Using read-only NULLFS leads to panic. gdb output included,easy toreproduce.

[Marc G. Fournier]

Just curious, but why use nullfs for this?  On our boxes, I do a:

mount_unionfs -b /usr/ports /mnt/usr/ports

and haven't had any problems ... curious as to what nullfs gives over
unionfs for ports ...

On Tue, 2 Mar 2004, James Read wrote:

> Quickly forgot to mention this occured on 4.9 RELEASE and also when I
> upgraded to 4.9-STABLE #0: Sun Feb 15.
>
> Kernel is GENERIC with just IPFW + DUMMYNET added in.
>
> Regards,
>
> James.
>
>
>
>
> ----- Original Message -----
> From: "James Read" <james at physicalsegment.com>
> To: "Pawe³ Ma³achowski" <pawmal-posting at freebsd.lublin.pl>
> Cc: <stable at freebsd.org>
> Sent: Wednesday, March 03, 2004 10:48 PM
> Subject: Re: Using read-only NULLFS leads to panic. gdb output included,easy
> toreproduce.
>
>
> > > find /usr/ports -type f -perm -u+s &
> > > find /usr/ports -type f -perm -u+s &
> > > ...
> > > find /mnt/1 -type f -perm -u+s &
> > > find /mnt/1 -type f -perm -u+s &
> > > ...
> > > find /mnt/2 -type f -perm -u+s &
> > > find /mnt/2 -type f -perm -u+s &
> > > ...
> > >
> > > (Machine C crashed after few minutes).
> >
> >
> > All I can say is that I've had this happen to me before. 'Me too'
> >
> > The ports were mounted in exact the same way, but with rw instead of ro.
> >
> > Also a few jails were running at the time, infact 3 were. All had
> /usr/ports
> > mount_null'ed inside there jail.
> >
> > After running find from the usual periodic scripts it brought the machine
> > down every time it ran that script.
> >
> > What I did to stop the box from panicing all the time at that one
> particular
> > place, was just to disable the script that does the 'find' / locate. Off
> the
> > top of my head I think it was /etc/periodic/weekly/310.locate. Once this
> was
> > disabled (from inside and outside the jails), I didnt get any more panics
> > from 'find'.
> >
> > Granted this isnt a fix, but it did save me from panic hell every week.
> >
> > If there is a better way / another way to 'mount_null' /usr/ports (or any
> > other mount point for that matter) to other places in/on the filesystem,
> by
> > using NFS or other such things, then speak up! I don't like getting panics
> > more then anyone else does ;>
> >
> > Regards,
> >
> > James.
> >
> >
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----
Marc G. Fournier           Hub.Org Networking Services (http://www.hub.org)
Email: scrappy at hub.org           Yahoo!: yscrappy              ICQ: 7615664