"panic: malloc(M_WAITOK) in interrupt context" while in DDB
Brian Fundakowski Feldman
green at FreeBSD.org
Sun Jul 11 19:59:50 PDT 2004
On Sun, Jul 11, 2004 at 08:16:37PM -0400, Robert Watson wrote:
> Got the following rather drawn out stack trace while working with DDB on a
> panic earlier this afternoon. I got a good three panics/traps:
> (1) Breaking to DDB using the serial console to evaluate a hang. (fine)
> (2) Calling panic from DDB to get a dump, which generated a trap because
> it tried to sync(). (Remind me: why do we do that?)
> (3) Getting a panic because I called panic from that session of DDB
> because KDB tried to perform an orderly shutdown, resulting in GEOM
> panicking on trying to generate safe shutdown events by mallocing.
> It sounds like we should really turn off trying to sync() in panic(). It
> sounds like we also should also have a better way of having module
> shutdown take place from the debugger.
I think I've been trying to get people to accept that it's a bad idea
for years now. Any machine I touch just gets debug.sync_on_panic=0 in
its /etc/sysctl.conf immediately.
Brian Fundakowski Feldman \'[ FreeBSD ]''''''''''\
<> green at FreeBSD.org \ The Power to Serve! \
Opinions expressed are my own. \,,,,,,,,,,,,,,,,,,,,,,\
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