak_no_scan);
* address argument
* @phys: physical address of the object
* @size: size of the object
- * @min_count: minimum number of references to this object.
- * See kmemleak_alloc()
* @gfp: kmalloc() flags used for kmemleak internal memory allocations
*/
-void __ref kmemleak_alloc_phys(phys_addr_t phys, size_t size, int min_count,
- gfp_t gfp)
+void __ref kmemleak_alloc_phys(phys_addr_t phys, size_t size, gfp_t gfp)
{
+ pr_debug("%s(0x%pa, %zu)\n", __func__, &phys, size);
+
if (PHYS_PFN(phys) >= min_low_pfn && PHYS_PFN(phys) < max_low_pfn)
- kmemleak_alloc(__va(phys), size, min_count, gfp);
+ /*
+ * Create object with OBJECT_PHYS flag and
+ * assume min_count 0.
+ */
+ create_object_phys((unsigned long)__va(phys), size, 0, gfp);
}
EXPORT_SYMBOL(kmemleak_alloc_phys);

diff --git a/mm/memblock.c b/mm/memblock.c
index e4f03a6e8e56..749abd2685c4 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -1345,8 +1345,8 @@ __next_mem_pfn_range_in_zone(u64 *idx, struct zone *zone,
* from the regions with mirroring enabled and then retried from any
* memory region.
*
- * In addition, function sets the min_count to 0 using kmemleak_alloc_phys for
- * allocated boot memory block, so that it is never reported as leaks.
+ * In addition, function using kmemleak_alloc_phys for allocated boot
+ * memory block, it is never reported as leaks.
*
* Return:
* Physical address of allocated memory block on success, %0 on failure.
@@ -1398,12 +1398,12 @@ phys_addr_t __init memblock_alloc_range_nid(phys_addr_t size,
*/
if (end != MEMBLOCK_ALLOC_NOLEAKTRACE)
/*
- * The min_count is set to 0 so that memblock allocated
- * blocks are never reported as leaks. This is because many
- * of these blocks are only referred via the physical
- * address which is not looked up by kmemleak.
+ * Memblock allocated blocks are never reported as
+ * leaks. This is because many of these blocks are
+ * only referred via the physical address which is
+ * not looked up by kmemleak.
*/
- kmemleak_alloc_phys(found, size, 0, 0);
+ kmemleak_alloc_phys(found, size, 0);

return found;
}
diff --git a/tools/testing/memblock/linux/kmemleak.h b/tools/testing/memblock/linux/kmemleak.h
index 462f8c5e8aa0..5fed13bb9ec4 100644
--- a/tools/testing/memblock/linux/kmemleak.h
+++ b/tools/testing/memblock/linux/kmemleak.h
@@ -7,7 +7,7 @@ static inline void kmemleak_free_part_phys(phys_addr_t phys, size_t size)
}

static inline void kmemleak_alloc_phys(phys_addr_t phys, size_t size,
- int min_count, gfp_t gfp)
+ gfp_t gfp)
{
}

--
2.25.1