From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-Id: <20120411231025.387614571@linuxfoundation.org> Date: Wed, 11 Apr 2012 16:11:00 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Alan Stern , "Rafael J. Wysocki" Subject: [ 42/78] PM / Runtime: dont forget to wake up waitqueue on failure In-Reply-To: <20120411231102.GA6404@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.3-stable review patch. If anyone has any objections, please let me know. ------------------ From: Alan Stern commit f2791d733a2f06997b573d1a3cfde21e6f529826 upstream. This patch (as1535) fixes a bug in the runtime PM core. When a runtime suspend attempt completes, whether successfully or not, the device's power.wait_queue is supposed to be signalled. But this doesn't happen in the failure pathway of rpm_suspend() when another autosuspend attempt is rescheduled. As a result, a task can get stuck indefinitely on the wait queue (I have seen this happen in testing). The patch fixes the problem by moving the wake_up_all() call up near the start of the failure code. Signed-off-by: Alan Stern Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman --- drivers/base/power/runtime.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/base/power/runtime.c +++ b/drivers/base/power/runtime.c @@ -532,6 +532,8 @@ static int rpm_suspend(struct device *de dev->power.suspend_time = ktime_set(0, 0); dev->power.max_time_suspended_ns = -1; dev->power.deferred_resume = false; + wake_up_all(&dev->power.wait_queue); + if (retval == -EAGAIN || retval == -EBUSY) { dev->power.runtime_error = 0; @@ -547,7 +549,6 @@ static int rpm_suspend(struct device *de } else { pm_runtime_cancel_pending(dev); } - wake_up_all(&dev->power.wait_queue); goto out; }