Kernel panic caused by fork
Jan Mikkelsen
janm-freebsd-hackers at transactionware.com
Tue Sep 8 09:19:57 UTC 2009
Hi,
On 07/09/2009, at 8:59 PM, Ivan Radovanovic wrote:
...
> After running this program I got kernel panic with message
> "get_pv_entry: increase vm.pmap.shpgperproc"
> IMHO it is not very good idea to bring entire system down if one
> process misbehaves in this way, it is maybe much better to kill
> offending process and to send this message to system log. I am not
> sure whether the panic is actually caused by process forking forever
> or when the system tries to create new process when maxproc limit is
> already reached (since system is only printing warning message that
> maxproc limit is reached and it only panics when I try to start new
> process (like ps)).
A quick observation: This is not "one process misbehaving", it is a
large number of processes misbehaving. From an administrative point
of view, I think the response is "call setrlimit(RLIMIT_NPROC, ...)",
otherwise the expected behaviour is for your machine to stop making
forward progress.
Having said that, I agree that panics are bad and it would be nice if
fork() returned EAGAIN, again and again and again. Or perhaps the
machine should just panic ...
Regards,
Jan.
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