Hi Jitendra, I am sorry for the delay - I've tried to reproduce both using regular SCSI device in a virtual machine and by using iSCSI, and neither was a successful reproducer. Based on the stack traces I see in your "echo w" output, it seems to be related with your special iSCSI target. Also, was the SCSI device removed holding a btrfs filesystem?
I don't see any benefit in keeping the machine in this state, please go ahead and repurpose that to try reproducing; but I'd like you to set kdump before, if possible, so we collect the dump over there. Also, please try using the latest Bionic kernel 4.15.0-139. In order to setup kdump, please run the following as root user: 1) apt-get update; apt-get install linux-crashdump 2) Answer the installer questions using the default responses 3) Edit the file "/etc/default/grub.d/kdump-tools.cfg" and change the crashkernel setting to be something like "crashkernel=440M" - you can try a bit less memory, but since it's hard to reproduce, it's safer to keep a large value to prevent kdump failure 4) Please execute, as root user: echo "kernel.hung_task_panic=1" >> /etc/sysctl.conf 5) Reboot the machine and check the output of "kdump-config show" - it should show that kdump is ready. If so, please try a dummy kdump to check if it's working, by running: echo 1 > /proc/sys/kernel/sysrq echo c > /proc/sysrq-trigger 6) If it works, the node should be rebooted and you should have a dump collected on /var/crash/ . In that case, go ahead and try to reproduce. Thanks for your effort here - I'll be out next week, as soon as I'm back I'll continue the work. Cheers, Guilherme -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1914456 Title: 120 sec kernel timeout is seen during SCSI remove_device. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/open-iscsi/+bug/1914456/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
