Re: [PATCH] ath9k: fix NULL-deref in hw_per_calibration() for ar9002

["John W. Linville" <linville@tuxdriver.com>]

On Wed, May 07, 2014 at 09:22:58AM +0200, David Herrmann wrote:
> ah->caldata may be NULL if no channel is selected. Check for that before
> accessing it.
> 
> Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
> ---
> Hi
> 
> This is _definitely_ only a workaround, given that no-one guarantees ah->caldata
> is freed while we run in hw_per_calibration(). However, this patch fixes serious
> kernel panics with wifi-P2P on my machine.
> 
> I'm not sure why ah->caldata can be NULL, but it definitely is. I think the
> correct fix would be to synchronously stop any running hw-calibration before
> setting ah->caldata to NULL. I don't know whether/where that is done, so I wrote
> this small workaround.
> 
> Thanks
> David

Is there any hope for getting a more complete fix from the ath9k guys
in short order?

John

> 
>  drivers/net/wireless/ath/ath9k/ar9002_calib.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/wireless/ath/ath9k/ar9002_calib.c b/drivers/net/wireless/ath/ath9k/ar9002_calib.c
> index cdc7400..4667ab9 100644
> --- a/drivers/net/wireless/ath/ath9k/ar9002_calib.c
> +++ b/drivers/net/wireless/ath/ath9k/ar9002_calib.c
> @@ -99,14 +99,16 @@ static bool ar9002_hw_per_calibration(struct ath_hw *ah,
>  				}
>  
>  				currCal->calData->calPostProc(ah, numChains);
> -				caldata->CalValid |= currCal->calData->calType;
> +				if (caldata)
> +					caldata->CalValid |= currCal->calData->calType;
> +
>  				currCal->calState = CAL_DONE;
>  				iscaldone = true;
>  			} else {
>  				ar9002_hw_setup_calibration(ah, currCal);
>  			}
>  		}
> -	} else if (!(caldata->CalValid & currCal->calData->calType)) {
> +	} else if (caldata && !(caldata->CalValid & currCal->calData->calType)) {
>  		ath9k_hw_reset_calibration(ah, currCal);
>  	}
>  
> -- 
> 1.9.2
> 
> 

-- 
John W. Linville		Someday the world will need a hero, and you
linville@tuxdriver.com			might be all we have.  Be ready.