this is (mostly) fixed in 2 commits, from the original bug (bug 1505564) kernel level commit 5a3a466ae3c86ad6b8fc36c2efc5f541ef0ed89e (from git://kernel.ubuntu.com/ubuntu/ubuntu-trusty.git lts-backport-vivid) partially fixes this problem, by using the console_may_schedule var correctly. The recent upstream commit 6b97a20d3a7909daa06625d4440c2c52d7bf08d7 (from upstream) completes fixing the problem, by setting console_may_schedule correctly.
-- 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/1534216 Title: lots of printk to serial console can hang system for long time Status in linux package in Ubuntu: In Progress Bug description: 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. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1534216/+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
