Re: [PATCH] UWB: Return UWB_RSV_ALLOC_NOT_FOUND rather than crashing on NULL dereference if kzalloc fails

[David Vrabel <david.vrabel@csr.com>]

Jesper Juhl wrote:
> Hi,
> 
> Crashing on a null pointer deref is never a nice thing to do. It seems to 
> me that it's better to simply return UWB_RSV_ALLOC_NOT_FOUND if kzalloc() 
> fails in uwb_rsv_find_best_allocation().

This is fine.

struct uwb_rsv_alloc_info is not that large (about 414 bytes I think) so
it could possibly go on the stack and avoid the allocation.

Acked-by: David Vrabel <david.vrabel@csr.com>

Greg, seeing as I'm not maintaining the UWB subsystem any more do you
want to pick this (and future) UWB patches?

David

> I may be wrong since I have no way to test this (except compile test) and 
> this is unknown code to me, so please review carefully.
> 
> Please CC me on replies.
> 
> 
> Signed-off-by: Jesper Juhl <jj@chaosbits.net>
> ---
>  allocator.c |    3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/uwb/allocator.c b/drivers/uwb/allocator.c
> index 436e4f7..e45e673 100644
> --- a/drivers/uwb/allocator.c
> +++ b/drivers/uwb/allocator.c
> @@ -326,7 +326,8 @@ int uwb_rsv_find_best_allocation(struct uwb_rsv *rsv, struct uwb_mas_bm *availab
>  	int bit_index;
>  
>  	ai = kzalloc(sizeof(struct uwb_rsv_alloc_info), GFP_KERNEL);
> -	
> +	if (!ai)
> +		return UWB_RSV_ALLOC_NOT_FOUND;
>  	ai->min_mas = rsv->min_mas;
>  	ai->max_mas = rsv->max_mas;
>  	ai->max_interval = rsv->max_interval;
-- 
David Vrabel, Senior Software Engineer, Drivers
CSR, Churchill House, Cambridge Business Park,  Tel: +44 (0)1223 692562
Cowley Road, Cambridge, CB4 0WZ                 http://www.csr.com/


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