From: Thomas Gleixner <[email protected]>

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().

Signed-off-by: Thomas Gleixner <[email protected]>
[bigeasy: cover s2idle]
Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
---
 include/linux/kernel.h   | 1 +
 kernel/power/hibernate.c | 7 +++++++
 kernel/power/suspend.c   | 6 ++++++
 3 files changed, 14 insertions(+)

diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 6a1eb0b0aad9..7aed92624531 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -542,6 +542,7 @@ extern enum system_states {
        SYSTEM_HALT,
        SYSTEM_POWER_OFF,
        SYSTEM_RESTART,
+       SYSTEM_SUSPEND,
 } system_state;
 
 /* This cannot be an enum because some may be used in assembly source. */
diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index 5454cc639a8d..9c85c7822383 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -287,6 +287,8 @@ static int create_image(int platform_mode)
 
        local_irq_disable();
 
+       system_state = SYSTEM_SUSPEND;
+
        error = syscore_suspend();
        if (error) {
                pr_err("Some system devices failed to power down, aborting 
hibernation\n");
@@ -317,6 +319,7 @@ static int create_image(int platform_mode)
        syscore_resume();
 
  Enable_irqs:
+       system_state = SYSTEM_RUNNING;
        local_irq_enable();
 
  Enable_cpus:
@@ -445,6 +448,7 @@ static int resume_target_kernel(bool platform_mode)
                goto Enable_cpus;
 
        local_irq_disable();
+       system_state = SYSTEM_SUSPEND;
 
        error = syscore_suspend();
        if (error)
@@ -478,6 +482,7 @@ static int resume_target_kernel(bool platform_mode)
        syscore_resume();
 
  Enable_irqs:
+       system_state = SYSTEM_RUNNING;
        local_irq_enable();
 
  Enable_cpus:
@@ -563,6 +568,7 @@ int hibernation_platform_enter(void)
                goto Enable_cpus;
 
        local_irq_disable();
+       system_state = SYSTEM_SUSPEND;
        syscore_suspend();
        if (pm_wakeup_pending()) {
                error = -EAGAIN;
@@ -575,6 +581,7 @@ int hibernation_platform_enter(void)
 
  Power_up:
        syscore_resume();
+       system_state = SYSTEM_RUNNING;
        local_irq_enable();
 
  Enable_cpus:
diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index 4c10be0f4843..9108a99878bf 100644
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c
@@ -110,6 +110,7 @@ static void s2idle_loop(void)
 {
        pm_pr_dbg("suspend-to-idle\n");
 
+       system_state = SYSTEM_SUSPEND;
        for (;;) {
                int error;
 
@@ -148,6 +149,7 @@ static void s2idle_loop(void)
 
                pm_wakeup_clear(false);
        }
+       system_state = SYSTEM_RUNNING;
 
        pm_pr_dbg("resume from suspend-to-idle\n");
 }
@@ -428,6 +430,8 @@ 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 +447,8 @@ static int suspend_enter(suspend_state_t state, bool 
*wakeup)
                syscore_resume();
        }
 
+       system_state = SYSTEM_RUNNING;
+
        arch_suspend_enable_irqs();
        BUG_ON(irqs_disabled());
 
-- 
2.17.0

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