strange crash behaviour with 5.99.5

[Jukka Salmi <j+nbsd%2009.salmi.ch@localhost>]

Hello,

a 5.99.5 i386 system (GENERIC kernel) which ran fine since 2009-01-02
crashed today (somewhere in ehci IIRC) some time (hours?) after having
successfully built a netbsd-5 release and several pkgsrc packages.  I
realised it only when I wanted to log in on the console and noticed the
ddb prompt.  Because I needed the system to be up asap I just wanted to
print a backtrace, force a crash dump and reboot (i.e., `bt' and
`sync').  But the system immediately restarted as soon as I hit `Enter'
after having typed `bt'.  Hmm.

As soon as the system was up again, I noticed that dmesg did show
messages from before the reboot (as expected, since the system in
question usually preserves memory contents across reboots), but I was
unable to find signs of a panic message or similar even though I always
had ddb.tee_msgbuf=1.  And I'm sure there were several lines of green
(kernel) messages before the ddb prompt when I was typing `bt'.  Hmm.
Hmm.

Have there been any recent changes which could explain this behaviour /
"regression"?


Regards, Jukka

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