Comment 0 for bug 1683091

Upgraded from xenial to zesty recently.

I was using a Firefox instance, one which is a part of Tor Browser Bundled. First, the application window grayed out, then the whole system froze for something like 30 seconds (I tried to switch to VT1 to no avail), then the process got killed.

Well, not exactly killed.

The grayed-out window is still there, `xprop | grep PID` and clicking on it gives:

```
_NET_WM_PID(CARDINAL) = 13
```

PID 13 is a child of kthreadd:

```
$ ps -A | awk '$1 == "13" { print }'
   13 ? 00:00:00 cpuhp/1
```

And this is how the relevant part of `ps -AH` with the "killed" process looks like:

```
 5709 pts/11 00:00:00 firejail
 5710 pts/11 00:00:00 firejail
 5725 pts/11 00:00:00 bash
 5736 pts/11 00:56:49 firefox <defunct>
 5769 pts/11 00:00:24 tor
```

I checked syslog and dmesg. Both of them have an interesting and identical message, which I add as dmesg.log.

I also add the output of `cat /proc/version_signature` as version.log.

I don't think `sudo lspci -vnvn` is relevant here, so I'm not gonna share it unless absolutely necessary.

The crashed process will be there for something like 2 or 3 days at least (I don't restart my laptop often), so feel free to ask me to manipulate or query it somehow, if necessary.