crashes to login screen, uvc related stuff blinks on console

[jorge]

I started getting random crashes to login screen, about twice a day.
When crashes I briefly see some logging output to screen mentioning "UVC Control" or uvcview. I'm not using the webcam when the system crashes.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: lightdm 1.26.0-0ubuntu1
ProcVersionSignature: Ubuntu 5.3.0-61.55~18.04.1-generic 5.3.18
Uname: Linux 5.3.0-61-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.15
Architecture: amd64
CurrentDesktop: Unity:Unity7:ubuntu
Date: Wed Jul 8 11:55:34 2020
InstallationDate: Installed on 2020-02-12 (146 days ago)
InstallationMedia: Ubuntu 18.04.4 LTS "Bionic Beaver" - Release amd64 (20200203.1)
SourcePackage: lightdm
UpgradeStatus: No upgrade log present (probably fresh install)

[jorge (xxopxe)]

Also, this is the very last thing I see on dmesg just after relogging:
```
[469698.684830] Bluetooth: hci0: Hardware error 0x0a
[469698.694845] Bluetooth: hci0: Retrieving Intel exception info failed (-16)
[469698.795777] debugfs: File 'le_min_key_size' in directory 'hci0' already present!
[469698.795781] debugfs: File 'le_max_key_size' in directory 'hci0' already present!
```
(might be unrelated? I have a bluetooth mouse and nothing else)

[jorge (xxopxe)]

I caught the console message on camera:

uvcvideo: Failed to query (GET_INFO) UVC control 15 on unit 1: -32 (exp. 1).

Googling around it seems this is a pretty spammy message, perhaps it is unrelated to what is actually happening.

I can reproduce this crash putting my system under stress, opening a lot of programs and making it swap. At some point it starts stuttering, then crashes. It happens before the swap space is depleted, about 30% of a 2GB swap partition. It's a ThinkPad X1 laptop with SSD.

[jorge (xxopxe)]

After a new reboot I can no longer reproduce this.