[PATCH v5 3/4] kasan: add tests for call_rcu stack recording

[Walter Wu]

Test call_rcu() call stack recording and verify whether it correctly
is printed in KASAN report.

Signed-off-by: Walter Wu <walter-zh.wu@xxxxxxxxxxxx>
Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Matthias Brugger <matthias.bgg@xxxxxxxxx>
---
 lib/test_kasan.c | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/lib/test_kasan.c b/lib/test_kasan.c
index e3087d90e00d..6e5fb05d42d8 100644
--- a/lib/test_kasan.c
+++ b/lib/test_kasan.c
@@ -792,6 +792,35 @@ 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_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_ptr = rcu_dereference_protected(ptr, NULL);
+	call_rcu(&global_ptr->rcu, kasan_rcu_reclaim);
+}
+
 static int __init kmalloc_tests_init(void)
 {
 	/*
@@ -839,6 +868,7 @@ static int __init kmalloc_tests_init(void)
 	kasan_bitops();
 	kmalloc_double_kzfree();
 	vmalloc_oob();
+	kasan_rcu_uaf();
 
 	kasan_restore_multi_shot(multishot);
 
-- 
2.18.0