Re: OMAP34xx

[Luciano Coelho <coelho@ti.com>]

Hi Kevin,

On Wed, 2012-02-15 at 16:13 -0800, Kevin Hilman wrote: 
> On 02/15/2012 03:54 PM, Kevin Hilman wrote:
> > Luciano Coelho<coelho@ti.com>  writes:
> >
> > [...]
> >
> >> I just tried this on my Panda and I keep getting this kind of BUGs.  It
> >> spams my console so much that is pretty much unusable:
> >>
> >> [  336.172302] BUG: sleeping function called from invalid context at include/linux/freezer.h:46
> >> [  336.181213] in_atomic(): 0, irqs_disabled(): 128, pid: 1618, name: ntpd
> >> [  336.181213] INFO: lockdep is turned off.
> >> [  336.181213] irq event stamp: 0
> >> [  336.181213] hardirqs last  enabled at (0): [<   (null)>]   (null)
> >> [  336.201660] hardirqs last disabled at (0): [<c0042314>] copy_process+0x3ec/0x105c
> >> [  336.209625] softirqs last  enabled at (0): [<c0042314>] copy_process+0x3ec/0x105c
> >> [  336.217498] softirqs last disabled at (0): [<   (null)>]   (null)
> >> [  336.217498] [<c001e1e4>] (unwind_backtrace+0x0/0x148) from [<c0502c24>] (dump_stack+0x20/0x24)
> >> [  336.232879] [<c0502c24>] (dump_stack+0x20/0x24) from [<c0077998>] (__might_sleep+0x130/0x134)
> >> [  336.232879] [<c0077998>] (__might_sleep+0x130/0x134) from [<c0018998>] (do_signal+0x54/0x600)
> >> [  336.250793] [<c0018998>] (do_signal+0x54/0x600) from [<c0018fa4>] (do_notify_resume+0x60/0x6c)
> >> [  336.250793] [<c0018fa4>] (do_notify_resume+0x60/0x6c) from [<c00154e4>] (work_pending+0x24/0x28)
> >>
> >> I have also seen this in 3.3-rc3 (both on Panda (OMAP4460) and on Blaze
> >> (OMAP4430) boards) and I was hoping your tree would have the fix for it,
> >> but it doesn't. :( The device boots and seems to work otherwise, but
> >> this is annoying and looks shaky.
> >>
> >> I saw something related to this in another thread from a few months ago,
> >> and one patch proposal by Russell, but I didn't find any conclusion or
> >> any related patch queued up for upstream.
> >>
> >> Is there any solution for this? I use a tuned .config (attached) and not
> >> the one generated by omap2plus_defconfig (which I didn't try as
> >> vanilla).
> >
> > I see the same thing with your ~/.config, but I don't think this is OMAP
> > specific.  I suspect this will happen on any ARM platform that  has
> > CONFIG_DEBUG_ATOMIC_SLEEP=y.

Right.  I always use CONFIG_DEBUG_ATOMIC_SLEEP.  And yes, according to
what I had seen, this was an ARM issue not only OMAP.


> > It appears to be a problem with the recently added audit support for
> > ARM, since reverting the commit below makes this BUG go away.
> 
> False alarm.  reverting the audit commit didn't make the problem go 
> away.  It was gone only because I also disabled 
> CONFIG_DEBUG_ATOMIC_SLEEP.  :/
> 
> To debug this further, you might bisect it back to v3.2 because the 
> problem isn't there in v3.2

When I was looking a bit further, I found this patch: a0acae0e "freezer:
unexport refrigerator() and update try_to_freeze() slightly", which
seems to be the one introducing the bug.  It's quite far back and quite
large, so reverting it is not that easy.

I may try to do some bisecting later today, but I'm not sure I'll have
the time.

-- 
Cheers,
Luca.