Public bug reported: This is a clone from bug 1505564, to track the separate issue of the serial port driver failing to schedule itself off its cpu.
The original bug's problem was caused by the kernel spamming a huge number of error messages in a certain situation. Normally, that would not be a problem, but in this case the system is virtualized, and logs over its serial port. When the massive number of kernel messages are sent to the serial port driver, it can't keep up, so sending all the log messages can take a very long time - minutes or longer - and the serial port driver fails to schedule itself off the cpu it's using during that time. That results in other cpus hanging, waiting for the serial port driver's cpu to become avaiable. I'll update the bug with more details as I debug. ** Affects: linux (Ubuntu) Importance: Undecided Assignee: Dan Streetman (ddstreet) Status: In Progress ** Tags: sts ** Changed in: linux (Ubuntu) Assignee: (unassigned) => Dan Streetman (ddstreet) ** Changed in: linux (Ubuntu) Status: New => In Progress -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1534216 Title: serial port driver in some virtual systems can hang To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1534216/+subscriptions -- ubuntu-bugs mailing list firstname.lastname@example.org https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs