diff mbox

[RFC,v1,2/3] Fix hibernation restore hang in freeze_processes

Message ID 1392774729-3235-3-git-send-email-sebastian.capella@linaro.org (mailing list archive)
State Accepted, archived
Headers show

Commit Message

Sebastian Capella Feb. 19, 2014, 1:52 a.m. UTC
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>
Cc: Russ Dill <Russ.Dill@ti.com>
Cc: Ming Lei <ming.lei@canonical.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/base/firmware_class.c |    1 +
 1 file changed, 1 insertion(+)

Comments

Ming Lei Feb. 24, 2014, 7:09 a.m. UTC | #1
On Wed, Feb 19, 2014 at 9:52 AM, Sebastian Capella
<sebastian.capella@linaro.org> wrote:
> 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>
> Cc: Russ Dill <Russ.Dill@ti.com>
> Cc: Ming Lei <ming.lei@canonical.com>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Acked-by: Ming Lei <ming.lei@canonical.com>

Thanks,
--
Ming Lei
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diff mbox

Patch

diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c
index eb8fb94..e2b51f8 100644
--- a/drivers/base/firmware_class.c
+++ b/drivers/base/firmware_class.c
@@ -1541,6 +1541,7 @@  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;