[PATCH RFC 6/6] kunit, slub: add test_kfree_rcu()

[Vlastimil Babka]

Add a test that will create cache, allocate one object, kfree_rcu() it
and attempt to destroy it. If the asynchronous cache freeing works
correctly, there should be no warnings in dmesg.

Since the warnings in the failure case are produced by a work callback,
I don't know if it's possible to capture it in the kunit test result
properly.

Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx>
---
 lib/slub_kunit.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/lib/slub_kunit.c b/lib/slub_kunit.c
index e6667a28c014..e3e4d0ca40b7 100644
--- a/lib/slub_kunit.c
+++ b/lib/slub_kunit.c
@@ -5,6 +5,7 @@
 #include <linux/slab.h>
 #include <linux/module.h>
 #include <linux/kernel.h>
+#include <linux/rcupdate.h>
 #include "../mm/slab.h"
 
 static struct kunit_resource resource;
@@ -157,6 +158,26 @@ static void test_kmalloc_redzone_access(struct kunit *test)
 	kmem_cache_destroy(s);
 }
 
+struct test_kfree_rcu_struct {
+	struct rcu_head rcu;
+};
+
+static void test_kfree_rcu(struct kunit *test)
+{
+	struct kmem_cache *s = test_kmem_cache_create("TestSlub_kfree_rcu",
+				sizeof(struct test_kfree_rcu_struct),
+				SLAB_NO_MERGE);
+	struct test_kfree_rcu_struct *p = kmem_cache_alloc(s, GFP_KERNEL);
+
+	kasan_disable_current();
+
+	KUNIT_EXPECT_EQ(test, 0, slab_errors);
+
+	kasan_enable_current();
+	kfree_rcu(p, rcu);
+	kmem_cache_destroy(s);
+}
+
 static int test_init(struct kunit *test)
 {
 	slab_errors = 0;
@@ -177,6 +198,7 @@ static struct kunit_case test_cases[] = {
 
 	KUNIT_CASE(test_clobber_redzone_free),
 	KUNIT_CASE(test_kmalloc_redzone_access),
+	KUNIT_CASE(test_kfree_rcu),
 	{}
 };
 

-- 
2.45.2