Re: setting DDB_COMMANDONENTER="bt" by default

[Valery Ushakov <uwe%stderr.spb.ru@localhost>]

On Thu, Feb 15, 2018 at 02:11:07 +0000, Sevan Janiyan wrote:

> On 02/15/18 01:23, Valery Ushakov wrote:
> > As someone has already mentioned upthread, because printing a
> > backtrace might cause another panic, so the default was selected to be
> > on the safe(r) side.  At least that's what I recall.
> 
> On 02/15/18 01:33, Paul Goyette wrote:
> > Yes, that matches my recall as well.
> 
> Ah, ok, so leave this to rest? (is it worth testing in -current to see
> how things go?)

Well, "testing" here would be to throw random garbage in the stack for
"bt" to choke on (and that garbage might also need to point to just
the right other data).  You might be able to script this with
something like vbox snapshots I guess, by snapshotting a VM when it's
in ddb and then fuzzing the kernel stack before resuming it (I don't
remember if vbox vm debugger is scriptable, you might also need to
hack it a bit to be).

-uwe