![]() Taking a cpu offline removes the cpu from the online mask before the CPU_DEAD notification is done. The clock events layer does the cleanup of the dead CPU from the CPU_DEAD notifier chain. tick_do_timer_cpu is used to avoid xtime lock contention by assigning the task of jiffies xtime updates to one CPU. If a CPU is taken offline, then this assignment becomes stale. This went unnoticed because most of the time the offline CPU went dead before the online CPU reached __cpu_die(), where the CPU_DEAD state is checked. In the case that the offline CPU did not reach the DEAD state before we reach __cpu_die(), the code in there goes to sleep for 100ms. Due to the stale time update assignment, the system is stuck forever. Take the assignment away when a cpu is not longer in the cpu_online_mask. We do this in the last call to tick_nohz_stop_sched_tick() when the offline CPU is on the way to the final play_dead() idle entry. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> |
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.. | ||
clockevents.c | ||
clocksource.c | ||
jiffies.c | ||
Kconfig | ||
Makefile | ||
ntp.c | ||
tick-broadcast.c | ||
tick-common.c | ||
tick-internal.h | ||
tick-oneshot.c | ||
tick-sched.c | ||
timekeeping.c | ||
timer_list.c | ||
timer_stats.c |