Big problems with 7.1 locking up :-(

[Robert Watson]

On Mon, 12 Jan 2009, Garance A Drosihn wrote:

> He is not eager to do a whole lot of experiments to track down the problem, 
> since this is happening on busy production machines and he can't afford to 
> have a lot of downtime on them (especially now that the semester at RPI has 
> started up).  The systems have some large (2 TB) filesystems on them, and 
> the lockups occur in high disk-I/O situations. He's seeing the problem on 
> one system which is a dual CPU quad-core xeon, and another which is a 64 bit 
> P4 with hyperthreading.  The one thing in common between the two setups is 
> that the boot drives + a 3ware controller (with its array of RAID disks) is 
> moved from one machine to the other one:

I think playing the combinatorics game on compile-time flags, kernel features, 
etc, is probably not the best way to go about debugging this.  Instead, I'd 
debug this as a kernel hang by breaking into the debugger once it occurs, if 
possible, and ideally on a serial console.  Often times hangs can be debugged 
looking solely at DDB output, or if possible, a crash dump.

Robert N M Watson
Computer Laboratory
University of Cambridge