Documentation/timers/no_hz.rst states that the "nohz_full=" mask must not
include the boot CPU, which is no longer true after:
08ae95f4fd ("nohz_full: Allow the boot CPU to be nohz_full").
However after:
aae17ebb53cd ("workqueue: Avoid using isolated cpus' timers on queue_delayed_work")
the kernel will crash at boot time in this case; housekeeping_any_cpu()
returns an invalid CPU number until smp_init() brings the first
housekeeping CPU up.
Change housekeeping_any_cpu() to check the result of cpumask_any_and() and
return smp_processor_id() in this case.
This is just the simple and backportable workaround which fixes the
symptom, but smp_processor_id() at boot time should be safe at least for
type == HK_TYPE_TIMER, this more or less matches the tick_do_timer_boot_cpu
logic.
There is no worry about cpu_down(); tick_nohz_cpu_down() will not allow to
offline tick_do_timer_cpu (the 1st online housekeeping CPU).
[ Apply only documentation changes as commit which causes boot
crash when boot CPU is nohz_full is not backported to stable
kernels - Krishanth ]
Reported-by: Chris von Recklinghausen <[email protected]>
Signed-off-by: Oleg Nesterov <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Reviewed-by: Phil Auld <[email protected]>
Acked-by: Frederic Weisbecker <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Closes: https://lore.kernel.org/all/[email protected]/
Signed-off-by: Krishanth Jagaduri <[email protected]>
[ strip out upstream commit and Fixes: so tools don't get confused that
this commit actually does anything real - gregkh]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
769f2099d9