diff options
Diffstat (limited to 'debian/patches-rt/0017-sched-Switch-wait_task_inactive-to-HRTIMER_MODE_REL_.patch')
| -rw-r--r-- | debian/patches-rt/0017-sched-Switch-wait_task_inactive-to-HRTIMER_MODE_REL_.patch | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/debian/patches-rt/0017-sched-Switch-wait_task_inactive-to-HRTIMER_MODE_REL_.patch b/debian/patches-rt/0017-sched-Switch-wait_task_inactive-to-HRTIMER_MODE_REL_.patch new file mode 100644 index 000000000..69e6b1074 --- /dev/null +++ b/debian/patches-rt/0017-sched-Switch-wait_task_inactive-to-HRTIMER_MODE_REL_.patch @@ -0,0 +1,47 @@ +From c12c9235290c517ea3420483ee9b9c9d84ecf43e Mon Sep 17 00:00:00 2001 +From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +Date: Tue, 24 Aug 2021 22:47:37 +0200 +Subject: [PATCH 017/158] sched: Switch wait_task_inactive to + HRTIMER_MODE_REL_HARD +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.15/older/patches-5.15.10-rt24.tar.xz + +With PREEMPT_RT enabled all hrtimers callbacks will be invoked in +softirq mode unless they are explicitly marked as HRTIMER_MODE_HARD. +During boot kthread_bind() is used for the creation of per-CPU threads +and then hangs in wait_task_inactive() if the ksoftirqd is not +yet up and running. +The hang disappeared since commit + 26c7295be0c5e ("kthread: Do not preempt current task if it is going to call schedule()") + +but enabling function trace on boot reliably leads to the freeze on boot +behaviour again. +The timer in wait_task_inactive() can not be directly used by an user +interface to abuse it and create a mass wake of several tasks at the +same time which would to long sections with disabled interrupts. +Therefore it is safe to make the timer HRTIMER_MODE_REL_HARD. + +Switch the timer to HRTIMER_MODE_REL_HARD. + +Cc: stable-rt@vger.kernel.org +Link: https://lkml.kernel.org/r/20210826170408.vm7rlj7odslshwch@linutronix.de +Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +--- + kernel/sched/core.c | 2 +- + 1 file changed, 1 insertion(+), 1 deletion(-) + +diff --git a/kernel/sched/core.c b/kernel/sched/core.c +index c5f12805300e..9d31a1b174d2 100644 +--- a/kernel/sched/core.c ++++ b/kernel/sched/core.c +@@ -3250,7 +3250,7 @@ unsigned long wait_task_inactive(struct task_struct *p, unsigned int match_state + ktime_t to = NSEC_PER_SEC / HZ; + + set_current_state(TASK_UNINTERRUPTIBLE); +- schedule_hrtimeout(&to, HRTIMER_MODE_REL); ++ schedule_hrtimeout(&to, HRTIMER_MODE_REL_HARD); + continue; + } + +-- +2.33.1 + |