From: Sebastian Andrzej Siewior bigeasy@linutronix.de
stable inclusion from stable-5.10.69 commit 83a3cb200effb8f61d51516bd64fd94dea4c7805 bugzilla: 182675 https://gitee.com/openeuler/kernel/issues/I4I3ED
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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[ Upstream commit 9848417926353daa59d2b05eb26e185063dbac6e ]
The intel powerclamp driver will setup a per-CPU worker with RT priority. The worker will then invoke play_idle() in which it remains in the idle poll loop until it is stopped by the timer it started earlier.
That timer needs to expire in hard interrupt context on PREEMPT_RT. Otherwise the timer will expire in ksoftirqd as a SOFT timer but that task won't be scheduled on the CPU because its priority is lower than the priority of the worker which is in the idle loop.
Always expire the idle timer in hard interrupt context.
Reported-by: Thomas Gleixner tglx@linutronix.de Signed-off-by: Sebastian Andrzej Siewior bigeasy@linutronix.de Signed-off-by: Thomas Gleixner tglx@linutronix.de Link: https://lore.kernel.org/r/20210906113034.jgfxrjdvxnjqgtmc@linutronix.de Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Chen Jun chenjun102@huawei.com Acked-by: Weilong Chen chenweilong@huawei.com
Signed-off-by: Chen Jun chenjun102@huawei.com --- kernel/sched/idle.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c index ae823c329fd7..2e1db13b863f 100644 --- a/kernel/sched/idle.c +++ b/kernel/sched/idle.c @@ -430,10 +430,10 @@ void play_idle_precise(u64 duration_ns, u64 latency_ns) cpuidle_use_deepest_state(latency_ns);
it.done = 0; - hrtimer_init_on_stack(&it.timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); + hrtimer_init_on_stack(&it.timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD); it.timer.function = idle_inject_timer_fn; hrtimer_start(&it.timer, ns_to_ktime(duration_ns), - HRTIMER_MODE_REL_PINNED); + HRTIMER_MODE_REL_PINNED_HARD);
while (!READ_ONCE(it.done)) do_idle();