This is a note to let you know that I've just added the patch titled
PM: EM: postpone creating the debugfs dir till fs_initcall
to the 5.10-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-em-postpone-creating-the-debugfs-dir-till-fs_init.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 8931f35582fbf8d89a47c6ddbcb25bccd546b102
Author: Lukasz Luba <lukasz.luba@xxxxxxx>
Date: Tue Mar 23 14:56:08 2021 +0000
PM: EM: postpone creating the debugfs dir till fs_initcall
[ Upstream commit fb9d62b27ab1e07d625591549c314b7d406d21df ]
The debugfs directory '/sys/kernel/debug/energy_model' is needed before
the Energy Model registration can happen. With the recent change in
debugfs subsystem it's not allowed to create this directory at early
stage (core_initcall). Thus creating this directory would fail.
Postpone the creation of the EM debug dir to later stage: fs_initcall.
It should be safe since all clients: CPUFreq drivers, Devfreq drivers
will be initialized in later stages.
The custom debug log below prints the time of creation the EM debug dir
at fs_initcall and successful registration of EMs at later stages.
[ 1.505717] energy_model: creating rootdir
[ 3.698307] cpu cpu0: EM: created perf domain
[ 3.709022] cpu cpu1: EM: created perf domain
Fixes: 56348560d495 ("debugfs: do not attempt to create a new file before the filesystem is initalized")
Reported-by: Ionela Voinescu <ionela.voinescu@xxxxxxx>
Signed-off-by: Lukasz Luba <lukasz.luba@xxxxxxx>
Reviewed-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/kernel/power/energy_model.c b/kernel/power/energy_model.c
index c1ff7fa030ab..994ca8353543 100644
--- a/kernel/power/energy_model.c
+++ b/kernel/power/energy_model.c
@@ -85,7 +85,7 @@ static int __init em_debug_init(void)
return 0;
}
-core_initcall(em_debug_init);
+fs_initcall(em_debug_init);
#else /* CONFIG_DEBUG_FS */
static void em_debug_create_pd(struct device *dev) {}
static void em_debug_remove_pd(struct device *dev) {}
