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

Ben Hutchings
2018-09-11T20:02:51Z

On Thu, 2018-08-23 at 09:53 +0200, Greg Kroah-Hartman wrote:
> 4.4-stable review patch.  If anyone has any objections, please let me know.
>
> ------------------
>
> From: Stefan Schmidt <stefan@datenfreihafen.org>
>
> [ 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@datenfreihafen.org>
> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> ---
>  drivers/net/ieee802154/at86rf230.c |    2 +-
>  1 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,
>  static int
>  at86rf230_ed(struct ieee802154_hw *hw, u8 *level)
>  {
> - BUG_ON(!level);
> + WARN_ON(!level);
>   *level = 0xbe;
>   return 0;
>  }

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