From: Junxiao Chang Date: Mon, 20 Feb 2023 09:12:20 +0100 Subject: [PATCH] softirq: Wake ktimers thread also in softirq. Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.7/older/patches-6.7-rt6.tar.xz If the hrtimer is raised while a softirq is processed then it does not wake the corresponding ktimers thread. This is due to the optimisation in the irq-exit path which is also used to wake the ktimers thread. For the other softirqs, this is okay because the additional softirq bits will be handled by the currently running softirq handler. The timer related softirq bits are added to a different variable and rely on the ktimers thread. As a consuequence the wake up of ktimersd is delayed until the next timer tick. Always wake the ktimers thread if a timer related softirq is pending. Reported-by: Peh, Hock Zhang Signed-off-by: Junxiao Chang Signed-off-by: Sebastian Andrzej Siewior --- kernel/softirq.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -646,13 +646,12 @@ static inline void __irq_exit_rcu(void) #endif account_hardirq_exit(current); preempt_count_sub(HARDIRQ_OFFSET); - if (!in_interrupt()) { - if (local_softirq_pending()) - invoke_softirq(); + if (!in_interrupt() && local_softirq_pending()) + invoke_softirq(); - if (IS_ENABLED(CONFIG_PREEMPT_RT) && local_pending_timers()) - wake_timersd(); - } + if (IS_ENABLED(CONFIG_PREEMPT_RT) && local_pending_timers() && + !(in_nmi() | in_hardirq())) + wake_timersd(); tick_irq_exit(); }