Ricardo Salveti <ricardo.salveti@linaro.org> found one place where the
randr code could use the randr screen private data without checking
for null first. This happens when the X server is running with
multiple screens, some of which are randr enabled and some of which
are not. Applications making protocol requests to the non-randr
screens can cause segfaults where the server touches the unset private
structure.
I audited the code and found two more possible problem spots; the
trick to auditing for this issue was to look for functions not taking
a RandR data structure and where there was no null screen private
check above them in the call graph.
Signed-off-by: Keith Packard <keithp@keithp.com>
855003c333