From 11b2dcefd88e8ae01a11c6df55d91206ac226c52 Mon Sep 17 00:00:00 2001 From: Brian Norris Date: Thu, 20 Oct 2016 12:09:30 +0800 Subject: [PATCH] FROMLIST: PM / sleep: don't suspend parent when async child suspend_{noirq,late} fails 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.) Change-Id: I9f6d9a599b45aaeb2debccc50a47525f138ad07e 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: Shawn Lin --- 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 d388edadfb6a..982f586e9290 100644 --- a/drivers/base/power/main.c +++ b/drivers/base/power/main.c @@ -1038,6 +1038,9 @@ 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); @@ -1185,6 +1188,9 @@ 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); -- 2.34.1