Re: watchdog: how to enable?

[Muni Sekhar <munisekharrms@gmail.com>]

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.

$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