5.4-stable review patch. If anyone has any objections, please let me know.
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From: Rafael J. Wysocki rafael.j.wysocki@intel.com
[ Upstream commit f339f3541701d824a0256ad4bf14c26ceb6d79c3 ]
Currently, cpufreq_remove_dev() invokes the ->exit() driver callback without holding the policy rwsem which is inconsistent with what happens if ->exit() is invoked directly from cpufreq_offline().
It also manipulates the real_cpus mask and removes the CPU device symlink without holding the policy rwsem, but cpufreq_offline() holds the rwsem around the modifications thereof.
For consistency, modify cpufreq_remove_dev() to hold the policy rwsem until the ->exit() callback has been called (or it has been determined that it is not necessary to call it).
Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Acked-by: Viresh Kumar viresh.kumar@linaro.org Stable-dep-of: b8f85833c057 ("cpufreq: exit() callback is optional") Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/cpufreq/cpufreq.c | 21 ++++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-)
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 549788a2a9676..e727282f56963 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -1639,19 +1639,26 @@ static void cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif) if (!policy) return;
+ down_write(&policy->rwsem); + if (cpu_online(cpu)) - cpufreq_offline(cpu); + __cpufreq_offline(cpu, policy);
cpumask_clear_cpu(cpu, policy->real_cpus); remove_cpu_dev_symlink(policy, dev);
- if (cpumask_empty(policy->real_cpus)) { - /* We did light-weight exit earlier, do full tear down now */ - if (cpufreq_driver->offline) - cpufreq_driver->exit(policy); - - cpufreq_policy_free(policy); + if (!cpumask_empty(policy->real_cpus)) { + up_write(&policy->rwsem); + return; } + + /* We did light-weight exit earlier, do full tear down now */ + if (cpufreq_driver->offline) + cpufreq_driver->exit(policy); + + up_write(&policy->rwsem); + + cpufreq_policy_free(policy); }
/**