Am 25.10.2010 21:40, Jan Kiszka wrote: > Am 25.10.2010 21:03, Peter Pastor wrote: >> Hey Jan, >> >> I did not apply any ubuntu patch for kernel 2.6.35 (since I do not have >> one). Also, good to know that I should not use xenomai patches together >> with ubuntu patches. >> >> Anyway, the problem occurred as well with the kernel 2.6.35 (see attached >> dmesg_bad_2.6.35) >> I also attached the config. >> > > ... > >> [ 5751.714643] irq 16: nobody cared (try booting with the "irqpoll" option) >> [ 5751.714649] Pid: 0, comm: swapper Tainted: P >> 2.6.35-ipipe-2.5.4-slim #2 >> [ 5751.714653] Call Trace: >> [ 5751.714655] <IRQ> [<ffffffff8108bb56>] __report_bad_irq+0x26/0xa0 >> [ 5751.714668] [<ffffffff8108bd5c>] note_interrupt+0x18c/0x1d0 >> [ 5751.714672] [<ffffffff8108c77d>] handle_fasteoi_irq+0xcd/0x100 >> [ 5751.714677] [<ffffffff8100656d>] handle_irq+0x1d/0x30 >> [ 5751.714681] [<ffffffff81005a40>] do_IRQ+0x70/0x100 >> [ 5751.714685] [<ffffffff81092147>] __ipipe_sync_stage+0x207/0x20d >> [ 5751.714689] [<ffffffff810059d0>] ? do_IRQ+0x0/0x100 >> [ 5751.714692] [<ffffffff8109214d>] ? __xirq_end+0x0/0x9c >> [ 5751.714696] [<ffffffff810059d0>] ? do_IRQ+0x0/0x100 >> [ 5751.714700] [<ffffffff810926a3>] __ipipe_walk_pipeline+0x113/0x120 >> [ 5751.714706] [<ffffffff81024414>] __ipipe_handle_irq+0x124/0x310 >> [ 5751.714708] [<ffffffff8108bf10>] ? __ipipe_ack_fasteoi_irq+0x0/0x10 >> [ 5751.714712] [<ffffffff814f78d3>] common_interrupt+0x13/0x2c >> [ 5751.714713] <EOI> [<ffffffff810249d6>] ? __ipipe_halt_root+0x26/0x40 >> [ 5751.714718] [<ffffffff81061191>] ? atomic_notifier_call_chain+0x11/0x20 >> [ 5751.714722] [<ffffffff8100cbd5>] default_idle+0x45/0x50 >> [ 5751.714725] [<ffffffff8100198a>] cpu_idle+0x7a/0xd0 >> [ 5751.714728] [<ffffffff814f14a1>] start_secondary+0x1c1/0x1c5 >> [ 5751.714730] handlers: >> [ 5751.714730] [<ffffffff8136ed60>] (usb_hcd_irq+0x0/0xb0) >> [ 5751.714735] [<ffffffffa00bac30>] (mpt_interrupt+0x0/0xa00 [mptbase]) >> [ 5751.714747] Disabling IRQ #16 > > I'm not yet sure, but a first thought: We have a shared fasteoi IRQ > here, and we are on SMP. Compared to vanilla, the fasteoi flow of ipipe > looks so much different to me ATM that I tend to believe two cores end > up having this IRQ queued at the same time. One runs first and handles > all triggers, the second bails out like above. > > Philippe, we _end_ fasteoi in the ipipe ack path. Do we mask them prior > to this? What prevents a second IRQ arriving after this early eoi? >
Slowly getting more confident in this theory. Peter, you could increase the confidence further by binding the IRQ #16 to a single core (e.g. echo 1 > /proc/irq/16/smp_affinity, make sure to stop irqbalance first in case it's running). Moreover, edge handling looks similarly broken: We ack the IRQ early, there is no further masking, but we do not block delivery /wrt other cores - in contrast to Linux which has IRQ_INPROGRESS, checked and set atomically along with the ack (if I-pipe is off). And this issue should not only affect Linux, Xenomai may get equally unhappy if ever faced with a bunch of shared edge RT-IRQs on a SMP box. Uff. Jan
signature.asc
Description: OpenPGP digital signature
_______________________________________________ Xenomai-help mailing list [email protected] https://mail.gna.org/listinfo/xenomai-help
