On Sun, Jul 01, 2012 at 01:16:13AM -0700, john stultz wrote:On Sat, Jun 30, 2012 at 5:57 PM, Jan Engelhardt <jengelh@xxxxxxx> wrote:I can't vouch for whether this is the problem or not, but be veryThis year's leap second insertion has had the strange effect on at leastSome of the reports that the issue is resolved by calling:
Linux versions 3.4.4 (my end) and 3.5-rc4 (Simon's box, Cc) that certain
processes use up all CPU power, because of futexes repeatedly timing
out. This seems to only affect certain processes.
Simon observes - http://s85.org/owXfmLvt - that
Firefox/Thunderbird/Chrome/Java are affected.
As for me, it affects VirtualBox, mysqld and ksoftirqd. The processes
continue to run and respond. Most weird: I can stop-start mysqld and the
issue persists. (I would have expected it to go away because the leap
second event would then be in the past that mysqld does not know about
Is this a kernel issue? glibc?
$ date -s "`date`"
suggests that it might be due to clock_was_set() not being called
after the leap second was added, causing some hrtimer confusion.
Thomas: does that sound about right?
I've got an initial patch to add the clock_was_set() calls where
needed, but so far have not been able to reproduce the issue (tried
firefox and some simpler futex tests). I'll keep trying and hopefully
have something to send out tomorrow.
Again, my apologies for the trouble.
careful with clock_was_set()! See this commit:
In short, clock_was_set() calls on_each_cpu() which is not allowed to be
called in atomic context. Watch out for xtime_lock.