Re: [nohz] WARNING: CPU: 0 PID: 0 at arch/x86/kernel/cpu/common.c:1430 warn_pre_alternatives()

From: Fengguang Wu
Date: Thu Sep 11 2014 - 17:18:13 EST

Hi Frederic,

On Thu, Sep 11, 2014 at 05:53:19PM +0200, Frederic Weisbecker wrote:
> Hi,
>
> On Thu, Sep 11, 2014 at 03:17:04PM +0800, Fengguang Wu wrote:
> > Greetings,
> >
> > 0day kernel testing robot got the below dmesg and the first bad commit is
> >
> > git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git nohz/fixes-v2
> >
> > commit 664c05b9ab2dd92aad807bd7f9aa273955949abe
> > Author: Frederic Weisbecker <fweisbec@xxxxxxxxx>
> > AuthorDate: Sun Aug 17 22:02:55 2014 +0200
> > Commit: Frederic Weisbecker <fweisbec@xxxxxxxxx>
> > CommitDate: Wed Sep 10 18:52:45 2014 +0200
> >
> > nohz: Consolidate nohz full init code
> >
> > The supports for CONFIG_NO_HZ_FULL_ALL=y and the nohz_full= kernel
> > parameter both have their own way to do the same thing: allocate
> > full dynticks cpumasks, fill them and initialize some state variables.
> >
> > Lets consolidate that all in the same place.
> >
> > While at it, convert some regular printk message to warnings when
> > fundamental allocations fail.
> >
> > Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> > Cc: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
> > Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> > Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> > Signed-off-by: Frederic Weisbecker <fweisbec@xxxxxxxxx>
> >
> > +-----------------------------------------------------------------+------------+------------+------------+
> > | | ed1fb75de3 | 664c05b9ab | dd99eb9cdf |
> > +-----------------------------------------------------------------+------------+------------+------------+
> > | boot_successes | 60 | 0 | 0 |
> > | boot_failures | 0 | 20 | 23 |
>
> So you tested ed1fb75de3 and 664c05b9ab with the same config that is in attachement, right?

Yes.

> I can't find what dd99eb9cdf refers to though.

It's an internal merge-and-test branch head.

> One more thing below:
>
> > | WARNING:at_arch/x86/kernel/cpu/common.c:warn_pre_alternatives() | 0 | 20 | 22 |
> > | BUG:kernel_boot_hang | 0 | 20 | 22 |
> > | backtrace:setup_default_timer_irq | 0 | 20 | 22 |
> > | backtrace:hpet_time_init | 0 | 20 | 22 |
> > | backtrace:x86_late_time_init | 0 | 20 | 22 |
> > | WARNING:CPU:PID:at/kbuild/ | 0 | 1 | |
> > | WARNING:CPU:PID:at_arch/x86/k | 0 | 1 | |
> > | WARNING:CPU:PID:at_arch/x86/kernel/cpu/common.c:warn_pre_al | 0 | 0 | 1 |
> > | BUG:kernel_boot_crashed | 0 | 0 | 1 |
> > +-----------------------------------------------------------------+------------+------------+------------+
> >
> > [ 0.000000] ----------------------------------------------------
> > [ 0.000000] hpet clockevent registered
> > [ 0.000000] ------------[ cut here ]------------
> > [ 0.000000] WARNING: CPU: 0 PID: 0 at arch/x86/kernel/cpu/common.c:1430 warn_pre_alternatives+0x1e/0x20()
> > [ 0.000000] You're using static_cpu_has before alternatives have run!
> > [ 0.000000] Modules linked in:
> > [ 0.000000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.17.0-rc3-00007-g664c05b #840
> > [ 0.000000] 0000000000000009 ffff880012603d80 ffffffff89dfe8c6 ffff880012603dc8
> > [ 0.000000] ffff880012603db8 ffffffff89a81df3 ffffffff8a414580 0000000000000000
> > [ 0.000000] 0000000000000000 0000000000000000 0000000000000000 ffff880012603e18
> > [ 0.000000] Call Trace:
> > [ 0.000000] <IRQ> [<ffffffff89dfe8c6>] dump_stack+0x4d/0x66
> > [ 0.000000] [<ffffffff89a81df3>] warn_slowpath_common+0x73/0x90
> > [ 0.000000] [<ffffffff89a81e57>] warn_slowpath_fmt+0x47/0x50
> > [ 0.000000] [<ffffffff89acaadf>] ? rcu_check_callbacks+0x30f/0x7c0
> > [ 0.000000] [<ffffffff89a1396e>] warn_pre_alternatives+0x1e/0x20
> > [ 0.000000] [<ffffffff89aeddd5>] irq_work_tick+0x15/0x50
> > [ 0.000000] [<ffffffff89acfae6>] update_process_times+0x56/0x70
> > [ 0.000000] [<ffffffff89adae2b>] tick_periodic+0x2b/0xc0
> > [ 0.000000] [<ffffffff89adb0d1>] ? tick_handle_periodic+0x21/0x60
> > [ 0.000000] [<ffffffff89adb0d1>] tick_handle_periodic+0x21/0x60
> > [ 0.000000] [<ffffffff89a05500>] timer_interrupt+0x10/0x20
> > [ 0.000000] [<ffffffff89ac1ef4>] handle_irq_event_percpu+0x64/0x110
> > [ 0.000000] [<ffffffff89ac1fd8>] handle_irq_event+0x38/0x60
> > [ 0.000000] [<ffffffff89ac4c24>] handle_level_irq+0x74/0x110
> > [ 0.000000] [<ffffffff89a04cf8>] handle_irq+0x58/0x150
> > [ 0.000000] [<ffffffff89aa8e89>] ? vtime_account_idle+0x9/0x50
> > [ 0.000000] [<ffffffff89aa8f0d>] ? vtime_common_account_irq_enter+0x3d/0x50
> > [ 0.000000] [<ffffffff89a04598>] do_IRQ+0x48/0xe0
> > [ 0.000000] [<ffffffff89e063ed>] common_interrupt+0x6d/0x6d
> > [ 0.000000] <EOI> [<ffffffff89a2f0a6>] ? native_restore_fl+0x6/0x10
> > [ 0.000000] [<ffffffff89e04ea1>] _raw_spin_unlock_irqrestore+0x31/0x40
> > [ 0.000000] [<ffffffff89ac3845>] __setup_irq+0x255/0x580
> > [ 0.000000] [<ffffffff89ac3bac>] setup_irq+0x3c/0xa0
> > [ 0.000000] [<ffffffff8a529998>] ? hpet_enable+0x29a/0x2cb
> > [ 0.000000] [<ffffffff8a51cb9b>] setup_default_timer_irq+0x1e/0x20
> > [ 0.000000] [<ffffffff8a51cbb4>] hpet_time_init+0x17/0x19
> > [ 0.000000] [<ffffffff8a51cb76>] x86_late_time_init+0xa/0x11
> > [ 0.000000] [<ffffffff8a51ad8c>] start_kernel+0x383/0x3f8
> > [ 0.000000] [<ffffffff8a51a120>] ? early_idt_handlers+0x120/0x120
> > [ 0.000000] [<ffffffff8a51a432>] x86_64_start_reservations+0x2a/0x2c
> > [ 0.000000] [<ffffffff8a51a50b>] x86_64_start_kernel+0xd7/0xe4
>
> So the issue here seems to be that something enabled irqs on boot way too early.
> But I tried hard to reproduce that crash without success. So I wanted to ask you,
> do you mind if I send you a patch to debug this?

Never mind. Feel free to send me the patch.

Thanks,
Fengguang
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