Hi Dave, On 30/08/2016:04:22:30 PM, Dave Young wrote: > Hi, Pratyush > > On 08/16/16 at 08:55am, Pratyush Anand wrote: > > We have observed on few x86 machines with rtc-cmos device that > > hpet_rtc_interrupt() is called just after irq registration and before > > cmos_do_probe() could call hpet_rtc_timer_init(). > > > > So, neither hpet_default_delta nor hpet_t1_cmp is initialized by the time > > interrupt is raised in the given situation, and this results in NMI > > watchdog LOCKUP. > > > > It has only been observed sporadically on kdump secondary kernels. > > > > See the call trace: > > ---<-snip->--- > > 27.913194] Kernel panic - not syncing: Watchdog detected hard LOCKUP on > > cpu 0 > > [ 27.915371] CPU: 0 PID: 1 Comm: swapper/0 Not tainted > > 3.10.0-342.el7.x86_64 #1 > > [ 27.917503] Hardware name: HP ProLiant DL160 Gen8, BIOS J03 02/10/2014 > > [ 27.919455] ffffffff8186a728 0000000059c82488 ffff880034e05af0 > > ffffffff81637bd4 > > [ 27.921870] ffff880034e05b70 ffffffff8163144a 0000000000000010 > > ffff880034e05b80 > > [ 27.924257] ffff880034e05b20 0000000059c82488 0000000000000000 > > 0000000000000000 > > [ 27.926599] Call Trace: > > [ 27.927352] <NMI> [<ffffffff81637bd4>] dump_stack+0x19/0x1b > > [ 27.929080] [<ffffffff8163144a>] panic+0xd8/0x1e7 > > [ 27.930588] [<ffffffff8111d3e0>] ? restart_watchdog_hrtimer+0x50/0x50 > > [ 27.932502] [<ffffffff8111d4a2>] watchdog_overflow_callback+0xc2/0xd0 > > [ 27.934427] [<ffffffff811612c1>] __perf_event_overflow+0xa1/0x250 > > [ 27.936232] [<ffffffff81161d94>] perf_event_overflow+0x14/0x20 > > [ 27.937957] [<ffffffff81032ae8>] intel_pmu_handle_irq+0x1e8/0x470 > > [ 27.939799] [<ffffffff8164164b>] perf_event_nmi_handler+0x2b/0x50 > > [ 27.941649] [<ffffffff81640d99>] nmi_handle.isra.0+0x69/0xb0 > > [ 27.943348] [<ffffffff81640f49>] do_nmi+0x169/0x340 > > [ 27.944802] [<ffffffff816401d3>] end_repeat_nmi+0x1e/0x2e > > [ 27.946424] [<ffffffff81056ee5>] ? hpet_rtc_interrupt+0x85/0x380 > > [ 27.948197] [<ffffffff81056ee5>] ? hpet_rtc_interrupt+0x85/0x380 > > [ 27.949992] [<ffffffff81056ee5>] ? hpet_rtc_interrupt+0x85/0x380 > > [ 27.951816] <<EOE>> <IRQ> [<ffffffff8108f5a3>] ? > > run_timer_softirq+0x43/0x340 > > [ 27.954114] [<ffffffff8111e24e>] handle_irq_event_percpu+0x3e/0x1e0 > > [ 27.955962] [<ffffffff8111e42d>] handle_irq_event+0x3d/0x60 > > [ 27.957635] [<ffffffff811210c7>] handle_edge_irq+0x77/0x130 > > [ 27.959332] [<ffffffff8101704f>] handle_irq+0xbf/0x150 > > [ 27.960949] [<ffffffff8164a86f>] do_IRQ+0x4f/0xf0 > > [ 27.962434] [<ffffffff8163faed>] common_interrupt+0x6d/0x6d > > [ 27.964101] <EOI> [<ffffffff8163f43b>] ? > > _raw_spin_unlock_irqrestore+0x1b/0x40 > > [ 27.966308] [<fffff8111ff07>] __setup_irq+0x2a7/0x570 > > [ 28.067859] [<ffffffff81056e60>] ? hpet_cpuhp_notify+0x140/0x140 > > [ 28.069709] [<ffffffff8112032c>] request_threaded_irq+0xcc/0x170 > > [ 28.071585] [<ffffffff814b24a6>] cmos_do_probe+0x1e6/0x450 > > [ 28.073240] [<ffffffff814b2710>] ? cmos_do_probe+0x450/0x450 > > [ 28.074911] [<ffffffff814b27cb>] cmos_pnp_probe+0xbb/0xc0 > > [ 28.076533] [<ffffffff8139b245>] pnp_device_probe+0x65/0xd0 > > [ 28.078198] [<ffffffff813f8ca7>] driver_probe_device+0x87/0x390 > > [ 28.079971] [<ffffffff813f9083>] __driver_attach+0x93/0xa0 > > [ 28.081660] [<ffffffff813f8ff0>] ? __device_attach+0x40/0x40 > > [ 28.083662] [<ffffffff813f6a13>] bus_for_each_dev+0x73/0xc0 > > [ 28.085370] [<ffffffff813f86fe>] driver_attach+0x1e/0x20 > > [ 28.086974] [<ffffffff813f8250>] bus_add_driver+0x200/0x2d0 > > [ 28.088634] [<ffffffff81ade49a>] ? rtc_sysfs_init+0xe/0xe > > [ 28.090349] [<ffffffff813f9704>] driver_register+0x64/0xf0 > > [ 28.091989] [<ffffffff8139b070>] pnp_register_driver+0x20/0x30 > > [ 28.093707] [<ffffffff81ade4ab>] cmos_init+0x11/0x71 > > ---<-snip->--- > > > > The previous patch split hpet_rtc_timer_init into > > hpet_rtc_timer_counter_init() and hpet_rtc_timer_enable(). > > > > Therefore, this patch moved hpet_rtc_timer_counter_init() before IRQ > > registration, so that we can gracefully handle such spurious interrupts. > > > > We were able to reproduce the problem in maximum 15 trials of kdump > > secondary kernel boot on an hp-dl160gen8 machine without this patch. > > However, more than 35 trials went fine after applying this patch. > > > > Signed-off-by: Pratyush Anand <pan...@redhat.com> > > [dzic...@redhat.com: edited the patch's summary] > > Signed-off-by: Don Zickus <dzic...@redhat.com> > > --- > > drivers/rtc/rtc-cmos.c | 13 ++++++++++++- > > 1 file changed, 12 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/rtc/rtc-cmos.c b/drivers/rtc/rtc-cmos.c > > index 43745cac0141..089d987f2638 100644 > > --- a/drivers/rtc/rtc-cmos.c > > +++ b/drivers/rtc/rtc-cmos.c > > @@ -129,6 +129,16 @@ static inline int hpet_rtc_dropped_irq(void) > > return 0; > > } > > > > +static inline int hpet_rtc_timer_counter_init(void) > > +{ > > + return 0; > > +} > > + > > +static inline int hpet_rtc_timer_enable(void) > > +{ > > + return 0; > > +} > > + > > Can these dummy functions go to /usr/include/linux/hpet.h alont with > the #ifdef etc.
I kept them here because, similar functions like hpet_set_alarm_time() were already there. So, if you suggest that I should have an additional cleanup patch first, which moves existing #ifdef block to inlcude/linux/hpet.h and this patch adds it's inline in linux/hpet.h, then may be I can take that. But not sure if there is something more to be done which will help the MAINTAINER to take it. ~Pratyush > > > static inline int hpet_rtc_timer_init(void) > > { > > return 0; > > @@ -707,6 +717,7 @@ cmos_do_probe(struct device *dev, struct resource > > *ports, int rtc_irq) > > goto cleanup1; > > } > > > > + hpet_rtc_timer_counter_init(); > > if (is_valid_irq(rtc_irq)) { > > irq_handler_t rtc_cmos_int_handler; > > > > @@ -729,7 +740,7 @@ cmos_do_probe(struct device *dev, struct resource > > *ports, int rtc_irq) > > goto cleanup1; > > } > > } > > - hpet_rtc_timer_init(); > > + hpet_rtc_timer_enable(); > > > > /* export at least the first block of NVRAM */ > > nvram.size = address_space - NVRAM_OFFSET; > > -- > > 2.5.5 > > > > Thanks > Dave -- You received this message because you are subscribed to "rtc-linux". Membership options at http://groups.google.com/group/rtc-linux . Please read http://groups.google.com/group/rtc-linux/web/checklist before submitting a driver. --- You received this message because you are subscribed to the Google Groups "rtc-linux" group. To unsubscribe from this group and stop receiving emails from it, send an email to rtc-linux+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.