[PATCH] dmx: Fix null pointer dereference

[walter harms]

Am 12.03.2017 14:21, schrieb Tobias Stoeckmann:
> A null pointer dereference can occur in dmxSync, because TimerForce
> does not handle a null pointer.
> 
> dmxSyncTimer is set to NULL a few lines above on a certain condition,
> which happened on my machine. The explicit NULL check allowed me to
> start Xdmx again without a segmentation fault.
> ---
>  hw/dmx/dmxsync.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/hw/dmx/dmxsync.c b/hw/dmx/dmxsync.c
> index 1bc242343..b55c9ddf3 100644
> --- a/hw/dmx/dmxsync.c
> +++ b/hw/dmx/dmxsync.c
> @@ -182,7 +182,7 @@ dmxSync(DMXScreenInfo * dmxScreen, Bool now)
>  
>          /* Do sync or set time for later */
>          if (now || !dmxScreen) {
> -            if (!TimerForce(dmxSyncTimer))
> +            if (dmxSyncTimer == NULL || !TimerForce(dmxSyncTimer))
>                  dmxSyncCallback(NULL, 0, NULL);
>              /* At this point, dmxSyncPending == 0 because
>               * dmxSyncCallback must have been called. */



why not patch TimerForce() and solve the problem for once and any one ?

re,
 wh