Re: [PATCH 4.4 47/79] ieee802154: at86rf230: switch from BUG_ON() to WARN_ON() on problem

[Ben Hutchings]

On Thu, 2018-08-23 at 09:53 +0200, Greg Kroah-Hartman wrote:
> 4.4-stable review patch.ÂÂIf anyone has any objections, please let me know.
> 
> ------------------
> 
> From: Stefan Schmidt <stefan@xxxxxxxxxxxxxxxxxx>
> 
> [ Upstream commit 20f330452ad8814f2289a589baf65e21270879a7 ]
> 
> The check is valid but it does not warrant to crash the kernel. A
> WARN_ON() is good enough here.
> Found by checkpatch.

If the BUG/WARN fires, the very next statement is going to cause an
oops.  So this doesn't fix anything.

Either it's OK for a null pointer to be a fatal error, in which case
the WARN can be removed, or that shouldn't be a fatal error, in which
case the following assignment needs to be conditional.

Ben.

> Signed-off-by: Stefan Schmidt <stefan@xxxxxxxxxxxxxxxxxx>
> Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> ---
> Âdrivers/net/ieee802154/at86rf230.c |ÂÂÂÂ2 +-
> Â1 file changed, 1 insertion(+), 1 deletion(-)
> 
> --- a/drivers/net/ieee802154/at86rf230.c
> +++ b/drivers/net/ieee802154/at86rf230.c
> @@ -932,7 +932,7 @@ at86rf230_xmit(struct ieee802154_hw *hw,
> Âstatic int
> Âat86rf230_ed(struct ieee802154_hw *hw, u8 *level)
> Â{
> -	BUG_ON(!level);
> +	WARN_ON(!level);
> Â	*level = 0xbe;
> Â	return 0;
> Â}

-- 
Ben Hutchings, Software Developer                Â        Codethink Ltd
https://www.codethink.co.uk/                 Dale House, 35 Dale Street
                                     Manchester, M1 2HF, United Kingdom