kasan: add tests for call_rcu stack recording

Test call_rcu() call stack recording and verify whether it correctly is
printed in KASAN report.
Signed-off-by: Walter Wu <walter-zh.wu@mediatek.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: "Paul E . McKenney" <paulmck@kernel.org>
Link: http://lkml.kernel.org/r/20200601051045.1294-1-walter-zh.wu@mediatek.comSigned-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/test_kasan.c

@@ -801,6 +801,35 @@ static noinline void __init vmalloc_oob(void)
 static void __init vmalloc_oob(void) {}
 #endif
 
+static struct kasan_rcu_info {
+	int i;
+	struct rcu_head rcu;
+} *global_rcu_ptr;
+
+static noinline void __init kasan_rcu_reclaim(struct rcu_head *rp)
+{
+	struct kasan_rcu_info *fp = container_of(rp,
+						struct kasan_rcu_info, rcu);
+
+	kfree(fp);
+	fp->i = 1;
+}
+
+static noinline void __init kasan_rcu_uaf(void)
+{
+	struct kasan_rcu_info *ptr;
+
+	pr_info("use-after-free in kasan_rcu_reclaim\n");
+	ptr = kmalloc(sizeof(struct kasan_rcu_info), GFP_KERNEL);
+	if (!ptr) {
+		pr_err("Allocation failed\n");
+		return;
+	}
+
+	global_rcu_ptr = rcu_dereference_protected(ptr, NULL);
+	call_rcu(&global_rcu_ptr->rcu, kasan_rcu_reclaim);
+}
+
 static int __init kmalloc_tests_init(void)
 {
 	/*
@@ -848,6 +877,7 @@ static int __init kmalloc_tests_init(void)
 	kasan_bitops();
 	kmalloc_double_kzfree();
 	vmalloc_oob();
+	kasan_rcu_uaf();
 
 	kasan_restore_multi_shot(multishot);