diff options
authorPeter Hutterer <>2010-08-23 13:20:09 +1000
committerPeter Hutterer <>2010-09-27 09:41:41 +0200
commit72e3e6f4a7690f70a6b5f7689633cdea859535e1 (patch)
parent0f3a0ab1f01ec5314ccb0bfb932c49f8c61b9866 (diff)
dix: fix crash when removing devices on a buttonless MD pointer (#29669)
If the master does not have a button class, recalculating the number of buttons required for this master dereferences a NULL pointer. Guard against this, if the master pointer doesn't have a button class, it doesn't need to update it's number of buttons. Reproducible: Two devices on the same master, device NB with axes but no buttons, device A+B with axes and button . If NB was the last one to send an event through the master when A+B is removed from the server, master->button is NULL and leads to the above NULL-pointer dereference. X.Org Bug 29669 <> Signed-off-by: Peter Hutterer <> Reviewed-by: Keith Packard <> (cherry picked from commit ff055506f0cbb852bed17acb9f9bbf1d715a854e)
1 files changed, 1 insertions, 1 deletions
diff --git a/dix/devices.c b/dix/devices.c
index 2e65a041d..0bd9b75e6 100644
--- a/dix/devices.c
+++ b/dix/devices.c
@@ -2336,7 +2336,7 @@ RecalculateMasterButtons(DeviceIntPtr slave)
maxbuttons = max(maxbuttons, dev->button->numButtons);
- if (master->button->numButtons != maxbuttons)
+ if (master->button && master->button->numButtons != maxbuttons)
int i;
DeviceChangedEvent event;