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Date:   Mon, 12 Oct 2020 10:18:13 -0400
From:   "J. Bruce Fields" <bfields@fieldses.org>
To:     Artur Molchanov <arturmolchanov@gmail.com>
Cc:     chuck.lever@oracle.com, linux-nfs@vger.kernel.org
Subject: Re: [PATCH v2] net/sunrpc: Fix return value for sysctl
 sunrpc.transports
Message-ID: <20201012141813.GB26571@fieldses.org>
References: <20C3D746-91F5-45E1-B105-0A1B1ABAA9BB@gmail.com>
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On Mon, Oct 12, 2020 at 01:00:45AM +0300, Artur Molchanov wrote:
> Fix returning value for sysctl sunrpc.transports.
> Return error code from sysctl proc_handler function proc_do_xprt instead of number of the written bytes.
> Otherwise sysctl returns random garbage for this key.
> 
> Since v1:
> - Handle negative returned value from memory_read_from_buffer as an error

Thanks, applying for 5.10.--b.

> 
> 
> Signed-off-by: Artur Molchanov <arturmolchanov@gmail.com>
> Cc: stable@vger.kernel.org
> ---
>  net/sunrpc/sysctl.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/net/sunrpc/sysctl.c b/net/sunrpc/sysctl.c
> index 999eee1ed61c..e81a28f30f1d 100644
> --- a/net/sunrpc/sysctl.c
> +++ b/net/sunrpc/sysctl.c
> @@ -70,7 +70,13 @@ static int proc_do_xprt(struct ctl_table *table, int write,
>  		return 0;
>  	}
>  	len = svc_print_xprts(tmpbuf, sizeof(tmpbuf));
> -	return memory_read_from_buffer(buffer, *lenp, ppos, tmpbuf, len);
> +	*lenp = memory_read_from_buffer(buffer, *lenp, ppos, tmpbuf, len);
> +
> +	if (*lenp < 0) {
> +		*lenp = 0;
> +		return -EINVAL;
> +	}
> +	return 0;
>  }
>  
>  static int
> -- 
> 2.20.1