Bug#827323: linux: Regression v4.5 -> v4.6: system freeze after suspend/resume due to iAMT watchdog

["Usyskin, Alexander" <alexander.usyskin@intel.com>]

Hi

I assume that "This happened with 4.6, but not with v4.5.", yes?

Do you have vPro system? Have you provisioned your ME device?
If not, the iAMT watchdog should not be exposed to user-space and should not affect systemd.
Do you have /dev/watchdog* with identity "iamt_wdt" at you system?

Thanks
--
Sasha


-----Original Message-----
From: Sebastian Reichel [mailto:sre@debian.org] 
Sent: Wednesday, June 15, 2016 02:44
To: Debian Bug Tracking System <submit@bugs.debian.org>
Subject: Bug#827323: linux: Regression v4.5 -> v4.6: system freeze after suspend/resume due to iAMT watchdog

Source: linux
Version: 4.5.5-1
Severity: normal

Hi,

My Lenovo Thinkpad X250 freezes a couple of seconds after resuming from suspend. This happened with 4.5, but not with v4.6. I bisected the problem using mainline kernel with Debian config to the following commit:

sre@earth ~/src/linux (git)-[fdd9b86...|bisect] % git bisect bad fdd9b8655933c3eb3154fe1ed351c17b654258bd is the first bad commit commit fdd9b8655933c3eb3154fe1ed351c17b654258bd
Author: Alexander Usyskin <alexander.usyskin@intel.com>
Date:   Fri Jan 8 00:49:21 2016 +0200

    mei: wd: drop the watchdog code from the core mei driver
    
    Instead of integrating the iAMT watchdog in the mei core driver
    we will create a watchdog device on the mei client bus and
    create a driver for it.
    
    This patch removes the watchdog code from the mei core driver.
    
    Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
    Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

My system was configured to use the watchdog via "RuntimeWatchdogSec=30"
in "/etc/systemd/system.conf". After disabling the feature no system freeze happens after suspend/resume cycle.

-- Sebastian

-- System Information:
Debian Release: stretch/sid
  APT prefers testing
  APT policy: (1000, 'testing'), (500, 'unstable'), (200, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386, armhf

Kernel: Linux 4.6.0-1-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
---------------------------------------------------------------------
Intel Israel (74) Limited

This e-mail and any attachments may contain confidential material for
the sole use of the intended recipient(s). Any review or distribution
by others is strictly prohibited. If you are not the intended
recipient, please contact the sender and delete all copies.