This is a Dell T7910 workstation with Ubuntu 22.04 (latest update). Almost each day it freezes one or more time. Mouse and keyboard don't work when a freeze occurs. When it occurs, the screen may be black or I may see a normal but frozen desktop. All diagnostic tests I've performed so far, including CPU and GPU stress tests, show no issues. Today at about 6:15 PM I noticed it has occurred again and I immediately restarted the system. I think the following extract from the syslog shows when it occurred:
May 9 15:30:28 kant gnome-shell[2315]: Window manager warning: Overwriting existing binding of keysym 37 with keysym 37 (keycode 10).May 9 15:32:34 kant gnome-shell[2315]: meta_window_set_stack_position_no_sync: assertion 'window->stack_position >= 0' failedMay 9 15:35:01 kant CRON[8946]: (root) CMD (command -v debian-sa1 > /dev/null && debian-sa1 1 1)May 9 15:42:53 kant NetworkManager[1325]: <info> [1715256773.8910] dhcp4 (wlp11s2): state changed new lease, address=192.168.1.4May 9 15:42:53 kant kernel: [ 7219.134069] audit: type=1400 audit(1715256773.890:123): apparmor="DENIED" operation="open" class="file" profile="snap.skype.skype" name="/sys/devices/virtual/net/lo/speed" pid=6531 comm="skypeforlinux" requested_mask="r" denied_mask="r" fsuid=1000 ouid=0May 9 15:42:53 kant kernel: [ 7219.134120] audit: type=1400 audit(1715256773.890:124): apparmor="DENIED" operation="open" class="file" profile="snap.skype.skype" name="/sys/devices/pci0000:00/0000:00:1c.1/0000:09:00.0/net/enp9s0/speed" pid=6531 comm="skypeforlinux" requested_mask="r" denied_mask="r" fsuid=1000 ouid=0May 9 15:42:53 kant kernel: [ 7219.134182] audit: type=1400 audit(1715256773.890:125): apparmor="DENIED" operation="open" class="file" profile="snap.skype.skype" name="/sys/devices/pci0000:00/0000:00:19.0/net/enp0s25/speed" pid=6531 comm="skypeforlinux" requested_mask="r" denied_mask="r" fsuid=1000 ouid=0May 9 15:42:53 kant kernel: [ 7219.134230] audit: type=1400 audit(1715256773.890:126): apparmor="DENIED" operation="open" class="file" profile="snap.skype.skype" name="/sys/devices/pci0000:00/0000:00:1c.3/0000:0a:00.0/0000:0b:02.0/net/wlp11s2/speed" pid=6531 comm="skypeforlinux" requested_mask="r" denied_mask="r" fsuid=1000 ouid=0May 9 15:45:01 kant CRON[9045]: (root) CMD (command -v debian-sa1 > /dev/null && debian-sa1 1 1)May 9 18:16:28 kant systemd-modules-load[797]: Inserted module 'lp'May 9 18:16:28 kant systemd-modules-load[797]: Inserted module 'ppdev'May 9 18:16:28 kant systemd-modules-load[797]: Inserted module 'parport_pc'May 9 18:16:28 kant systemd-modules-load[797]: Inserted module 'msr'May 9 18:16:28 kant systemd[1]: Starting Flush Journal to Persistent Storage...May 9 18:16:28 kant systemd[1]: Finished Create Static Device Nodes in /dev.May 9 18:16:28 kant systemd[1]: Reached target Preparation for Local File Systems.May 9 18:16:28 kant mtp-probe: checking bus 3, device 3: "/sys/devices/pci0000:00/0000:00:14.0/usb3/3-11"May 9 18:16:28 kant systemd[1]: Mounting Mount unit for bare, revision 5...May 9 18:16:28 kant kernel: [ 0.000000] microcode: updated early: 0xb000038 -> 0xb000040, date = 2021-05-19May 9 18:16:28 kant mtp-probe: checking bus 3, device 5: "/sys/devices/pci0000:00/0000:00:14.0/usb3/3-13/3-13.1"May 9 18:16:28 kant kernel: [ 0.000000] Linux version 6.5.0-28-generic (buildd@lcy02-amd64-098) (x86_64-linux-gnu-gcc-12 (Ubuntu 12.3.0-1ubuntu1~22.04) 12.3.0, GNU ld (GNU Binutils for Ubuntu) 2.38) #29~22.04.1-Ubuntu SMP PREEMPT_DYNAMIC Thu Apr 4 14:39:20 UTC 2 (Ubuntu 6.5.0-28.29~22.04.1-generic 6.5.13)May 9 18:16:28 kant kernel: [ 0.000000] Command line: BOOT_IMAGE=/boot/vmlinuz-6.5.0-28-generic root=UUID=19de2f29-8471-4298-91db-8a06824b550a ro quiet splash vt.handoff=7Yesterday, I used hw-probe to probe the system. Here is its report: http://linux-hardware.org/?probe=ff480889b4
