Re: 2.6.8-rc1-mm1 "Badness in schedule" on ppc32

[Tom Rini <trini@kernel.crashing.org>]

On Thu, Jul 15, 2004 at 09:08:27PM +0200, Mikael Pettersson wrote:

> On Thu, 15 Jul 2004 02:00:01 +0200 (MEST), Mikael Pettersson wrote:
> >On 2004-07-14 22:01:50, Tom Rini wrote:
> >>On Fri, Jul 09, 2004 at 02:11:03PM -0700, Andrew Morton wrote:
> >>
> >>> 
> >>> jhf@rivenstone.net (Joseph Fannin) wrote:
> >>> > 
> >>> > On Thu, Jul 08, 2004 at 11:50:25PM -0700, Andrew Morton wrote:
> >>> > > 
> >>> > > ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.7/2.6.7-mm7/
> >>> > 
> >>> > > +detect-too-early-schedule-attempts.patch
> >>> > > 
> >>> > > Catch attempts to call the scheduler before it is ready to go.
> >>> > 
> >>> > With this patch, my Powermac (ppc32) spews 711 (I think)
> >>> > warning messages during bootup.
> >>> 
> >>> hm, OK.  It could be that the debug patch is a bit too aggressive, or that
> >>> ppc got lucky and happens to always be in state TASK_RUNNING when these
> >>> calls to schedule() occur.
> >>> 
> >>> Maybe this task incorrectly has _TIF_NEED_RESCHED set?
> >>> 
> >>> Anyway, ppc guys: please take a look at the results from
> >>> ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.7/2.6.7-mm7/broken \
> >>> -out/detect-too-early-schedule-attempts.patch and check that the kernel really \
> >>> should be calling schedule() at this time and place, let us know?
> >>
> >>Now that kallsyms data is OK, I took a quick look.. and all of this
> >>comes from generic code, at least on the machine I tried.  So if the
> >>code shouldn't be calling schedule() then, it's a more generic problem..
> >>
> >>... or I'm not following.
> >
> >On my ppc32 (G3 PowerMac) 2.6.8-rc1-mm1 throws a large number of
> >"Badness in schedule" during boot. Below are the ones I managed
> >to capture: they contain both generic traces, and traces involving
> >Mac-only drivers.
> >
> >Some of the traces involve the PDC202XX_NEW driver; I'll move that
> >card into an x86 PC tomorrow to see if the traces reappear or not;
> >if they don't then it does look like a PPC32-specific problem.
> 
> Tried that now but I've been unable to trigger any
> "Badness in schedule" messages on the x86 box.
> Looks like PPC32 has a problem in -mm.

On x86, could you force the PDC202XX_NEW to dump_stack in the function
in question?  Perhaps there's a calling order issue on ppc.  Thanks.

-- 
Tom Rini
http://gate.crashing.org/~trini/