[Jackit-devel] Re: [linux-audio-dev] Re: [Jackit-devel]2.4.20Â + lowlat +preempt + alsa + jack = dead computer

[Fernando Pablo Lopez-Lezcano]

On Sat, 2003-01-04 at 01:49, Andrew Morton wrote:
> Fernando Pablo Lopez-Lezcano wrote:
> > 4)
> > schedule +1ab
> > sleep_on +45
> > bread +20
> > __mark_inode_dirty +d9
> > pipe_write +1b9
> > poll_freewait +44
> > sys_write +9f
> > system_call +33
> > 
> > So the system seems to be stuck in __mark_inode_dirty, whatever that is.
> 
> No, that's just stack gunk.
> 
> There's no sign of a deadlock or a livelock in these traces.  It just
> looks like these tasks are asleep and not waking up.
> 
> > Each time I break into the debugger I see one of the jack related
> > processes as the current process. No other processes, so I assume the
> > SCHED_FIFO ring is still running but everything else is being blocked by
> > the mark_inode_dirty call.
> 
> Why do we not believe that this is an application bug? 

Last time I tried, this did not happen in 2.4.19 so I assumed it was a
problem in 2.4.20 (boot into 2.4.19, no problems, boot into 2.4.20,
lockups, same everything else). Other users have reported this as well
(in 2.4.20 only AFAIK). Other users are using the exact same versions of
jack and associated software under a 2.4.19 kernel intensively (through
Planet CCRMA) and have not reported lockups. 

It could also be that 2.4.20 makes a race condition inside jack more
likely, and exposes a bug in jack. I'll test again in 2.4.19 just to
make sure I'm still seeing the same thing.

Thanks for the help, I'll try out your suggestions and report back. 
-- Fernando