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From:   Qi Zheng <qi.zheng@linux.dev>
To:     gregkh@linuxfoundation.org, arve@android.com, tkjos@android.com,
        maco@android.com, joel@joelfernandes.org, brauner@kernel.org,
        cmllamas@google.com, surenb@google.com
Cc:     linux-kernel@vger.kernel.org, Qi Zheng <zhengqi.arch@bytedance.com>
Subject: [PATCH] binder: fix memory leak in binder_init()
Date:   Sun, 25 Jun 2023 15:49:37 +0000
Message-Id: <20230625154937.64316-1-qi.zheng@linux.dev>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

From: Qi Zheng <zhengqi.arch@bytedance.com>

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>
---
 drivers/android/binder.c       | 1 +
 drivers/android/binder_alloc.c | 6 ++++++
 drivers/android/binder_alloc.h | 1 +
 3 files changed, 8 insertions(+)

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 486c8271cab7..d720f93d8b19 100644
--- a/drivers/android/binder.c
+++ b/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;
 }
diff --git a/drivers/android/binder_alloc.c b/drivers/android/binder_alloc.c
index 662a2a2e2e84..e3db8297095a 100644
--- a/drivers/android/binder_alloc.c
+++ b/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
diff --git a/drivers/android/binder_alloc.h b/drivers/android/binder_alloc.h
index 138d1d5af9ce..dc1e2b01dd64 100644
--- a/drivers/android/binder_alloc.h
+++ b/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,
-- 
2.30.2