Subject: Re: 7GB memtest causes hard system hang.
To: Hubert Feyrer <hubert@feyrer.de>
From: Thor Lancelot Simon <tls@rek.tjls.com>
List: port-amd64
Date: 01/13/2006 14:02:22
On Fri, Jan 13, 2006 at 11:47:55AM +0100, Hubert Feyrer wrote:
> On Thu, 12 Jan 2006, Thor Lancelot Simon wrote:
> >kernel.  Because of the memorylocked issue, to run a 7GB memtest I have
> >to configure a few hundred megabytes of swap.
> >
> >A 4GB memtest runs fine; so does 5; I didn't try 6.
> >
> >However, a 7GB memtest gives a quick and irretrievable system hang.  The
> >system appears unable even to drop to DDB.
> >
> >I'm really not even sure how to start debugging this.
> 
> A good first step is describing how to reproduce the problem.

Hubert,

The message you quoted _most of_ described exactly how to reproduce the
problem.  Boot a 3.0 GENERIC.MP kernel on a dual-Opteron system with 8GB
of RAM.  Next, unlimit datasize, memoryuse, and memorylocked.  Next,
run "memtester" from pkgsrc -- I see I accidentally called it "memtest",
but since that's the only memory tester we have that runs under NetBSD
and it's also the one everyone uses, I hardly think that's too hard to
figure out -- specifying a 7GB test size; it's the only command line option
memtester takes, and it's mandatory.  Next, watch your system hang so hard
that you can't get it to drop to DDB.

The hang is so simple to reproduce that it only requires a few words, some
of which you snipped when quoting my message.  Why are you being a snot?

Thor