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authorXiongfeng Wang <wangxiongfeng2@huawei.com>2021-11-29 11:02:48 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2021-12-08 11:04:42 +0300
commitc649d47801df4c89c43125c8cf0a2ffdf2e7bbc1 (patch)
tree5dc71e3ce020db9b61a9b87f7b13889feea8fb05 /drivers/cpufreq
parentc4618188b15af986c4f43bb63271edc7d07f73aa (diff)
downloadlinux-c649d47801df4c89c43125c8cf0a2ffdf2e7bbc1.tar.xz
cpufreq: Fix get_cpu_device() failure in add_cpu_dev_symlink()
commit 2c1b5a84669d2477d8fffe9136e86a2cff591729 upstream. When I hot added a CPU, I found 'cpufreq' directory was not created below /sys/devices/system/cpu/cpuX/. It is because get_cpu_device() failed in add_cpu_dev_symlink(). cpufreq_add_dev() is the .add_dev callback of a CPU subsys interface. It will be called when the CPU device registered into the system. The call chain is as follows: register_cpu() ->device_register() ->device_add() ->bus_probe_device() ->cpufreq_add_dev() But only after the CPU device has been registered, we can get the CPU device by get_cpu_device(), otherwise it will return NULL. Since we already have the CPU device in cpufreq_add_dev(), pass it to add_cpu_dev_symlink(). I noticed that the 'kobj' of the CPU device has been added into the system before cpufreq_add_dev(). Fixes: 2f0ba790df51 ("cpufreq: Fix creation of symbolic links to policy directories") Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Cc: All applicable <stable@vger.kernel.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/cpufreq')
-rw-r--r--drivers/cpufreq/cpufreq.c9
1 files changed, 4 insertions, 5 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 284e940084c6..fcb44352623e 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1004,10 +1004,9 @@ static struct kobj_type ktype_cpufreq = {
.release = cpufreq_sysfs_release,
};
-static void add_cpu_dev_symlink(struct cpufreq_policy *policy, unsigned int cpu)
+static void add_cpu_dev_symlink(struct cpufreq_policy *policy, unsigned int cpu,
+ struct device *dev)
{
- struct device *dev = get_cpu_device(cpu);
-
if (unlikely(!dev))
return;
@@ -1391,7 +1390,7 @@ static int cpufreq_online(unsigned int cpu)
if (new_policy) {
for_each_cpu(j, policy->related_cpus) {
per_cpu(cpufreq_cpu_data, j) = policy;
- add_cpu_dev_symlink(policy, j);
+ add_cpu_dev_symlink(policy, j, get_cpu_device(j));
}
policy->min_freq_req = kzalloc(2 * sizeof(*policy->min_freq_req),
@@ -1565,7 +1564,7 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
/* Create sysfs link on CPU registration */
policy = per_cpu(cpufreq_cpu_data, cpu);
if (policy)
- add_cpu_dev_symlink(policy, cpu);
+ add_cpu_dev_symlink(policy, cpu, dev);
return 0;
}