Re: [PATCH 4/6] drivers/net/fs_enet: remove null pointer dereference

[Jeff Garzik <jeff@garzik.org>]

Julia Lawall wrote:
> From: Julia Lawall <julia@diku.dk>
> 
> The following code appears in the function fs_init_instance in the file drivers/net/fs_enet/fs_enet-main.c.
> 
> 	if (fep->ops == NULL) {
> 		printk(KERN_ERR DRV_MODULE_NAME
> 		       ": %s No matching ops found (%d).\n",
> 		       ndev->name, fpi->fs_no);
> 		err = -EINVAL;
> 		goto err;
> 	}
> 
> This code implies that at the point of err, fep->ops can be NULL, so an
> extra test is needed before dereferencing this value.
> 
> 
> This problem was found using the following semantic match
> (http://www.emn.fr/x-info/coccinelle/)
> 
> // <smpl>
> @@
> expression E, E1;
> identifier f;
> statement S1,S2,S3;
> @@
> 
> * if (E == NULL)
> {
>   ... when != if (E == NULL) S1 else S2
>       when != E = E1
> * E->f
>   ... when any
>   return ...;
> }
> else S3
> // </smpl>
> 
> Signed-off-by: Julia Lawall <julia@diku.dk>

applied