[PATCH] mmc: bcm2835: Fix possible NULL ptr dereference in bcm2835_request

[Jaehoon Chung]

On 03/25/2017 10:17 PM, Stefan Wahren wrote:
> This fixes a NULL pointer dereference in case of a MMC request with a
> set block count command and no data.
> 
> Reported-by: Dan Carpenter <dan.carpenter at oracle.com>
> Signed-off-by: Stefan Wahren <stefan.wahren at i2se.com>

Reviewed-by: Jaehoon Chung <jh80.chung at samsung.com>

> ---
>  drivers/mmc/host/bcm2835.c |    3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mmc/host/bcm2835.c b/drivers/mmc/host/bcm2835.c
> index 7d1b0db..1f343a4 100644
> --- a/drivers/mmc/host/bcm2835.c
> +++ b/drivers/mmc/host/bcm2835.c
> @@ -1200,7 +1200,8 @@ static void bcm2835_request(struct mmc_host *mmc, struct mmc_request *mrq)
>  		return;
>  	}
>  
> -	host->use_sbc = !!mrq->sbc && (host->mrq->data->flags & MMC_DATA_READ);
> +	host->use_sbc = !!mrq->sbc && host->mrq->data &&
> +			(host->mrq->data->flags & MMC_DATA_READ);
>  	if (host->use_sbc) {
>  		if (bcm2835_send_command(host, mrq->sbc)) {
>  			if (!host->use_busy)
>