9.3-RELEASE still instapanics on multi-mps(4) servers

[John-Mark Gurney]

Garrett Wollman wrote this message on Wed, Aug 06, 2014 at 15:46 -0400:
> Remember about six months ago when I tested 9-stable on one of my big
> NFS servers, and had it panic in the middle of the USB probe, but
> ultimately bisected the problem to an update to the mps(4) driver?  I
> had to stop investigating and get the server working (which I did, by
> installing 9.2 instead of something newer and presumably faster).  I'm
> at the point now where I'd like to upgrade my file servers to 9.3, and
> I can't, because of this issue, so it's time to start tracking down
> the bug again.
> 
> I have two test servers now.  9.3 works just fine on one of them, and
> panics on the other.  The one it works on is slightly older, and has
> an mpt(4) controller for the boot drives, as opposed to the system
> where the panic happens, which is mps(4)-only.  Both systems have two
> SAS2116 controllers for external drives; the ones on the working
> system have drives attached, and the ones on the non-working system
> are not connected to anything (and in fact disabled in the BIOS for
> now).
> 
> Any experts want to suggest where to start (besides, obviously,
> attaching a serial console, which I haven't done yet)?  I saw one
> change in the svn logs for 9.3 prior to the release which looked like
> it might be a relevant fix, but it clearly hasn't improved anything
> for my servers.

One thing you could do is turn on DEBUG_MEMGUARD and DEBUG_REDZONE
and see if they trigger...

-- 
  John-Mark Gurney				Voice: +1 415 225 5579

     "All that I will do, has been done, All that I have, has not."