lib/test_meminit: optimize do_kmem_cache_rcu_persistent() test

To make the test more robust, there are the following changes:
1. add a check for the return value of kmem_cache_alloc().
2. properly release the object `buf` on several error paths.
3. release the objects of `used_objects` if we never hit `saved_ptr`.
4. destroy the created cache by default.

Link: https://lkml.kernel.org/r/tencent_7CB95F1C3914BCE1CA4A61FF7C20E7CCB108@qq.com
Signed-off-by: Xiaoke Wang <xkernel.wang@foxmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Marco Elver <elver@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Xiaoke Wang <xkernel.wang@foxmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 10 insertions, 2 deletions

diff --git a/lib/test_meminit.c b/lib/test_meminit.c
index 3ca717f11397..c95db11a6906 100644
--- a/lib/test_meminit.c
+++ b/lib/test_meminit.c
@@ -279,13 +279,18 @@ static int __init do_kmem_cache_rcu_persistent(int size, int *total_failures)
 	c = kmem_cache_create("test_cache", size, size, SLAB_TYPESAFE_BY_RCU,
 			      NULL);
 	buf = kmem_cache_alloc(c, GFP_KERNEL);
+	if (!buf)
+		goto out;
 	saved_ptr = buf;
 	fill_with_garbage(buf, size);
 	buf_contents = kmalloc(size, GFP_KERNEL);
-	if (!buf_contents)
+	if (!buf_contents) {
+		kmem_cache_free(c, buf);
 		goto out;
+	}
 	used_objects = kmalloc_array(maxiter, sizeof(void *), GFP_KERNEL);
 	if (!used_objects) {
+		kmem_cache_free(c, buf);
 		kfree(buf_contents);
 		goto out;
 	}
@@ -306,11 +311,14 @@ static int __init do_kmem_cache_rcu_persistent(int size, int *total_failures)
 		}
 	}
 
+	for (iter = 0; iter < maxiter; iter++)
+		kmem_cache_free(c, used_objects[iter]);
+
 free_out:
-	kmem_cache_destroy(c);
 	kfree(buf_contents);
 	kfree(used_objects);
 out:
+	kmem_cache_destroy(c);
 	*total_failures += fail;
 	return 1;
 }