PM / Sleep: avoid 'autosleep' in shutdown progress

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@intel.com>
Cc: 3.5+ <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/kernel/power/autosleep.c b/kernel/power/autosleep.c
index c6422ffeda9a..9012ecf7b814 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;
         }