I was able to reproduce the lockup on the test kernel (6.17.0-1022-generic). It's much harder to trigger now, the fix has significantly reduced the frequency, but I got lucky and it happened on the first attempt after setting up remote logging.
Setup: Enabled debug flags on the test machine: echo 0x4 | sudo tee /sys/module/drm/parameters/debug echo 'file drivers/usb/typec/class.c +pt' | sudo tee /sys/kernel/debug/dynamic_debug/control echo 'file drivers/usb/typec/ucsi/ucsi.c +pt' | sudo tee /sys/kernel/debug/dynamic_debug/control echo 'file drivers/usb/typec/ucsi/displayport.c +pt' | sudo tee /sys/kernel/debug/dynamic_debug/control Captured dmesg remotely from a second machine: ssh [email protected] 'sudo dmesg -w' | tee -a ~/monitor-crash-$(date +%Y%m%d).log Reproduction: Unplugged and replugged the USB-C daisy chain (Dell U2721DE → Dell U2421HE). System locked up. Confirmed kernel: $ uname -r 6.17.0-1022-generic Attached: monitor-crash-20260323.log (remote dmesg capture) I will attach the output of journalctl -b -1 in a follow-up comment. ** Attachment added: "monitor-crash-20260323.log" https://bugs.launchpad.net/ubuntu/+source/linux-hwe-6.17/+bug/2141225/+attachment/5955247/+files/monitor-crash-20260323.log -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2141225 Title: Kernel panic when connecting USB-C Dell monitors on Ubuntu kernel 6.17.0-14-generic To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-hwe-6.17/+bug/2141225/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
