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authorThomas Gleixner <tglx@linutronix.de>2018-05-25 17:54:41 +0200
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2018-05-27 11:55:02 +0200
commitc1a957d17086d20d52d7f9c8dffaeac2ee09d6f9 (patch)
tree55fd308201993a3caf2b2df2bf23ab9ef2ed5718 /kernel/time
parent771c577c23bac90597c685971d7297ea00f99d11 (diff)
downloadop-kernel-dev-c1a957d17086d20d52d7f9c8dffaeac2ee09d6f9.zip
op-kernel-dev-c1a957d17086d20d52d7f9c8dffaeac2ee09d6f9.tar.gz
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.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c
index 49edc1c..14de372 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 {
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