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 <http://bugs.freedesktop.org/show_bug.cgi?id=29669> Signed-off-by: Peter Hutterer <[email protected]> --- dix/devices.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/dix/devices.c b/dix/devices.c index 2e65a04..0bd9b75 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; -- 1.7.2.1 _______________________________________________ [email protected]: X.Org development Archives: http://lists.x.org/archives/xorg-devel Info: http://lists.x.org/mailman/listinfo/xorg-devel
