From mboxrd@z Thu Jan 1 00:00:00 1970 From: Brian Norris Subject: [PATCH v2 2/2] PM / sleep: don't suspend parent when async child suspend_{noirq,late} fails Date: Thu, 27 Oct 2016 09:05:34 -0700 Message-ID: <1477584334-39956-1-git-send-email-briannorris@chromium.org> References: <1476923170-111986-2-git-send-email-briannorris@chromium.org> Return-path: Received: from mail-pf0-f174.google.com ([209.85.192.174]:36835 "EHLO mail-pf0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S942012AbcJ0QFu (ORCPT ); Thu, 27 Oct 2016 12:05:50 -0400 Received: by mail-pf0-f174.google.com with SMTP id e6so20334511pfk.3 for ; Thu, 27 Oct 2016 09:05:50 -0700 (PDT) In-Reply-To: <1476923170-111986-2-git-send-email-briannorris@chromium.org> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: "Rafael J . Wysocki" , Pavel Machek , Len Brown , Greg Kroah-Hartman Cc: linux-kernel@vger.kernel.org, Doug Anderson , Brian Norris , Jeffy Chen , linux-pm@vger.kernel.org, Chuansheng Liu , Dmitry Torokhov , Brian Norris 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 checking the async_error flag after waiting for children to suspend, using the same logic for the noirq and late suspend cases as we already do for __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 Reviewed-by: Dmitry Torokhov --- v2: s/early/late/ in commit message drivers/base/power/main.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c index c58563581345..eaf6b53463a5 100644 --- a/drivers/base/power/main.c +++ b/drivers/base/power/main.c @@ -1040,6 +1040,9 @@ static int __device_suspend_noirq(struct device *dev, pm_message_t state, bool a dpm_wait_for_children(dev, async); + if (async_error) + goto Complete; + if (dev->pm_domain) { info = "noirq power domain "; callback = pm_noirq_op(&dev->pm_domain->ops, state); @@ -1187,6 +1190,9 @@ static int __device_suspend_late(struct device *dev, pm_message_t state, bool as dpm_wait_for_children(dev, async); + if (async_error) + goto Complete; + if (dev->pm_domain) { info = "late power domain "; callback = pm_late_early_op(&dev->pm_domain->ops, state); -- 2.8.0.rc3.226.g39d4020