Re: [PATCH 1/6] arch/ia64/kernel: remove null pointer dereference

["Simon Holm Thøgersen" <odie@cs.aau.dk>]

man, 12 05 2008 kl. 15:37 +0200, skrev Julia Lawall:
> From: Julia Lawall <julia@diku.dk>
> 
> If data is NULL, it is not possible to access data->ret.
> 
> The problem was detected 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>
> 
> ---
> 
> diff -u -p a/arch/ia64/kernel/palinfo.c b/arch/ia64/kernel/palinfo.c
> --- a/arch/ia64/kernel/palinfo.c	2008-05-09 16:46:57.000000000 +0200
> +++ b/arch/ia64/kernel/palinfo.c	2008-05-12 08:43:35.000000000 +0200
> @@ -902,7 +902,6 @@ palinfo_smp_call(void *info)
>  	palinfo_smp_data_t *data = (palinfo_smp_data_t *)info;
>  	if (data = NULL) {
>  		printk(KERN_ERR "palinfo: data pointer is NULL\n");
> -		data->ret = 0; /* no output */
>  		return;
>  	}
>  	/* does this actual call */
> --

The whole if block should just be deleted, as info is never NULL. There
is only palinfo_handle_smp as (indirect) user of palinfo_smp_call (by
way of smp_call_function_single) and surely palinfo_smp_call never pass
NULL.


Simon Holm Th√∏gersen

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