From c1a957d17086d20d52d7f9c8dffaeac2ee09d6f9 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Fri, 25 May 2018 17:54:41 +0200 Subject: 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 [bigeasy: cover s2idle in tick_freeze() / tick_unfreeze()] Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Rafael J. Wysocki --- kernel/power/suspend.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'kernel/power/suspend.c') diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c index 4c10be0f4843..5149c77506b3 100644 --- a/kernel/power/suspend.c +++ b/kernel/power/suspend.c @@ -428,6 +428,8 @@ static int suspend_enter(suspend_state_t state, bool *wakeup) arch_suspend_disable_irqs(); BUG_ON(!irqs_disabled()); + system_state = SYSTEM_SUSPEND; + error = syscore_suspend(); if (!error) { *wakeup = pm_wakeup_pending(); @@ -443,6 +445,8 @@ static int suspend_enter(suspend_state_t state, bool *wakeup) syscore_resume(); } + system_state = SYSTEM_RUNNING; + arch_suspend_enable_irqs(); BUG_ON(irqs_disabled()); -- cgit v1.2.3