[ntp:questions] Ntpd in uninterruptible sleep?

Chuck Swiger cswiger at mac.com
Mon Oct 24 21:33:07 UTC 2011


On Oct 24, 2011, at 2:26 PM, A C wrote:
>> If ntpd crashes, you should get a coredump which you can debug (assuming you've setup the coredumpsize limit to permit this) and perhaps a syslog message about a SIGSEGV, SIGBUS, or whatever.
> 
> Not if it locks the system up entirely (as in I couldn't even break out of the kernel) which is what had been happening.  Turning off the priority on ntpd (eliminating the use of the -N flag) seems to avoid the system lock up issue but doesn't eliminate the ntpd lockup.

That sounds somewhat like an OS bug, where running at very high priority might livelock the system and prevent it from servicing network traffic or interrupts.  You haven't mentioned which version of NetBSD you are running; it's possible that it's a known issue which has since been fixed.

Or it could just be something else in the H/W getting flakey...

> The process just sat there yesterday not doing anything and bogging the machine down.  The process itself doesn't die, there's no core to dump (yet), it just sits and sits and sits...

This case should be debuggable-- you can to use gdb to attach to the process and see where it is, or fire off ptrace against it.

Regards,
-- 
-Chuck



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