Re: [PATCH] net: Fix oops in dev_ifsioc()

[Wang Chen <wangchen@cn.fujitsu.com>]

Jarek Poplawski said the following on 2008-12-19 15:04:
> A command like this: "brctl addif br1 eth1" issued as a user gave me
> an oops when bridge module wasn't loaded. It's caused by using a dev
> pointer before checking for NULL.
> 
> Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
> ---
> 
>  net/core/dev.c |    4 +++-
>  1 files changed, 3 insertions(+), 1 deletions(-)
> 
> diff --git a/net/core/dev.c b/net/core/dev.c
> index 048cf11..daca72e 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -3745,11 +3745,13 @@ static int dev_ifsioc(struct net *net, struct ifreq *ifr, unsigned int cmd)
>  {
>  	int err;
>  	struct net_device *dev = __dev_get_by_name(net, ifr->ifr_name);
> -	const struct net_device_ops *ops = dev->netdev_ops;
> +	const struct net_device_ops *ops;
>  
>  	if (!dev)
>  		return -ENODEV;
>  
> +	ops = dev->netdev_ops;
> +
>  	switch (cmd) {
>  		case SIOCSIFFLAGS:	/* Set interface flags */
>  			return dev_change_flags(dev, ifr->ifr_flags);

Subject will be changed, sorry.
Seems Julia  is doing "Move a dereference below a NULL test" check,
but why the coccinelle missed this one?