Bug 1377987

Created attachment 1203185 [details]
gdm log

[snip]
X Error of failed request:  BadValue (integer parameter out of range for operation)
Major opcode of failed request:  113 (X_KillClient)
Value in failed request:  0x800000
Serial number of failed request:  25
Current serial number in output stream:  278
gdm.service: main process exited, code=exited, status=1/FAILURE
Process exit status: 0

...
Unit gdm.service entered failed state.
Triggering OnFailure= dependencies of gdm.service.
gdm.service failed.
gdm.service holdoff time over, scheduling restart.
Starting GNOME Display Manager...

Regression was introduced in gdm-3.14.2-18.el7.

Not really sure what happened here… on my local branch I have:

+                gdm_error_trap_push ();
+
+                /* Kill every client but ourselves, then close our own connection
+                 */
+                for (client = 0;
+                     client <= highest_client;
+                     client += client_increment) {
+
+                        if (client != setup->resource_id_base)
+                                XKillClient (slave->priv->server_display, client);
+                }
+
+                XCloseDisplay (slave->priv->server_display);
+                gdm_error_trap_pop ();


but on the branch I committed i have:

+                /* Kill every client but ourselves, then close our own connection
+                 */
+                for (client = 0;
+                     client <= highest_client;
+                     client += client_increment) {
+
+                        if (client != setup->resource_id_base)
+                                XKillClient (slave->priv->server_display, client);
+                }
+
+                XCloseDisplay (slave->priv->server_display);


Note the missing error_trap_push/pop calls. I don't really understand how they fell out of the patch, but I clearly bungled it somehow

The issue is fixed.

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://rhn.redhat.com/errata/RHBA-2016-2451.html