linux-kernel - [PATCH v2 4/4] mm: kmemleak: kmemleak_*_phys() set address type and check PA when scan

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Date:   Fri,  3 Jun 2022 11:54:15 +0800
From:   Patrick Wang <patrick.wang.shcn@...il.com>
To:     catalin.marinas@....com, akpm@...ux-foundation.org
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        yee.lee@...iatek.com, patrick.wang.shcn@...il.com
Subject: [PATCH v2 4/4] mm: kmemleak: kmemleak_*_phys() set address type and check PA when scan

The kmemleak_*_phys() functions call next level interface
by setting address type to physical. And the physical address
of objects will be checked for its boundary when scan instead
of in kmemleak_*_phys().

Suggested-by: Catalin Marinas <catalin.marinas@....com>
Signed-off-by: Patrick Wang <patrick.wang.shcn@...il.com>
---
 mm/kmemleak.c | 37 +++++++++++++++++++++++++++++--------
 1 file changed, 29 insertions(+), 8 deletions(-)

diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index 246a70b7218f..62d1ad8f8a44 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -1156,8 +1156,12 @@ EXPORT_SYMBOL(kmemleak_no_scan);
 void __ref kmemleak_alloc_phys(phys_addr_t phys, size_t size, int min_count,
 			       gfp_t gfp)
 {
-	if (PHYS_PFN(phys) >= min_low_pfn && PHYS_PFN(phys) < max_low_pfn)
-		kmemleak_alloc(__va(phys), size, min_count, gfp);
+	pr_debug("%s(0x%pa, %zu, %d)\n", __func__, &phys, size, min_count);
+
+	if (kmemleak_enabled && !min_count)
+		/* create object with OBJECT_PHYS flag */
+		create_object((unsigned long)phys, size, min_count,
+			      gfp, true);
 }
 EXPORT_SYMBOL(kmemleak_alloc_phys);
 
@@ -1170,8 +1174,10 @@ EXPORT_SYMBOL(kmemleak_alloc_phys);
  */
 void __ref kmemleak_free_part_phys(phys_addr_t phys, size_t size)
 {
-	if (PHYS_PFN(phys) >= min_low_pfn && PHYS_PFN(phys) < max_low_pfn)
-		kmemleak_free_part(__va(phys), size);
+	pr_debug("%s(0x%pa)\n", __func__, &phys);
+
+	if (kmemleak_enabled)
+		delete_object_part((unsigned long)phys, size, true);
 }
 EXPORT_SYMBOL(kmemleak_free_part_phys);
 
@@ -1182,8 +1188,10 @@ EXPORT_SYMBOL(kmemleak_free_part_phys);
  */
 void __ref kmemleak_not_leak_phys(phys_addr_t phys)
 {
-	if (PHYS_PFN(phys) >= min_low_pfn && PHYS_PFN(phys) < max_low_pfn)
-		kmemleak_not_leak(__va(phys));
+	pr_debug("%s(0x%pa)\n", __func__, &phys);
+
+	if (kmemleak_enabled)
+		make_gray_object((unsigned long)phys, true);
 }
 EXPORT_SYMBOL(kmemleak_not_leak_phys);
 
@@ -1194,8 +1202,10 @@ EXPORT_SYMBOL(kmemleak_not_leak_phys);
  */
 void __ref kmemleak_ignore_phys(phys_addr_t phys)
 {
-	if (PHYS_PFN(phys) >= min_low_pfn && PHYS_PFN(phys) < max_low_pfn)
-		kmemleak_ignore(__va(phys));
+	pr_debug("%s(0x%pa)\n", __func__, &phys);
+
+	if (kmemleak_enabled)
+		make_black_object((unsigned long)phys, true);
 }
 EXPORT_SYMBOL(kmemleak_ignore_phys);
 
@@ -1468,6 +1478,17 @@ static void kmemleak_scan(void)
 			dump_object_info(object);
 		}
 #endif
+
+		/* ignore objects outside lowmem (paint them black) */
+		if ((object->flags & OBJECT_PHYS) &&
+		   !(object->flags & OBJECT_NO_SCAN)) {
+			unsigned long phys = object->pointer;
+
+			if (PHYS_PFN(phys) < min_low_pfn ||
+			    PHYS_PFN(phys + object->size) >= max_low_pfn)
+				__paint_it(object, KMEMLEAK_BLACK);
+		}
+
 		/* reset the reference count (whiten the object) */
 		object->count = 0;
 		if (color_gray(object) && get_object(object))
-- 
2.25.1