[PATCH 5.17 348/772] Revert "cpufreq: Fix possible race in cpufreq online error path"

Greg Kroah-Hartman
2022-06-07T21:07:06Z

From: Viresh Kumar <viresh.kumar@linaro.org>

[ 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@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/cpufreq/cpufreq.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 233e8af48848..fbaa8e6c7d23 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1534,6 +1534,8 @@ 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);
@@ -1542,9 +1544,6 @@ 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;
--
2.35.1