Adding the VirtualBox log. UPD: Please, notify me If I need to run the `apport-collect 2022097` at the normal ubuntu state, it seems like I do not.
** Attachment added: "VBox.log" https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2022097/+attachment/5677207/+files/VBox.log ** Changed in: linux (Ubuntu) Status: Incomplete => Confirmed -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/2022097 Title: Ubuntu 20.04 Stuck at reboot in Virtualbox kernel version 5.4.0-149-generic #166 SMP Status in linux package in Ubuntu: Confirmed Bug description: The problem occurs whilst sequentially rebooting the Ubuntu20.04 freshly installed inside the VirtualBox. Host os: ``` No LSB modules are available. Description: Ubuntu 23.04 Release: 23.04 ``` Guest os: ``` Description: Ubuntu 20.04.6 LTS Release: 20.04 ``` VirtualBox version: ``` VirtualBox Graphical User Interface Version 7.0.6_Ubuntu r155176 7.0.6_Ubuntur155176 ``` Steps to reproduce: reboot the virtual machine several times via the `reboot` command. Actual behavior: At a certain reboot, the Ubuntu gets stuck with the last message being `[ 0.000000] Linux agpgart interface v0.103`. After that the machine gets stuck. Before that there are significant discrepancies in timestamp. Expected behavior: Normal boot. The issue consistently reproduces on different VirtualBox versions (from 6.1.28r147628 to 7.0) and on different host kernel versions, also tried 5.16 and 5.19 kernels. The issue persists after changing various VirtualBox VM options. Disabling sound control, disabling graphics, disabling PAE/NX, VT/X nested virtualization and KVM nested paging does not make the issue go away. Enabling/disabling serial port does not influence the issue. Changing the VirtualBox System/Enable Hardware Clock in UTC time to unchecked does not help too. Whilst being stuck the kernel inside the VM ignores sysrq sent via: ``` VM="Ubuntu" PRESS="26" RELEASE=$(printf "%X\n" $((0x${PRESS} + 0x80))) VBoxManage controlvm "$VM" keyboardputscancode 1d 38 54 "${PRESS}" "${RELEASE}" d4 b8 9d ``` (All the other sysrq interrupts were tried, in order to make sure I have double checked that the sysrq was enabled, and sent all sysrq's to the normally booted VM, and it did work). Kernel rebuilt with debug symbols does not affect the problem. Changing the verbosity level did not yield any additional results. Enabling/disabling KASLR and ASLR did not yield any results. Changing the clocksource to kvm-clock , tsc and acpi_pm did not fix the problem. SIGNIFICANT NOTE: The problem goes away in case of > 2 CPU and 1GB ram. Attaching kdb/kgdb does not seem possible since the sysrq is being ignored. The issue does reproduce for other users: https://www.reddit.com/r/linuxquestions/comments/ols6f1/ubuntu_server_2004_boot_suddenly_it_freezes_at/ After a bit of printk I have managed to find the source of the problem and take a stack trace with the VirtualBox debugger. The problem is the `blk_mq_freeze_queue_wait` being stuck at the loop driver initialization. ``` # RBP Ret SS:RBP Ret RIP CS:RIP / Symbol [line] 00 ffffc90000013c80 0000:ffffc90000013c90 ffffffff81aaf4ba kallsyms!blk_mq_freeze_queue_wait retn/64 01 ffffc90000013c90 0000:ffffc90000013cc0 ffffffff81ab0d47 kallsyms!blk_mq_freeze_queue+e retn/64 02 ffffc90000013cc0 0000:ffffc90000013ce0 ffffffff81ab0f29 kallsyms!wbt_init+1af retn/64 03 ffffc90000013ce0 0000:ffffc90000013d28 ffffffff81aaef13 kallsyms!wbt_enable_default+b6 retn/64 04 ffffc90000013d28 0000:ffffc90000013d90 ffffffff814f2760 kallsyms!blk_register_queue+358 retn/64 05 ffffc90000013d90 0000:ffffc90000013da0 ffffffff814f27a3 kallsyms!__device_add_disk+450 retn/64 06 ffffc90000013da0 0000:ffffc90000013dd8 ffffffff81aca41c kallsyms!device_add_disk+13 retn/64 07 ffffc90000013dd8 0000:ffffc90000013e10 ffffffff82d0f072 kallsyms!loop_add+327 retn/64 08 ffffc90000013e10 0000:ffffc90000013e88 ffffffff810037da kallsyms!loop_init+134 retn/64 09 ffffc90000013e88 0000:ffffc90000013f38 ffffffff82ca240c kallsyms!do_one_initcall+4a retn/64 0a ffffc90000013f38 0000:ffffc90000013f48 ffffffff81aedd6e kallsyms!kernel_init_freeable+1e6 retn/64 0b ffffc90000013f48 0000:0000000000000000 ffffffff81c00255 kallsyms!kernel_init+e retn/64 0c 0000000000000000 0000:0000000000000000 0000000000000000 kallsyms!ret_from_fork+35 ``` blk_mq_freeze_queue_wait just calls the `wait_event` for the `percpu_ref_is_zero(&q->q_usage_counter)`, which is not being zero before the wait. Inside the wait_event macro, prepare_to_wait_event function is reached, finish_wait is not reached. (Checked with the debuggers breakpoints). Thank you for your efforts in addressing this matter. I appreciate your attention and assistance in resolving the issue. If there is any additional information or logs that would be helpful in investigating the problem, please let me know. I have confidence in your expertise and appreciate your support. Best regards. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2022097/+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
