binder: fix memory leak in binder_init()

In binder_init(), the destruction of binder_alloc_shrinker_init() is not
performed in the wrong path, which will cause memory leaks. So this commit
introduces binder_alloc_shrinker_exit() and calls it in the wrong path to
fix that.

Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Acked-by: Carlos Llamas <cmllamas@google.com>
Fixes: f2517eb ("android: binder: Add global lru shrinker to binder")
Cc: stable <stable@kernel.org>
Link: https://lore.kernel.org/r/20230625154937.64316-1-qi.zheng@linux.dev
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: Qi Zheng

drivers/android/binder.c

@@ -6617,6 +6617,7 @@ static int __init binder_init(void)
 
 err_alloc_device_names_failed:
 	debugfs_remove_recursive(binder_debugfs_dir_entry_root);
+	binder_alloc_shrinker_exit();
 
 	return ret;
 }

drivers/android/binder_alloc.c

@@ -1087,6 +1087,12 @@ int binder_alloc_shrinker_init(void)
 	return ret;
 }
 
+void binder_alloc_shrinker_exit(void)
+{
+	unregister_shrinker(&binder_shrinker);
+	list_lru_destroy(&binder_alloc_lru);
+}
+
 /**
  * check_buffer() - verify that buffer/offset is safe to access
  * @alloc: binder_alloc for this proc

drivers/android/binder_alloc.h

@@ -129,6 +129,7 @@ extern struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc,
 						  int pid);
 extern void binder_alloc_init(struct binder_alloc *alloc);
 extern int binder_alloc_shrinker_init(void);
+extern void binder_alloc_shrinker_exit(void);
 extern void binder_alloc_vma_close(struct binder_alloc *alloc);
 extern struct binder_buffer *
 binder_alloc_prepare_to_free(struct binder_alloc *alloc,