Comment 5 for bug 1689538

Since upgrading to Ubuntu 17-04, I have been experiencing the same problem with Firefox (and other network applications, even ping). No reaction to kill, so probably hanging in a syscall. I also have these "CPU… stuck for 22s" messages in syslog, every 28 – 30 seconds. And the process taking 100% of a CPU is usually firefox, not khugepaged, so maybe the problem is not a duplicate of bug #1674838.

While in such cases my system cannot be shutdown regularly it still accepts magic SysRq (REISUB).