Messages in this thread |  | | From | "Rafael J. Wysocki" <> | Subject | Re: [PATCH v2 2/2] PM / sleep: don't suspend parent when async child suspend_{noirq,late} fails | Date | Tue, 01 Nov 2016 05:25:39 +0100 |
| |
On Thursday, October 27, 2016 09:05:34 AM Brian Norris wrote: > 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 <jeffy.chen@rock-chips.com> > Signed-off-by: Brian Norris <briannorris@chromium.org> > Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> > --- > 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; > +
This is a second chech for async_error in this routine and is the first one really needed after adding this?
> 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; > +
Same question.
> if (dev->pm_domain) { > info = "late power domain "; > callback = pm_late_early_op(&dev->pm_domain->ops, state); >
Thanks, Rafael
|  |