[PATCH 022/106] PM / Sleep: avoid 'autosleep' in shutdown progress

[Luis Henriques]

3.5.7.18 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Liu ShuoX <shuox.liu at intel.com>

commit e5248a111bf4048a9f3fab1a9c94c4630a10592a upstream.

Prevent automatic system suspend from happening during system
shutdown by making try_to_suspend() check system_state and return
immediately if it is not SYSTEM_RUNNING.

This prevents the following breakage from happening (scenario from
Zhang Yanmin):

 Kernel starts shutdown and calls all device driver's shutdown
 callback.  When a driver's shutdown is called, the last wakelock is
 released and suspend-to-ram starts.  However, as some driver's shut
 down callbacks already shut down devices and disabled runtime pm,
 the suspend-to-ram calls driver's suspend callback without noticing
 that device is already off and causes crash.

[rjw: Changelog]
Signed-off-by: Liu ShuoX <shuox.liu at intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki at intel.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 kernel/power/autosleep.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/power/autosleep.c b/kernel/power/autosleep.c
index ca304046..ab79ecb 100644
--- a/kernel/power/autosleep.c
+++ b/kernel/power/autosleep.c
@@ -32,7 +32,8 @@ static void try_to_suspend(struct work_struct *work)
 
 	mutex_lock(&autosleep_lock);
 
-	if (!pm_save_wakeup_count(initial_count)) {
+	if (!pm_save_wakeup_count(initial_count) ||
+		system_state != SYSTEM_RUNNING) {
 		mutex_unlock(&autosleep_lock);
 		goto out;
 	}
-- 
1.8.3.2