During clock_settime absolute realtime timers may get updated to expire sooner in absolute monotonic time but if hrtimer_force_reprogram is called as part of a clock_settime and the next hard hrtimer expires before the next soft hrtimer softirq_expires_next will not be updated to reflect this change (assuming the realtime timer is a soft timer).
This means that if the next soft hrtimer expires before softirq_expires_next but after now no soft hrtimer interrupt will be raised in hrtimer_interrupt which will instead retry tick_program_event three times before forcing a tick_program_event using a very short delay entering hrtimer_interrupt again almost immediately repeating the process over and over again until now exceeds softirq_expires_next and a soft hrtimer interrupt is finally raised. This patch aims to solve this by always updating softirq_expires_next if a soft hrtimer exists. Signed-off-by: Mikael Beckius <[email protected]> --- kernel/time/hrtimer.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c index 743c852e10f2..e4c233f404b1 100644 --- a/kernel/time/hrtimer.c +++ b/kernel/time/hrtimer.c @@ -633,7 +633,7 @@ hrtimer_force_reprogram(struct hrtimer_cpu_base *cpu_base, int skip_equal) */ expires_next = __hrtimer_get_next_event(cpu_base, HRTIMER_ACTIVE_ALL); - if (cpu_base->next_timer && cpu_base->next_timer->is_soft) { + if (cpu_base->softirq_next_timer) { /* * When the softirq is activated, hrtimer has to be * programmed with the first hard hrtimer because soft @@ -643,7 +643,8 @@ hrtimer_force_reprogram(struct hrtimer_cpu_base *cpu_base, int skip_equal) expires_next = __hrtimer_get_next_event(cpu_base, HRTIMER_ACTIVE_HARD); else - cpu_base->softirq_expires_next = expires_next; + cpu_base->softirq_expires_next = __hrtimer_get_next_event(cpu_base, + HRTIMER_ACTIVE_SOFT); } if (skip_equal && expires_next == cpu_base->expires_next) -- 2.28.0
