From 21eda7464d0e13ac6558edaf6531c3d3251e05df Mon Sep 17 00:00:00 2001 From: Tobias Stoeckmann Date: Sun, 12 Mar 2017 14:21:38 +0100 Subject: [PATCH] dmx: Fix null pointer dereference 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. Reviewed-by: Adam Jackson --- 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. */