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| author | Thomas Gleixner <tglx@linutronix.de> | 2018-05-25 17:54:41 +0200 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2018-05-27 11:55:02 +0200 |
| commit | c1a957d17086d20d52d7f9c8dffaeac2ee09d6f9 (patch) | |
| tree | 55fd308201993a3caf2b2df2bf23ab9ef2ed5718 /kernel/time | |
| parent | Linux 4.17-rc6 (diff) | |
| download | linux-c1a957d17086d20d52d7f9c8dffaeac2ee09d6f9.tar.xz linux-c1a957d17086d20d52d7f9c8dffaeac2ee09d6f9.zip | |
PM / suspend: Prevent might sleep splats
timekeeping suspend/resume calls read_persistent_clock() which takes
rtc_lock. That results in might sleep warnings because at that point
we run with interrupts disabled.
We cannot convert rtc_lock to a raw spinlock as that would trigger
other might sleep warnings.
As a workaround we disable the might sleep warnings by setting
system_state to SYSTEM_SUSPEND before calling sysdev_suspend() and
restoring it to SYSTEM_RUNNING afer sysdev_resume(). There is no lock
contention because hibernate / suspend to RAM is single-CPU at this
point.
In s2idle's case the system_state is set to SYSTEM_SUSPEND before
timekeeping_suspend() which is invoked by the last CPU. In the resume
case it set back to SYSTEM_RUNNING after timekeeping_resume() which is
invoked by the first CPU in the resume case. The other CPUs will block
on tick_freeze_lock.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[bigeasy: cover s2idle in tick_freeze() / tick_unfreeze()]
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'kernel/time')
| -rw-r--r-- | kernel/time/tick-common.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c index 49edc1c4f3e6..14de3727b18e 100644 --- a/kernel/time/tick-common.c +++ b/kernel/time/tick-common.c @@ -490,6 +490,7 @@ void tick_freeze(void) if (tick_freeze_depth == num_online_cpus()) { trace_suspend_resume(TPS("timekeeping_freeze"), smp_processor_id(), true); + system_state = SYSTEM_SUSPEND; timekeeping_suspend(); } else { tick_suspend_local(); @@ -513,6 +514,7 @@ void tick_unfreeze(void) if (tick_freeze_depth == num_online_cpus()) { timekeeping_resume(); + system_state = SYSTEM_RUNNING; trace_suspend_resume(TPS("timekeeping_freeze"), smp_processor_id(), false); } else { |