linux-kernel - Re: [PATCH] binder: fix memory leak in binder

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Date:   Sun, 25 Jun 2023 16:16:28 +0000
From:   Carlos Llamas <cmllamas@...gle.com>
To:     Qi Zheng <qi.zheng@...ux.dev>
Cc:     gregkh@...uxfoundation.org, arve@...roid.com, tkjos@...roid.com,
        maco@...roid.com, joel@...lfernandes.org, brauner@...nel.org,
        surenb@...gle.com, linux-kernel@...r.kernel.org,
        Qi Zheng <zhengqi.arch@...edance.com>
Subject: Re: [PATCH] binder: fix memory leak in binder_init()

On Sun, Jun 25, 2023 at 03:49:37PM +0000, Qi Zheng wrote:
> From: Qi Zheng <zhengqi.arch@...edance.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@...edance.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
> 

Thanks for the fix Qi Zheng.

Acked-by: Carlos Llamas <cmllamas@...gle.com>