On Fri, Nov 22, 2019 at 4:29 PM Guenter Roeck <linux@xxxxxxxxxxxx> wrote: > > On 11/18/19 7:09 AM, Muni Sekhar wrote: > > On Mon, Nov 18, 2019 at 8:08 PM Bjorn Helgaas <helgaas@xxxxxxxxxx> 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
