This is a note to let you know that I've just added the patch titled
Revert "cpufreq: Fix possible race in cpufreq online error path"
to the 5.15-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:
revert-cpufreq-fix-possible-race-in-cpufreq-online-e.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 525b633fe9454cb1c84df985da02d97614d6dc72
Author: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
Date: Mon May 9 09:27:37 2022 +0530
Revert "cpufreq: Fix possible race in cpufreq online error path"
[ Upstream commit 85f0e42bd65d01b351d561efb38e584d4c596553 ]
This reverts commit f346e96267cd76175d6c201b40f770c0116a8a04.
The commit tried to fix a possible real bug but it made it even worse.
The fix was simply buggy as now an error out to out_offline_policy or
out_exit_policy will try to release a semaphore which was never taken in
the first place. This works fine only if we failed late, i.e. via
out_destroy_policy.
Fixes: f346e96267cd ("cpufreq: Fix possible race in cpufreq online error path")
Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 502245710ee0..cddf7e13c232 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1528,6 +1528,8 @@ static int cpufreq_online(unsigned int cpu)
for_each_cpu(j, policy->real_cpus)
remove_cpu_dev_symlink(policy, get_cpu_device(j));
+ up_write(&policy->rwsem);
+
out_offline_policy:
if (cpufreq_driver->offline)
cpufreq_driver->offline(policy);
@@ -1536,9 +1538,6 @@ static int cpufreq_online(unsigned int cpu)
if (cpufreq_driver->exit)
cpufreq_driver->exit(policy);
- cpumask_clear(policy->cpus);
- up_write(&policy->rwsem);
-
out_free_policy:
cpufreq_policy_free(policy);
return ret;
