[3.8.y.z extended stable] Patch "PM / hibernate: Fix restore hang in freeze_processes()" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    PM / hibernate: Fix restore hang in freeze_processes()

to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.20.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 68c3fec926ab92f175245d2cf6638ada02554f4c Mon Sep 17 00:00:00 2001
From: Sebastian Capella <sebastian.capella at linaro.org>
Date: Tue, 18 Feb 2014 17:52:08 -0800
Subject: PM / hibernate: Fix restore hang in freeze_processes()

commit f8d5b9e9e5372f0deb7bc1ab1088a9b60b0a793d upstream.

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 at linaro.org>
Acked-by: Ming Lei <ming.lei at canonical.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki at intel.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/base/firmware_class.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c
index b392b35..abb2054 100644
--- a/drivers/base/firmware_class.c
+++ b/drivers/base/firmware_class.c
@@ -1413,6 +1413,7 @@ static int fw_pm_notify(struct notifier_block *notify_block,
 	switch (mode) {
 	case PM_HIBERNATION_PREPARE:
 	case PM_SUSPEND_PREPARE:
+	case PM_RESTORE_PREPARE:
 		device_cache_fw_images();
 		break;

--
1.8.3.2