Kernel panic caused by fork

[Jan Mikkelsen]

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.