This is a note to let you know that I've just added the patch titled
PM: runtime: Do not call __rpm_callback() from rpm_idle()
to the 5.4-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-runtime-do-not-call-__rpm_callback-from-rpm_idle.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 110aaedb4ee40899a36a273475b4e53795d06486
Author: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Date: Fri Dec 2 15:30:28 2022 +0100
PM: runtime: Do not call __rpm_callback() from rpm_idle()
[ Upstream commit bc80c2e438dcbfcf748452ec0f7ad5b79ff3ad88 ]
Calling __rpm_callback() from rpm_idle() after adding device links
support to the former is a clear mistake.
Not only it causes rpm_idle() to carry out unnecessary actions, but it
is also against the assumption regarding the stability of PM-runtime
status across __rpm_callback() invocations, because rpm_suspend() and
rpm_resume() may run in parallel with __rpm_callback() when it is called
by rpm_idle() and the device's PM-runtime status can be updated by any
of them.
Fixes: 21d5c57b3726 ("PM / runtime: Use device links")
Link: https://lore.kernel.org/linux-pm/36aed941-a73e-d937-2721-4f0decd61ce0@xxxxxxxxxxx
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Reviewed-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index 24a3013728c3..9ee58bf49d13 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -465,7 +465,17 @@ static int rpm_idle(struct device *dev, int rpmflags)
dev->power.idle_notification = true;
- retval = __rpm_callback(callback, dev);
+ if (dev->power.irq_safe)
+ spin_unlock(&dev->power.lock);
+ else
+ spin_unlock_irq(&dev->power.lock);
+
+ retval = callback(dev);
+
+ if (dev->power.irq_safe)
+ spin_lock(&dev->power.lock);
+ else
+ spin_lock_irq(&dev->power.lock);
dev->power.idle_notification = false;
wake_up_all(&dev->power.wait_queue);
