xfree86: Do not use uninitialized pointer during probe

Commits b5dffbb and d75ffcd introduce code in xf86platformProbe() that
references a member of xf86configptr.  However, when using the
"-configure" option, xf86configptr may not be initialized when
xf86platformProbe() is called.

Avoid referencing a member of xf86configptr if uninitialized.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=100405
Signed-off-by: Jeff Smith <whydoubt@gmail.com>
Reviewed-by: Adam Jackson <ajax@redhat.com>

1 files changed, 4 insertions, 3 deletions

diff --git a/hw/xfree86/common/xf86platformBus.c b/hw/xfree86/common/xf86platformBus.c
index 844bf7e93..cef47da03 100644
--- a/hw/xfree86/common/xf86platformBus.c
+++ b/hw/xfree86/common/xf86platformBus.c
@@ -276,7 +276,8 @@ xf86platformProbe(void)
 {
     int i;
     Bool pci = TRUE;
-    XF86ConfOutputClassPtr cl;
+    XF86ConfOutputClassPtr cl, cl_head = (xf86configptr) ?
+            xf86configptr->conf_outputclass_lst : NULL;
     char *old_path, *path = NULL;
 
     config_odev_probe(xf86PlatformDeviceProbe);
@@ -296,7 +297,7 @@ xf86platformProbe(void)
          * Deal with OutputClass ModulePath directives, these must be
          * processed before we do any module loading.
          */
-        for (cl = xf86configptr->conf_outputclass_lst; cl; cl = cl->list.next) {
+        for (cl = cl_head; cl; cl = cl->list.next) {
             if (!OutputClassMatches(cl, &xf86_platform_devices[i]))
                 continue;
 
@@ -317,7 +318,7 @@ xf86platformProbe(void)
     /* First see if there is an OutputClass match marking a device as primary */
     for (i = 0; i < xf86_num_platform_devices; i++) {
         struct xf86_platform_device *dev = &xf86_platform_devices[i];
-        for (cl = xf86configptr->conf_outputclass_lst; cl; cl = cl->list.next) {
+        for (cl = cl_head; cl; cl = cl->list.next) {
             if (!OutputClassMatches(cl, dev))
                 continue;