From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: linux-rt-users@vger.kernel.org
Cc: linux-kernel@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>,
Steven Rostedt <rostedt@goodmis.org>
Subject: [PATCH RT 4/2] hrtimer: Don't lose state in cpu_chill()
Date: Tue, 19 Feb 2019 17:08:43 +0100 [thread overview]
Message-ID: <20190219160842.qxpwicoa5tzq4njo@linutronix.de> (raw)
In-Reply-To: <20190219160755.fn4c65ph4lzqflw2@linutronix.de>
In cpu_chill() the state is set to TASK_UNINTERRUPTIBLE and a timer is
programmed. On return the state is always TASK_RUNNING which means we
lose the state if it was something other than RUNNING. Also
set_current_state() sets ->task_state_change to within cpu_chill() which
is not expected.
Save the task state on entry and restore it on return. Simply set the
state in order to avoid updating ->task_state_change.
Cc: stable-rt@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
kernel/time/hrtimer.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index 851b2134e77f4..6f2736ec4b8ef 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -1902,15 +1902,18 @@ void cpu_chill(void)
{
ktime_t chill_time;
unsigned int freeze_flag = current->flags & PF_NOFREEZE;
+ long saved_state;
+ saved_state = current->state;
chill_time = ktime_set(0, NSEC_PER_MSEC);
- set_current_state(TASK_UNINTERRUPTIBLE);
+ __set_current_state_no_track(TASK_UNINTERRUPTIBLE);
current->flags |= PF_NOFREEZE;
sleeping_lock_inc();
schedule_hrtimeout(&chill_time, HRTIMER_MODE_REL_HARD);
sleeping_lock_dec();
if (!freeze_flag)
current->flags &= ~PF_NOFREEZE;
+ __set_current_state_no_track(saved_state);
}
EXPORT_SYMBOL(cpu_chill);
#endif
--
2.20.1
next prev parent reply other threads:[~2019-02-19 16:08 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-18 16:31 [PATCH RT 1/2] softirq: Avoid "local_softirq_pending" messages if ksoftirqd is blocked Sebastian Andrzej Siewior
2019-02-18 16:31 ` [PATCH RT 2/2] x86: lazy-preempt: properly check against preempt-mask Sebastian Andrzej Siewior
2019-02-19 16:07 ` [PATCH RT 3/2] softirq: Avoid "local_softirq_pending" messages if task is in cpu_chill() Sebastian Andrzej Siewior
2019-02-19 16:08 ` Sebastian Andrzej Siewior [this message]
2019-02-25 14:43 ` [PATCH RT 4/2] hrtimer: Don't lose state " Mike Galbraith
2019-02-25 16:34 ` Sebastian Andrzej Siewior
2019-02-25 17:40 ` Mike Galbraith
2019-02-26 11:38 ` Sebastian Andrzej Siewior
2019-02-19 14:58 ` [PATCH RT 1/2] softirq: Avoid "local_softirq_pending" messages if ksoftirqd is blocked Juri Lelli
2019-02-19 16:06 ` Sebastian Andrzej Siewior
2019-02-19 16:27 ` Juri Lelli
2019-02-19 16:28 ` Sebastian Andrzej Siewior
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