I also have this problem. After the automatic update from kernel 5.8 to 5.11 this error occurs. The error only occurs during a cold boot. When rebooting the system, this error does not occur.
Here an interesting thread about this problem: https://bbs.minisforum.com/threads/ubuntu-stuck-booting.1830/ ** Attachment added: "logs_and_infos.zip" https://bugs.launchpad.net/ubuntu/+source/linux-hwe-5.11/+bug/1931001/+attachment/5525689/+files/logs_and_infos.zip -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux-hwe-5.11 in Ubuntu. https://bugs.launchpad.net/bugs/1931001 Title: kernel: watchdog: BUG: soft lockup - CPU#3 stuck for 22s! Status in linux-hwe-5.11 package in Ubuntu: Confirmed Bug description: Ubuntu 20.04 LTS and Ubuntu 21.04 occasionally boots with very bad performance and very unresponsive to user input on Lenovo laptop Lenovo 300e 2nd Gen 81M9 (LENOVO_MT_81M9_BU_idea_FM_300e 2nd G). When this happens you can read this kind of messages on journal: --- root@alumne-1-58:~# journalctl | grep "BUG: soft" may 20 21:44:35 alumne-1-58 kernel: watchdog: BUG: soft lockup - CPU#3 stuck for 22s! [swapper/3:0] may 20 21:44:35 alumne-1-58 kernel: watchdog: BUG: soft lockup - CPU#3 stuck for 22s! [swapper/3:0] may 22 09:33:34 alumne-1-58 kernel: watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [swapper/0:0] may 24 16:45:14 alumne-1-58 kernel: watchdog: BUG: soft lockup - CPU#1 stuck for 23s! [prometheus-node:4220] may 24 16:45:14 alumne-1-58 kernel: watchdog: BUG: soft lockup - CPU#0 stuck for 23s! [swapper/0:0] jun 03 00:01:09 alumne-1-58 kernel: watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [swapper/0:0] jun 03 00:01:09 alumne-1-58 kernel: watchdog: BUG: soft lockup - CPU#0 stuck for 23s! [swapper/0:0] jun 03 00:01:09 alumne-1-58 kernel: watchdog: BUG: soft lockup - CPU#1 stuck for 22s! [swapper/1:0] jun 03 00:01:09 alumne-1-58 kernel: watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [swapper/0:0] jun 03 00:02:15 alumne-1-58 kernel: watchdog: BUG: soft lockup - CPU#0 stuck for 21s! [swapper/0:0] jun 05 08:22:58 alumne-1-58 kernel: watchdog: BUG: soft lockup - CPU#3 stuck for 22s! [irq/138-iwlwifi:1044] jun 05 08:25:06 alumne-1-58 kernel: watchdog: BUG: soft lockup - CPU#2 stuck for 22s! [swapper/2:0] jun 05 08:25:06 alumne-1-58 kernel: watchdog: BUG: soft lockup - CPU#3 stuck for 22s! [irq/138-iwlwifi:1044] jun 05 08:26:42 alumne-1-58 kernel: watchdog: BUG: soft lockup - CPU#1 stuck for 23s! [lxd:3975] jun 05 08:26:42 alumne-1-58 kernel: watchdog: BUG: soft lockup - CPU#2 stuck for 23s! [swapper/2:0] jun 05 08:26:42 alumne-1-58 kernel: watchdog: BUG: soft lockup - CPU#3 stuck for 23s! [irq/138-iwlwifi:1044] jun 05 08:27:38 alumne-1-58 kernel: watchdog: BUG: soft lockup - CPU#3 stuck for 23s! [irq/138-iwlwifi:1044] jun 05 08:28:34 alumne-1-58 kernel: watchdog: BUG: soft lockup - CPU#3 stuck for 22s! [irq/138-iwlwifi:1044] jun 05 08:29:46 alumne-1-58 kernel: watchdog: BUG: soft lockup - CPU#3 stuck for 22s! [irq/138-iwlwifi:1044] root@alumne-1-58:~# --- Usually if you reboot everything works fine but it's very annoying when happens. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-hwe-5.11/+bug/1931001/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp