On Wed, 21 Jul 2010, gowrishankar wrote:
> On Wednesday 21 July 2010 03:56 AM, Jeremy Brown wrote:
> > We're trying to get a PREEMPT_RT kernel running on a BeagleBoard C4
> > (OMAP3 Arm architecture). We're using kernel version 2.6.33, with
> >
> 2.6.33 ! not 2.6.33.6 ???
> > patches from
> > patch-2.6.33.6-rt26.gz
> >
> > On boot, we start seeing messages of this form:
> >
> > ----
> > [ 4528.227294] BUG: sleeping function called from invalid context at
> > kernel/rtmutex.c:684
> > [ 4528.227294] pcnt: 1 0 in_atomic(): 1, irqs_disabled(): 128, pid:
> > 223, name: modprobe
> > [ 4528.227355] [<c0044490>] (unwind_backtrace+0x0/0xe8) from
> > [<c04cb4e4>] (rt_spin_lock+0x30/0x5c)
> > [ 4528.227386] [<c04cb4e4>] (rt_spin_lock+0x30/0x5c) from [<c032e3b0>]
> > (twl4030_sih_set_type+0x3c/0xac)
> >
> sleeping spin lock is called while preempt/interrupt is disabled.
>
> Can you try the below patch ?
>
> Signed-off-by: Gowrishankar <gowrishankar.m@xxxxxxxxxx>
>
> Index: linux-2.6.33.6-rt26/drivers/mfd/twl4030-irq.c
> ===================================================================
> --- linux-2.6.33.6-rt26.orig/drivers/mfd/twl4030-irq.c 2010-07-21
> 12:40:42.000000000 +0530
> +++ linux-2.6.33.6-rt26/drivers/mfd/twl4030-irq.c 2010-07-21
> 12:41:16.000000000 +0530
> @@ -633,14 +633,14 @@
> if (trigger & ~(IRQ_TYPE_EDGE_FALLING | IRQ_TYPE_EDGE_RISING))
> return -EINVAL;
>
> - spin_lock_irqsave(&sih_agent_lock, flags);
> + raw_spin_lock_irqsave(&sih_agent_lock, flags);
> if ((desc->status & IRQ_TYPE_SENSE_MASK) != trigger) {
> desc->status &= ~IRQ_TYPE_SENSE_MASK;
> desc->status |= trigger;
> sih->edge_change |= BIT(irq - sih->irq_base);
> queue_work(wq, &sih->edge_work);
> }
> - spin_unlock_irqrestore(&sih_agent_lock, flags);
> + raw_spin_unlock_irqrestore(&sih_agent_lock, flags);
Nope, that's not going to fly. First it does not compile and second
you trigger the same problem in queue_work() which is called inside
that section. That needs a bit more work, will have a look. (/me
mentions, that todo list is already overly full, so do not expect
wonders).
Thanks,
tglx
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