From 2e4448f4f95761e2aa4a7b259121061635170dd4 Mon Sep 17 00:00:00 2001
From: Junxiao Chang <junxiao.chang@intel.com>
Date: Mon, 20 Feb 2023 09:12:20 +0100
Subject: [PATCH 15/63] softirq: Wake ktimers thread also in softirq.

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 <hock.zhang.peh@intel.com>
Signed-off-by: Junxiao Chang <junxiao.chang@intel.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 kernel/softirq.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/kernel/softirq.c b/kernel/softirq.c
index c7331f0c7021..24d0cb2a2338 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -668,13 +668,12 @@ 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();
 }
-- 
2.46.0

