On Fri, Oct 03, 2014 at 04:45:53PM +0800, GP Orcullo wrote:
> On Fri, Oct 3, 2014 at 3:20 PM, Gilles Chanteperdrix
> <[email protected]> wrote:
> > On Fri, Oct 03, 2014 at 11:35:33AM +0800, GP Orcullo wrote:
> >> The system managed to dump some error messages.
> >>
> >
> >> [ 407.688809] INFO: rcu_preempt detected stalls on CPUs/tasks: { 3}
> >> (detected by 0, t=12002 jiffies, g=22447, c=22446, q=113448)
> >> [ 407.694560] Task dump for CPU 3:
> >> [ 407.697763] switchtest R running 0 3979 3640 0x00000002
> >> [ 407.704111] [<c0453ddc>] (__schedule+0x1fc/0x5f8) from [<00000010>]
> >> (0x10)
> >> [ 587.714458] INFO: rcu_preempt detected stalls on CPUs/tasks: { 3}
> >> (detected by 2, t=48007 jiffies, g=22447, c=22446, q=443504)
> >> [ 587.720205] Task dump for CPU 3:
> >> [ 587.723407] switchtest R running 0 3979 3640 0x00000002
> >> [ 587.729755] [<c0453ddc>] (__schedule+0x1fc/0x5f8) from [<00000010>]
> >> (0x10)
> >> [ 767.740128] INFO: rcu_preempt detected stalls on CPUs/tasks: { 3}
> >> (detected by 2, t=84012 jiffies, g=22447, c=22446, q=1136198)
> >> [ 767.745964] Task dump for CPU 3:
> >> [ 767.749167] switchtest R running 0 3979 3640 0x00000002
> >> [ 767.755515] [<c0453ddc>] (__schedule+0x1fc/0x5f8) from [<00000010>]
> >> (0x10)
> >> [ 782.763027] ------------[ cut here ]------------
> >> [ 782.763099] WARNING: at include/linux/ipipe_domain.h:212
> >> __ipipe_dispatch_irq+0x35c/0x5a0()
> >> [ 782.770380] Modules linked in: nfsv3 nfsv4 nfsd exportfs nfs_acl
> >> auth_rpcgss nfs lockd sunrpc vfat fat smsc95xx usbnet mii gpio_keys
> >> [ 782.782218] [<c0015624>] (unwind_backtrace+0x0/0xf8) from [<c0026118>]
> >> (warn_slowpath_common+0x4c/0x64)
> >> [ 782.791606] [<c0026118>] (warn_slowpath_common+0x4c/0x64) from
> >> [<c002614c>] (warn_slowpath_null+0x1c/0x24)
> >> [ 782.801232] [<c002614c>] (warn_slowpath_null+0x1c/0x24) from
> >> [<c00886ac>] (__ipipe_dispatch_irq+0x35c/0x5a0)
> >> [ 782.811035] [<c00886ac>] (__ipipe_dispatch_irq+0x35c/0x5a0) from
> >> [<c00200c8>] (combiner_handle_cascade_irq+0x80/0xf4)
> >> [ 782.821620] [<c00200c8>] (combiner_handle_cascade_irq+0x80/0xf4) from
> >> [<c0019110>] (__ipipe_ack_irq+0xc/0x10)
> >
> > This is bad, can I see the code of the "combiner_handle_cascade_irq"
> > function?
> >
>
> Here's the original code:
>
> static DEFINE_SPINLOCK(irq_controller_lock);
>
> ...
>
> static void combiner_handle_cascade_irq(unsigned int irq, struct irq_desc
> *desc)
> {
> struct combiner_chip_data *chip_data = irq_get_handler_data(irq);
> struct irq_chip *chip = irq_get_chip(irq);
> unsigned int cascade_irq, combiner_irq;
> unsigned long status;
>
> chained_irq_enter(chip, desc);
>
> spin_lock(&irq_controller_lock);
> status = __raw_readl(chip_data->base + COMBINER_INT_STATUS);
> spin_unlock(&irq_controller_lock);
> status &= chip_data->irq_mask;
>
> if (status == 0)
> goto out;
>
> combiner_irq = __ffs(status);
>
> cascade_irq = combiner_irq + (chip_data->irq_offset & ~31);
> if (unlikely(cascade_irq >= NR_IRQS))
> do_bad_IRQ(cascade_irq, desc);
> else
> ipipe_handle_demuxed_irq(cascade_irq);
>
> out:
> chained_irq_exit(chip, desc);
> }
>
>
> I've changed the DEFINE_SPINLOCK to IPIPE_DEFINE_SPINLOCK and I got
> the same results.
Same results meaning you still have the warning in ipipe_domain ? Or
still have the lockup?
One of these functions uses local_irq_save/local_irq_restore, one
way to find which is to enable the I-pipe tracer, enable panic
backtrace, and put a BUG_ON(hard_irqs_enabled()) right before the
call to ipipe_handle_demuxed_irq. You probably can not call
do_bad_IRQ from here either, but I do not think this is your
problem, this checks looks a bit redundant: in order to check that
cascade_irq is always less than NR_IRQS, it is sufficient to check
that chip_data->irq_offset & ~31 is less than NR_IRQS - 32, which
can be done only once, and not repeated stupidly for every irq.
--
Gilles.
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