linux-kernel - [RFC/PATCH v2 09/10] kmemleak: disable kasan instrumentation for kmemleak

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Message-id: <1410359487-31938-10-git-send-email-a.ryabinin@samsung.com>
Date:	Wed, 10 Sep 2014 18:31:26 +0400
From:	Andrey Ryabinin <a.ryabinin@...sung.com>
To:	linux-kernel@...r.kernel.org
Cc:	Andrey Ryabinin <a.ryabinin@...sung.com>,
	Dmitry Vyukov <dvyukov@...gle.com>,
	Konstantin Serebryany <kcc@...gle.com>,
	Dmitry Chernenkov <dmitryc@...gle.com>,
	Andrey Konovalov <adech.fo@...il.com>,
	Yuri Gribov <tetra2005@...il.com>,
	Konstantin Khlebnikov <koct9i@...il.com>,
	Sasha Levin <sasha.levin@...cle.com>,
	Christoph Lameter <cl@...ux.com>,
	Joonsoo Kim <iamjoonsoo.kim@....com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Dave Hansen <dave.hansen@...el.com>,
	Andi Kleen <andi@...stfloor.org>,
	Vegard Nossum <vegard.nossum@...il.com>,
	"H. Peter Anvin" <hpa@...or.com>, x86@...nel.org,
	linux-mm@...ck.org, Catalin Marinas <catalin.marinas@....com>
Subject: [RFC/PATCH v2 09/10] kmemleak: disable kasan instrumentation for
 kmemleak

kmemleak scans all memory while searching for pointers to
objects. So function scan_block could access
kasan's shadow memory region while searching for pointer.

Also kmalloc internally round up allocation size, and kmemleak
uses rounded up size as size of object. This makes kasan
to complain while calculation of object's checksum. The
simplest solution here is to disable kasan.

Signed-off-by: Andrey Ryabinin <a.ryabinin@...sung.com>
---
 mm/kmemleak.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index 3cda50c..9bda1b3 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -98,6 +98,7 @@
 #include <asm/processor.h>
 #include <linux/atomic.h>
 
+#include <linux/kasan.h>
 #include <linux/kmemcheck.h>
 #include <linux/kmemleak.h>
 #include <linux/memory_hotplug.h>
@@ -1113,7 +1114,10 @@ static bool update_checksum(struct kmemleak_object *object)
 	if (!kmemcheck_is_obj_initialized(object->pointer, object->size))
 		return false;
 
+	kasan_disable_local();
 	object->checksum = crc32(0, (void *)object->pointer, object->size);
+	kasan_enable_local();
+
 	return object->checksum != old_csum;
 }
 
@@ -1164,7 +1168,9 @@ static void scan_block(void *_start, void *_end,
 						  BYTES_PER_POINTER))
 			continue;
 
+		kasan_disable_local();
 		pointer = *ptr;
+		kasan_enable_local();
 
 		object = find_and_get_object(pointer, 1);
 		if (!object)
-- 
1.8.5.5

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