On Wed, 27 Mar 2019, Oleg Nesterov wrote: > On 03/26, Thomas Gleixner wrote: > > > > The rework of the watchdog core to use cpu_stop_work broke the watchdog > > cpumask on CPU hotplug. > > > > The watchdog_enable/disable() functions are now called unconditionally from > > the hotplug callback, i.e. even on CPUs which are not in the watchdog > > cpumask. > > > > Only invoke them when the plugged CPU is in the watchdog cpumask. > > IIUC without this fix an NMI watchdog can too be enabled at boot time even > if the initial watchdog_cpumask = housekeeping_cpumask(HK_FLAG_TIMER) doesn't > include the plugged CPU.
Yes. > And after that writing 0 to /proc/sys/kernel/nmi_watchdog clears > NMI_WATCHDOG_ENABLED but this can't disable NMI watchdog's outside of > watchdog_allowed_mask. Correct > So may be this can explain the problem reported by Maxime ? > See > https://lore.kernel.org/lkml/b99c5a25-a5fe-18dd-2f1d-bdd6834f0...@redhat.com/ That looks so. Thanks, tglx
