Re: [PATCH] reboot: Backup orderly_poweroff

From: Keerthy
Date: Tue Jan 12 2016 - 23:26:53 EST

On Monday 11 January 2016 08:25 PM, Josh Triplett wrote:
On Mon, Jan 11, 2016 at 03:53:24PM +0530, Keerthy wrote:
orderly_poweroff is triggered when a graceful shutdown
of system is desired. This may be used in many critical states of the
kernel such as when subsystems detects conditions such as critical
temperature conditions. However, in certain conditions in system
boot up sequences like those in the middle of driver probes being
initiated, userspace will be unable to power off the system in a clean
manner and leaves the system in a critical state. In cases like these,
the /sbin/poweroff will return success (having forked off to attempt
powering off the system. However, the system overall will fail to
completely poweroff (since other modules will be probed) and the system
is still functional with no userspace (since that would have shut itself

However, there is no clean way of detecting such failure of userspace
powering off the system. In such scenarios, it is necessary for a backup
workqueue to be able to force a shutdown of the system when orderly
shutdown is not successful after a configurable time period.

One issue below, inline.

Signed-off-by: Keerthy <j-keerthy@xxxxxx>
Suggested-by: Eduardo Valentin <edubezval@xxxxxxxxx>
Reported-by: Nishanth Menon <nm@xxxxxx>
Links to previous discussion can be found here:

Boot tested on DRA7.

arch/Kconfig | 7 +++++++
kernel/reboot.c | 23 ++++++++++++++++++-----
2 files changed, 25 insertions(+), 5 deletions(-)

Index: linux/arch/Kconfig
--- linux.orig/arch/Kconfig 2016-01-11 15:26:07.732173131 +0530
+++ linux/arch/Kconfig 2016-01-11 15:26:07.728173205 +0530
@@ -37,6 +37,18 @@
def_bool y

+ int "Backup shutdown delay in milli-seconds"
+ default 0

With no dependencies, as far as I can tell this will always get defined
with a value, defaulting to 0. (I don't know of any special cases in
Kconfig for an int value of 0.) Thus, in the code below...

Yes. I will fix this and post a new version. Thanks for the review.


--- linux.orig/kernel/reboot.c 2016-01-11 15:26:07.732173131 +0530
+++ linux/kernel/reboot.c 2016-01-11 15:38:33.502341511 +0530
@@ -424,6 +424,38 @@
return ret;


...this should use #if, not #ifdef. Otherwise this code will get
compiled into every kernel.

- Josh Triplett