Re: [PATCH] staging: android: ashmem: add size field in procfs fdinfo

From: Greg KH <gregkh@linuxfoundation.org>
To: liuhailong <liuhailong@oppo.com>
Cc: arve@android.com, tkjos@android.com, maco@android.com,
	joel@joelfernandes.org, christian@brauner.io, hridya@google.com,
	surenb@google.com, linux-kernel@vger.kernel.org,
	linux-staging@lists.linux.dev
Subject: Re: [PATCH] staging: android: ashmem: add size field in procfs fdinfo
Date: Fri, 18 Jun 2021 12:23:20 +0200	[thread overview]
Message-ID: <YMx0GIRQmpRC7pdQ@kroah.com> (raw)
In-Reply-To: <20210618095035.32410-1-liuhailong@oppo.com>

On Fri, Jun 18, 2021 at 05:50:35PM +0800, liuhailong wrote:
> add this information to help user to find ashmem problem.
> 
> ashmem leak scenario:
> -000|fd = ashmem_create_region
> -001|mmap and pagefault
> -002|munmap
> -003|forget close(fd) <---- which lead to ashmem leak
> 
> Signed-off-by: liuhailong <liuhailong@oppo.com>
> ---
>  drivers/staging/android/ashmem.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/staging/android/ashmem.c b/drivers/staging/android/ashmem.c
> index d66a64e42273..ee2fd75111d8 100644
> --- a/drivers/staging/android/ashmem.c
> +++ b/drivers/staging/android/ashmem.c
> @@ -894,6 +894,8 @@ static void ashmem_show_fdinfo(struct seq_file *m, struct file *file)
>  		seq_printf(m, "name:\t%s\n",
>  			   asma->name + ASHMEM_NAME_PREFIX_LEN);
>  
> +	seq_printf(m, "size:\t%zu\n", asma->size);
> +
>  	mutex_unlock(&ashmem_mutex);
>  }
>  #endif
> -- 
> 2.30.2
> 
> 

As you are changing a user-facing proc file, what tools will break now
that you have added a new line?

What tools do you use to look at this file and what has been modified to
handle the change?

thanks,

greg k-h