Re: watchdog: how to enable?

[Muni Sekhar <munisekharrms@gmail.com>]

On Fri, Nov 22, 2019 at 4:29 PM Guenter Roeck <linux@roeck-us.net> wrote:
>
> On 11/18/19 7:09 AM, Muni Sekhar wrote:
> > On Mon, Nov 18, 2019 at 8:08 PM Bjorn Helgaas <helgaas@kernel.org> wrote:
> >>
> >> [-cc linux-pci (nothing here is PCI-specific)]
> >>
> >> On Sat, Nov 16, 2019 at 06:05:05AM +0530, Muni Sekhar wrote:
> >>> My kernel is built with the following options:
> >>>
> >>> $ cat /boot/config-5.0.1 | grep NO_HZ
> >>> CONFIG_NO_HZ_COMMON=y
> >>> CONFIG_NO_HZ_IDLE=y
> >>> # CONFIG_NO_HZ_FULL is not set
> >>> CONFIG_NO_HZ=y
> >>> CONFIG_RCU_FAST_NO_HZ=y
> >>>
> >>> I booted with watchdog enabled(nmi_watchdog=1) as given below:
> >>>
> >>> BOOT_IMAGE=/boot/vmlinuz-5.0.1
> >>> root=UUID=f65454ae-3f1d-4b9e-b4be-74a29becbe1e ro debug
> >>> ignore_loglevel console=ttyUSB0,115200 console=tty0 console=tty1
> >>> console=ttyS2,115200 memmap=1M!1023M nmi_watchdog=1
> >>> crashkernel=384M-:128M
> >>>
> >>> When the system is frozen or the kernel is locked up(I noticed that in
> >>> this state kernel is not responding for ALT-SysRq-<command key>) but
> >>> watchdog is not triggered. So I want to understand how to enable the
> >>> watchdog timer and how to verify the basic watchdog functionality
> >>> behavior?
> >>
> >> I don't know much about the watchdog, but I assume you've found these
> >> already?
> >>
> >>    Documentation/admin-guide/lockup-watchdogs.rst
> >>    Documentation/admin-guide/sysctl/kernel.rst
> >>
> >> Do you have CONFIG_HAVE_NMI_WATCHDOG=y?  (See arch/Kconfig)
> >
> > I don’t have CONFIG_HAVE_NMI_WATCHDOG in kernel .config file.
> >
>
> That would mean you don't have NMI in the first place. What is your
> architecture ?

My system has “Intel(R) Atom(TM) CPU  E3845” processor and running
‘uname -m’ gives x86_64.

/proc/interrupts gives the below statistics for NMI:

$ cat /proc/interrupts | grep NMI
 NMI:       4207       4167        125   Non-maskable interrupts


>
> Guenter
>
> > $cat /boot/config-5.0.1 | grep CONFIG_HAVE_NMI_WATCHDOG
> >
> > But tried to enable CONFIG_HAVE_NMI_WATCHDOG via menuconfig, but could
> > not able to find it. What is the role of CONFIG_HAVE_NMI_WATCHDOG?
> >
> > Symbol: HAVE_NMI_WATCHDOG [=n]
> >
> >                                              │
> >    │ Type  : bool
> >
> >                                                  │
> >    │   Defined at arch/Kconfig:339
> >
> >                                                  │
> >    │   Depends on: HAVE_NMI [=y]
> >
> >                                                  │
> >    │   Selected by [n]:
> >
> >                                                  │
> >    │   - HAVE_HARDLOCKUP_DETECTOR_ARCH [=n]
> >
> >
> >    │ Symbol: HAVE_HARDLOCKUP_DETECTOR_ARCH [=n]
> >
> >                                                  │
> >    │ Type  : bool
> >
> >                                                  │
> >    │   Defined at arch/Kconfig:346
> >
> >                                                  │
> >    │   Selects: HAVE_NMI_WATCHDOG [=n]
> >
> >
> >
> >
> >
>


-- 
Thanks,
Sekhar