From: Tom Zanussi <zanussi@kernel.org>
To: linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org
Cc: rostedt@goodmis.org, tglx@linutronix.de, C.Emde@osadl.org,
jkacur@redhat.com, bigeasy@linutronix.de,
daniel.wagner@siemens.com, julia@ni.com, amartin@nvidia.com
Subject: [PATCH 08/13] hrtimer: Don't lose state in cpu_chill()
Date: Mon, 8 Apr 2019 14:14:10 -0500 [thread overview]
Message-ID: <53a19e573f13967322ba8221fcf121948803ccf4.1554737688.git.tom.zanussi@linux.intel.com> (raw)
In-Reply-To: <cover.1554737688.git.tom.zanussi@linux.intel.com>
In-Reply-To: <cover.1554737688.git.tom.zanussi@linux.intel.com>
4.14.109-rt58-rc1 stable review patch.
If anyone has any objections, please let me know.
------------------
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
[ Upstream commit 585456236766349f692f9fbcc089d71411831f88 ]
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>
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
---
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 c8d806126381..6da6b5dded3c 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -1866,15 +1866,18 @@ 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
--
2.14.1
next prev parent reply other threads:[~2019-04-08 19:15 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-08 19:14 [PATCH 00/13] Linux 4.14.109-rt58-rc1 Tom Zanussi
2019-04-08 19:14 ` [PATCH 01/13] arm64: fpsimd: use preemp_disable in addition to local_bh_disable() Tom Zanussi
2019-04-08 19:14 ` [PATCH 02/13] sched/fair: Robustify CFS-bandwidth timer locking Tom Zanussi
2019-04-08 19:14 ` [PATCH 03/13] sched/fair: Make the hrtimers non-hard again Tom Zanussi
2019-04-08 19:14 ` [PATCH 04/13] locking/rt-mutex: Flush block plug on __down_read() Tom Zanussi
2019-04-08 19:14 ` [PATCH 05/13] rtmutex/rwlock: preserve state like a sleeping lock Tom Zanussi
2019-04-08 19:14 ` [PATCH 06/13] softirq: Avoid "local_softirq_pending" messages if ksoftirqd is blocked Tom Zanussi
2019-04-08 19:14 ` [PATCH 07/13] softirq: Avoid "local_softirq_pending" messages if task is in cpu_chill() Tom Zanussi
2019-04-08 19:14 ` Tom Zanussi [this message]
2019-04-08 19:14 ` [PATCH 09/13] x86: lazy-preempt: properly check against preempt-mask Tom Zanussi
2019-04-08 19:14 ` [PATCH 10/13] hrtimer: cpu_chill(): save task state in ->saved_state() Tom Zanussi
2019-04-08 19:14 ` [PATCH 11/13] tty/sysrq: Convert show_lock to raw_spinlock_t Tom Zanussi
2019-04-08 19:14 ` [PATCH 12/13] powerpc/pseries/iommu: Use a locallock instead local_irq_save() Tom Zanussi
2019-04-08 19:14 ` [PATCH 13/13] Linux 4.14.109-rt58 Tom Zanussi
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