On 15/06/2021 17.33, Steven Rostedt wrote:

On Tue, 15 Jun 2021 14:35:27 +0200
Rasmus Villemoes [off-list ref] wrote:

quoted

Reverting commit 3d5bfbd9716318b1ca5c38488aa69f64d38a9aa5 (gpio:
mpc8xxx: change the gpio interrupt flags.) makes it go away, as does
disabling CONFIG_PREEMPT_RT or simply booting a vanilla v5.10.42 (where
that option exists but cannot be selected).

I'm curious if it will also trigger on vanilla v5.10.42 but add to the
kernel command line: threadirqs

Make sure you have CONFIG_IRQ_FORCED_THREADING set too.

Because it appears to be an issue with that being called by the generic
threaded irq infrastructure, which PREEMPT_RT enables automatically.

It doesn't:

~ # uname -r
5.10.42-00001-g10216cf63a12
~ # grep -ow threadirqs /proc/cmdline
threadirqs
~ # zcat /proc/config.gz | grep FORCED_THREADING
CONFIG_IRQ_FORCED_THREADING=y
~ # dmesg | grep WARNING
~ #

(the one patch on top of 5.10.42 is a fixup of ls1021a.dtsi that I
should get upstream some day, but not something that should affect this
issue in any way).

Thanks for the suggestion.

Rasmus