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authorTao Wang <kevin.wangtao@hisilicon.com>2018-05-26 15:16:48 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-06-26 08:08:08 +0800
commit5930589d3f85484611a9084169c8e86a8c183284 (patch)
parenta6c9a62e0f9f0153ea5f0a2a8d4879b3bafe096a (diff)
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>
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 7523929becdc..af5eff6835a8 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -657,6 +657,8 @@ 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) \