mm: kmemleak: check physical address when scan

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2151065
Conflicts: A minor context diff due to the presence of a later upstream
	   commit 6edda04 ("mm/kmemleak: prevent soft lockup in
	   first object iteration loop of kmemleak_scan()").

commit 84c3262
Author: Patrick Wang <patrick.wang.shcn@gmail.com>
Date:   Sat, 11 Jun 2022 11:55:51 +0800

    mm: kmemleak: check physical address when scan

    Check the physical address of objects for its boundary when scan instead
    of in kmemleak_*_phys().

    Link: https://lkml.kernel.org/r/20220611035551.1823303-5-patrick.wang.shcn@gmail.com
    Fixes: 23c2d49 ("mm: kmemleak: take a full lowmem check in kmemleak_*_phys()")
    Signed-off-by: Patrick Wang <patrick.wang.shcn@gmail.com>
    Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
    Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
    Cc: Yee Lee <yee.lee@mediatek.com>
    Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Signed-off-by: Waiman Long <longman@redhat.com>

Author: Waiman-Long

mm/kmemleak.c

@@ -1184,7 +1184,7 @@ 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)
+	if (kmemleak_enabled)
 		/*
 		 * Create object with OBJECT_PHYS flag and
 		 * assume min_count 0.
@@ -1204,7 +1204,7 @@ void __ref kmemleak_free_part_phys(phys_addr_t phys, size_t size)
 {
 	pr_debug("%s(0x%pa)\n", __func__, &phys);
 
-	if (PHYS_PFN(phys) >= min_low_pfn && PHYS_PFN(phys) < max_low_pfn)
+	if (kmemleak_enabled)
 		delete_object_part((unsigned long)phys, size, true);
 }
 EXPORT_SYMBOL(kmemleak_free_part_phys);
@@ -1218,7 +1218,7 @@ void __ref kmemleak_ignore_phys(phys_addr_t phys)
 {
 	pr_debug("%s(0x%pa)\n", __func__, &phys);
 
-	if (PHYS_PFN(phys) >= min_low_pfn && PHYS_PFN(phys) < max_low_pfn)
+	if (kmemleak_enabled)
 		make_black_object((unsigned long)phys, true);
 }
 EXPORT_SYMBOL(kmemleak_ignore_phys);
@@ -1516,6 +1516,17 @@ 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)) {