Subject: Re: ok to remove DDB_ONPANIC=1 from XEN{0,U}?
To: Jonathan A. Kollasch <jakllsch@kollasch.net>
From: Greg Troxel <gdt@ir.bbn.com>
List: current-users
Date: 12/01/2005 13:15:02
"Jonathan A. Kollasch" <jakllsch@kollasch.net> writes:
> On Thu, Dec 01, 2005 at 11:30:28AM -0500, Greg Troxel wrote to port-xen:
> > After splitting GENERIC.local/INSTALL.local, I'm going over my configs
> > and putting what I want (IPSEC, stf(4)) in GENERIC.local. I found
> > that I also had disabled DDB_ONPANIC, and think this doesn't belong in
> > XEN's GENERIC equivalent since it is unsuitable for production. Any
> > objections to committing the following?
>
> While it may be unsuitable for production, there is precedence for
> having DDB_ONPANIC set in GENERIC. All archs I know about (alpha, i386,
> macppc) have it set by default. Not having it set makes postmortem
> debugging nearly impossible. IMHO this should be unset by sysctl after
> boot if desired.
Thanks for pointing that out - I was confused. Having "options DDB"
leads to ddb-on-panic unless one has
options DDB_ONPANIC=0
because src/sys/ddb/ddb_variables.c has
/*
* If this is non-zero, the DDB will be entered when the system
* panics. Initialize it so that it's patchable.
*/
#ifndef DDB_ONPANIC
#define DDB_ONPANIC 1
#endif
int db_onpanic = DDB_ONPANIC;
Currently pmax GENERIC sets DDB_ONPANIC to 0, but the rest of the
GENERICs don't. I'd like to have the default be not to enter DDB on
panic because rebooting is a better response for people who haven't
thought about this.
But, I've set ddb.onpanic=0 in /etc/sysctl.conf on most of my
machines.
Still, I think XEN* should match GENERIC unless there's a reason, in
which case there should be a comment.
--
Greg Troxel <gdt@ir.bbn.com>