Xorg crashed with SIGABRT in OsAbort() from AbortServer() from FatalError("EnterVT failed for screen %d\n") from xf86VTEnter() from WakeupHandler()

StacktraceTop:
 OsAbort () at ../../os/utils.c:1361
 AbortServer () at ../../os/log.c:786
 FatalError (f=f@entry=0x7fe9e8350ee1 "EnterVT failed for screen %d\n") at ../../os/log.c:924
 xf86VTEnter () at ../../../../hw/xfree86/common/xf86Events.c:572
 WakeupHandler (result=result@entry=-1, pReadmask=pReadmask@entry=0x7fe9e85df000 <LastSelectMask>) at ../../dix/dixutils.c:423

Status changed to 'Confirmed' because the bug affects multiple users.

Hello,

For me this started to manifest in the last months; Xorg started crashing randomly after I resume from sleep.
In the meantime, I've installed Xubuntu 18.04 from scratch (keeping only the /home partition) hoping that the problem would be gone. But it isn't.

It seems to be related to the external monitor - ie when there is an external monitor plugged in and I suspend the computer, and when I resume there's only the laptop. But it doesn't always happen, so I don't have clear steps for reproducing. (My bug report was marked as duplicate of this bug, https://bugs.launchpad.net/ubuntu/+source/xorg-server/+bug/1774635)

Hello,

Reproduction steps:

1. connect an external monitor (I connect mine through mini-DisplayPort, and I use only the external monitor, I do NOT use both the laptop screen and the external monitor)
2. with the external monitor connected, suspend the computer (I do it by running xfce4-session-logout --suspend, I have a shortcut for this)
3. with the laptop suspended, disconnect the monitor
4. open the laptop, you'll be shown the Xdm login screen
5. log in
6. Xorg will crash, it will restart, and you'll see again the Xdm login screen

What works (how to avoid the crash)
1. connect an external monitor
2. before suspending the laptop, disconnect the external monitor
3. suspend the laptop
4. open the laptop, everything will be ok

Tracking in https://errors.ubuntu.com/problem/a221de843241aab4d9728bcad808922b71c4a11c

This is happening pretty often to me in Eoan (system info uploaded in bug 1852158 if it might help). I do often use an external monitor, but the crash seldom happens if I suspend with the external monitor as Vlad described. For me, it's more common that I sleep with the external monitor connected, disconnect, wake up and run a script that uses xrandr to enable the laptop display, work for a while, sleep, and then maybe on one of the next 2-3 wakeups (still on the laptop display), the screen will stay black, and when I try to switch VTs to try to get it back, X crashes. It's sporadic and not reliably repeatable but happens often enough to be frustrating.

Maybe fixed in bug 1879893?