[ntp:questions] Ntpd in uninterruptible sleep?
agcarver+ntp at acarver.net
Thu Nov 10 07:39:29 UTC 2011
On 11/9/2011 20:32, Dave Hart wrote:
> On Thu, Nov 10, 2011 at 04:21, A C<agcarver+ntp at acarver.net> wrote:
>> As expected, it crashed again. The interesting thing is that the constant
>> output from -D2 stopped in its tracks. Nothing in the output shows anything
>> out of the ordinary. It just halts completely.
> That's progress, and tells me a lot. We need to see where ntpd is
> stuck, I think that means either attaching gdb to the hung ntpd, or
> starting it again under gdb and breaking into gdb once it hangs. I'm
> relatively weak on gdb, but I believe if it's started under gdb, ^C
> will break into a gdb> prompt.
> Once in, use "bt" to get a stack trace that hopefully goes back to
> ntpdmain (that is, is hopefully on the correct ntpd thread, and not
> any secondary or gdb-created thread).
I'll restart it under gdb and see what happens when it hangs again.
I did have a question about the debug data out of -D2. What does the
"head" parameter indicate in a poll_update? I notice that most of the
time head is zero but once in a while it's something else. The log of
the debug data shows it's gone over 500 a couple times.
This one is zero, I lost the bigger one which
> poll_update: at 3966 127.127.22.1 poll 4 burst 0 retry 0 head 0 early 2 next 16
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