From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:47686 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754517AbcKUQb6 (ORCPT ); Mon, 21 Nov 2016 11:31:58 -0500 Subject: Patch "PM / sleep: don't suspend parent when async child suspend_{noirq, late} fails" has been added to the 4.4-stable tree To: briannorris@chromium.org, gregkh@linuxfoundation.org, jeffy.chen@rock-chips.com, rafael.j.wysocki@intel.com Cc: , From: Date: Mon, 21 Nov 2016 17:27:42 +0100 Message-ID: <147974566225238@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled PM / sleep: don't suspend parent when async child suspend_{noirq, late} fails to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: pm-sleep-don-t-suspend-parent-when-async-child-suspend_-noirq-late-fails.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 6f75c3fd56daf547d684127a7f83c283c3c160d1 Mon Sep 17 00:00:00 2001 From: Brian Norris Date: Wed, 9 Nov 2016 17:21:08 -0800 Subject: PM / sleep: don't suspend parent when async child suspend_{noirq, late} fails From: Brian Norris commit 6f75c3fd56daf547d684127a7f83c283c3c160d1 upstream. Consider two devices, A and B, where B is a child of A, and B utilizes asynchronous suspend (it does not matter whether A is sync or async). If B fails to suspend_noirq() or suspend_late(), or is interrupted by a wakeup (pm_wakeup_pending()), then it aborts and sets the async_error variable. However, device A does not (immediately) check the async_error variable; it may continue to run its own suspend_noirq()/suspend_late() callback. This is bad. We can resolve this problem by doing our error and wakeup checking (particularly, for the async_error flag) after waiting for children to suspend, instead of before. This also helps align the logic for the noirq and late suspend cases with the logic in __device_suspend(). It's easy to observe this erroneous behavior by, for example, forcing a device to sleep a bit in its suspend_noirq() (to ensure the parent is waiting for the child to complete), then return an error, and watch the parent suspend_noirq() still get called. (Or similarly, fake a wakeup event at the right (or is it wrong?) time.) Fixes: de377b397272 (PM / sleep: Asynchronous threads for suspend_late) Fixes: 28b6fd6e3779 (PM / sleep: Asynchronous threads for suspend_noirq) Reported-by: Jeffy Chen Signed-off-by: Brian Norris Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman --- drivers/base/power/main.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) --- a/drivers/base/power/main.c +++ b/drivers/base/power/main.c @@ -1022,6 +1022,8 @@ static int __device_suspend_noirq(struct TRACE_DEVICE(dev); TRACE_SUSPEND(0); + dpm_wait_for_children(dev, async); + if (async_error) goto Complete; @@ -1033,8 +1035,6 @@ static int __device_suspend_noirq(struct if (dev->power.syscore || dev->power.direct_complete) goto Complete; - dpm_wait_for_children(dev, async); - if (dev->pm_domain) { info = "noirq power domain "; callback = pm_noirq_op(&dev->pm_domain->ops, state); @@ -1169,6 +1169,8 @@ static int __device_suspend_late(struct __pm_runtime_disable(dev, false); + dpm_wait_for_children(dev, async); + if (async_error) goto Complete; @@ -1180,8 +1182,6 @@ static int __device_suspend_late(struct if (dev->power.syscore || dev->power.direct_complete) goto Complete; - dpm_wait_for_children(dev, async); - if (dev->pm_domain) { info = "late power domain "; callback = pm_late_early_op(&dev->pm_domain->ops, state); Patches currently in stable-queue which might be from briannorris@chromium.org are queue-4.4/pm-sleep-don-t-suspend-parent-when-async-child-suspend_-noirq-late-fails.patch