kasan: test fix: warn if the UAF could not be detected in kmalloc_uaf2

Signed-off-by: Alexander Potapenko <[email protected]>
Acked-by: Andrey Ryabinin <[email protected]>
Cc: Christoph Lameter <[email protected]>
Cc: Pekka Enberg <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Joonsoo Kim <[email protected]>
Cc: Andrey Konovalov <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Konstantin Serebryany <[email protected]>
Cc: Dmitry Chernenkov <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

Author: ramosian-glider

lib/test_kasan.c

@@ -294,6 +294,8 @@ static noinline void __init kmalloc_uaf2(void)
 	}
 
 	ptr1[40] = 'x';
+	if (ptr1 == ptr2)
+		pr_err("Could not detect use-after-free: ptr1 == ptr2\n");
 	kfree(ptr2);
 }