Ubuntu

Diagnosing Intermittent Total System Freezes

Asked by Philip Vetter

Periodically (several times a month) my ubuntu system will experience a hard freeze.
The keyboard and mouse becomes completely unresponsive: cannot toggle the CAPS-LOCK or NumLock LEDs.
The system does not respond to ssh.
If the mouse or keyboard is unplugged and plugged back in again, none of the usual lights come back on.

I find there was a file /var/log/apport.log with contents:
ERROR: apport (pid 334455) Sat Jun 25 09:20:39 2022: called for pid 1566, signal 11, core limit 0, dump mode 1
ERROR: apport (pid 334455) Sat Jun 25 09:20:39 2022: executable: /usr/bin/plasmashell (command line "/usr/bin/plasmashell")
ERROR: apport (pid 334455) Sat Jun 25 09:20:40 2022: gdbus call error: Error: GDBus.Error:org.freedesktop.DBus.Error.ServiceUnknown: The name org.gnome.SessionManager was not provided by any .service files

ERROR: apport (pid 334455) Sat Jun 25 09:20:40 2022: debug: session gdbus call:
ERROR: apport (pid 334455) Sat Jun 25 09:20:50 2022: wrote report /var/crash/_usr_bin_plasmashell.1000.crash

There is a 58MB file /var/crash/_usr_bin_plasmashell.1000.crash with the same timestamp.

/var/crash/_usr_bin_plasmashell.1000.crash
although it is not clear whether it was created at the system freeze or prior to it (I was away when it froze.)

Q1: How can I diagnose the cause of the system freeze?
Q2: How can I diagnose the cause of the plasmashell crash?
Q3: What is the proper way to report the _usr_bin_plasmashell.1000.crash ?

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Manfred Hampl (m-hampl) said : 		#1

Q3: What is the proper way to report the _usr_bin_plasmashell.1000.crash ?

https://help.ubuntu.com/community/ReportingBugs#Reporting_a_crash_when_no_message_shows_up_and_crash_files_created

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Philip Vetter (pvetter) said : 		#2

I have reported as shown on the page. Is there any way for me to follow up on the report?

I still would appreciate help on diagnosing the system freezes.

Memory testing has never shown any errors.
SysReq does not seem to work, the keyboard is unresponsive. Cannot change to virtual consoles.

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Philip Vetter (pvetter) said : 		#3

https://wiki.ubuntu.com/Kernel/CrashdumpRecipe
suggests
sudo apt-get install linux-crashdump
This triggers a dialog Configuring kexec-tools ├───────────────────────────────────────────────────────────────────┐
 │ │
 │ If you choose this option, a system reboot will trigger a restart into a kernel loaded by kexec instead of going through the full system boot loader process. │
 │ │
 │ Should kexec-tools handle reboots?

I tried finding information via
man kexec-tools
man: can't set the locale; make sure $LC_* and $LANG are correct
No manual entry for kexec-tools
a@black:~$ info kexec-tools
info: No menu item 'kexec-tools' in node '(dir)Top'

What are the implications of the two choices (Yes/No)?

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Manfred Hampl (m-hampl) said : 		#4

To your last comment:
What do you want to achieve?

In the kexec-tools there are man pages for coldreboot, kexec and vmcore-dmesg
Maybe you should also look at https://manpages.ubuntu.com/manpages/jammy/en/man8/kdump-config.8.html

Remark:

"man kexec-tools
man: can't set the locale; make sure $LC_* and $LANG are correct"

There seems to be a configuration error with respect to locale settings in your system.
I do not think that this can lead to system freezes, but you should get that corrected.

Can you help with this problem?

Provide an answer of your own, or ask Philip Vetter for more information if necessary.

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