diff options
Diffstat (limited to 'debian/patches-rt/0300-sched-Switch-wait_task_inactive-to-HRTIMER_MODE_REL_.patch')
| -rw-r--r-- | debian/patches-rt/0300-sched-Switch-wait_task_inactive-to-HRTIMER_MODE_REL_.patch | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/debian/patches-rt/0300-sched-Switch-wait_task_inactive-to-HRTIMER_MODE_REL_.patch b/debian/patches-rt/0300-sched-Switch-wait_task_inactive-to-HRTIMER_MODE_REL_.patch new file mode 100644 index 000000000..720b08fc7 --- /dev/null +++ b/debian/patches-rt/0300-sched-Switch-wait_task_inactive-to-HRTIMER_MODE_REL_.patch @@ -0,0 +1,48 @@ +From f29a6f7bb4568b4ac2d5a9226d503db7a2c69bab 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 300/323] sched: Switch wait_task_inactive to + HRTIMER_MODE_REL_HARD +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.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> +Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> +--- + 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 81b342d6629b..6735872a8508 100644 +--- a/kernel/sched/core.c ++++ b/kernel/sched/core.c +@@ -2739,7 +2739,7 @@ unsigned long wait_task_inactive(struct task_struct *p, long 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; + } + +-- +2.43.0 + |