lib/test_kasan: Add test for double-kzfree detection

Add a simple test that checks if double-kzfree is being detected
correctly.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Marco Elver <[email protected]>
Reviewed-by: Andrey Ryabinin <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: Alexander Potapenko <[email protected]>
Cc: Andrey Konovalov <[email protected]>
Cc: Christoph Lameter <[email protected]>
Cc: Pekka Enberg <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Joonsoo Kim <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Kees Cook <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

1 files changed, 17 insertions, 0 deletions

diff --git a/lib/test_kasan.c b/lib/test_kasan.c
index d85f25c65b0a..b63b367a94e8 100644
--- a/lib/test_kasan.c
+++ b/lib/test_kasan.c
@@ -693,6 +693,22 @@ static noinline void __init kasan_bitops(void)
 	kfree(bits);
 }
 
+static noinline void __init kmalloc_double_kzfree(void)
+{
+	char *ptr;
+	size_t size = 16;
+
+	pr_info("double-free (kzfree)\n");
+	ptr = kmalloc(size, GFP_KERNEL);
+	if (!ptr) {
+		pr_err("Allocation failed\n");
+		return;
+	}
+
+	kzfree(ptr);
+	kzfree(ptr);
+}
+
 static int __init kmalloc_tests_init(void)
 {
 	/*
@@ -735,6 +751,7 @@ static int __init kmalloc_tests_init(void)
 	kasan_memcmp();
 	kasan_strings();
 	kasan_bitops();
+	kmalloc_double_kzfree();
 
 	kasan_restore_multi_shot(multishot);