Re: Lemote YeeLoong (LOONGSON) freezes during nightly maintenance operations

["John D. Baker" <jdbaker%mylinuxisp.com@localhost>]

On Mon, 2 Jan 2017, David Holland wrote:

> On Tue, Dec 06, 2016 at 08:03:08AM -0600, John D. Baker wrote:
> > In the past, it would provoke a panic and leave the system sitting at
> > the debugger.  Now it just freezes, completely unresponsive except for
> > the power button.
> 
> Do you remember what the panic was?

I recall logging this error to the mailing list some time ago and just
now found where it is:

  http://mail-index.netbsd.org/port-evbmips/2016/10/06/msg000295.html

I would routinely see that error in the past although it was not guaranteed
to happen (some nights it would complete the file system scan without
problems).

> also, something that might be useful to test is to create a directory
> tree the same size as the ext2fs ones using some other fs (e.g. tmpfs)
> and see what happens if the find / scans that.
> 
> (same size == same tree depth and number of names/inodes)

Hmm.  That might be possible.  The big ext2fs filesystem holds complete
trees for pkgsrc-HEAD and -current src, xsrc as well as OpenBSD src,
xenocara, and ports, plus snapshot tar files.  Also home directories
for local users, intended to be shared between all OSes on the machine.

So, traverse the file system and clone it by making directories and
'touch' dummy files somewhere else?  I'd have to do that under penguin-OS,
tar up the result and plop it onto a tmpfs (or ffs).

> If that dies the problem is probably somewhere in vfs or uvm... if it
> doesn't, it might still be the block driver rather than ext2fs.
> 
> If you don't object to triggering the problem on purpose a few times,
> it might also be useful to try LOCKDEBUG.

I already run a kernel with DEBUG and LOCKDEBUG.  They have so far
remained silent when the machine hangs.

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