Re: [PATCH v3] drivers/misc/sgi-gru: fix dereference of ERR_PTR

[Dimitri Sivanich <sivanich@sgi.com>]

Acked-by: Dimitri Sivanich <sivanich@sgi.com>

On Fri, Sep 04, 2015 at 09:56:20AM +0530, Sudip Mukherjee wrote:
> gru_alloc_gts() can fail and it can return ERR_PTR(errvalue). We should
> not dereference it if it has returned error. And incase it has returned
> error then wait for some time and try again.
> 
> Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org>
> ---
> 
> v3: compact code for if logic
> v2: on error retry after msleep(1).
> v1: returned error.
> 
> 
>  drivers/misc/sgi-gru/grukservices.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/misc/sgi-gru/grukservices.c b/drivers/misc/sgi-gru/grukservices.c
> index 490b79a..7812e34 100644
> --- a/drivers/misc/sgi-gru/grukservices.c
> +++ b/drivers/misc/sgi-gru/grukservices.c
> @@ -160,7 +160,12 @@ static void gru_load_kernel_context(struct gru_blade_state *bs, int blade_id)
>  	down_write(&bs->bs_kgts_sema);
>  
>  	if (!bs->bs_kgts) {
> -		bs->bs_kgts = gru_alloc_gts(NULL, 0, 0, 0, 0, 0);
> +		do {
> +			bs->bs_kgts = gru_alloc_gts(NULL, 0, 0, 0, 0, 0);
> +			if (!IS_ERR(bs->bs_kgts))
> +				break;
> +			msleep(1);
> +		} while (true);
>  		bs->bs_kgts->ts_user_blade_id = blade_id;
>  	}
>  	kgts = bs->bs_kgts;
> -- 
> 1.9.1