Re: calcru-triggered panic?

From: John Birrell <jb_at_what-creek.com> Date: Wed, 29 Nov 2006 22:32:21 +0000 · This archive was generated by hypermail 2.4.0 : Wed May 19 2021 - 11:39:03 UTC

On Wed, Nov 29, 2006 at 12:04:03PM -0500, John Baldwin wrote:
> On Monday 20 November 2006 16:38, Rene Ladan wrote:
> > Hi,
> > 
> > I got the attached panic on CURRENT 2006-11-17.
> > 
> > It was preceded by a lot of 'calcru' messages.
> 
> The calcru messages you can ignore.
> 
> This is the real problem:
> 
> panic: blockable sleep lock (sleep mutex) tty 
> _at_ /usr/src-current/sys/kern/kern_event.c:1670
> 
> This panic is due to the recent changes to printf to try to buffer the printf 
> output.  It now runs cnputc() under a critical section and syscons(4) tries 
> to do a ttwakeup() which invokes KNOTE() and tries to lock a regular mutex 
> while inside the critical section.  I'm not sure how best to fix this.

I would like to go back to using a printf buffer on the stack
(like I had in my original implementation). The downside of
doing that is that it places more stress on the stack and for
things like cam, that is an issue, so I am told.

--
John Birrell