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| author | Tao Wang <kevin.wangtao@hisilicon.com> | 2018-05-26 10:16:48 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-06-26 02:54:02 +0300 |
| commit | 52e91680cbd42fc2de610d6432fa28a47ab2d402 (patch) | |
| tree | a01fa6d26c7dce89a924f2d8dc4117b270e17eb0 | |
| parent | d7b76de131b4598e0bb12d9da83a5e99b8deda30 (diff) | |
| download | linux-52e91680cbd42fc2de610d6432fa28a47ab2d402.tar.xz | |
cpufreq: Fix new policy initialization during limits updates via sysfs
commit c7d1f119c48f64bebf0fa1e326af577c6152fe30 upstream.
If the policy limits are updated via cpufreq_update_policy() and
subsequently via sysfs, the limits stored in user_policy may be
set incorrectly.
For example, if both min and max are set via sysfs to the maximum
available frequency, user_policy.min and user_policy.max will also
be the maximum. If a policy notifier triggered by
cpufreq_update_policy() lowers both the min and the max at this
point, that change is not reflected by the user_policy limits, so
if the max is updated again via sysfs to the same lower value,
then user_policy.max will be lower than user_policy.min which
shouldn't happen. In particular, if one of the policy CPUs is
then taken offline and back online, cpufreq_set_policy() will
fail for it due to a failing limits check.
To prevent that from happening, initialize the min and max fields
of the new_policy object to the ones stored in user_policy that
were previously set via sysfs.
Signed-off-by: Kevin Wangtao <kevin.wangtao@hisilicon.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Subject & changelog ]
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>
| -rw-r--r-- | drivers/cpufreq/cpufreq.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 8814c572e263..e8fa2fc43b75 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -703,6 +703,8 @@ static ssize_t store_##file_name \ struct cpufreq_policy new_policy; \ \ memcpy(&new_policy, policy, sizeof(*policy)); \ + new_policy.min = policy->user_policy.min; \ + new_policy.max = policy->user_policy.max; \ \ ret = sscanf(buf, "%u", &new_policy.object); \ if (ret != 1) \ |