From: Sebastian Capella <sebastian.capella@linaro.org>
Date: Wed, 19 Feb 2014 01:52:08 +0000 (-0800)
Subject: PM / hibernate: Fix restore hang in freeze_processes()
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=f8d5b9e9e5372f0deb7bc1ab1088a9b60b0a793d;p=linux.git

PM / hibernate: Fix restore hang in freeze_processes()

During restore, pm_notifier chain are called with
PM_RESTORE_PREPARE.  The firmware_class driver handler
fw_pm_notify does not have a handler for this.  As a result,
it keeps a reader on the kmod.c umhelper_sem.  During
freeze_processes, the call to __usermodehelper_disable tries to
take a write lock on this semaphore and hangs waiting.

Signed-off-by: Sebastian Capella <sebastian.capella@linaro.org>
Acked-by: Ming Lei <ming.lei@canonical.com>
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---

diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c
index 8a97ddfa61222..c30df50e4440c 100644
--- a/drivers/base/firmware_class.c
+++ b/drivers/base/firmware_class.c
@@ -1580,6 +1580,7 @@ static int fw_pm_notify(struct notifier_block *notify_block,
 	switch (mode) {
 	case PM_HIBERNATION_PREPARE:
 	case PM_SUSPEND_PREPARE:
+	case PM_RESTORE_PREPARE:
 		kill_requests_without_uevent();
 		device_cache_fw_images();
 		break;