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cpufreq: powernow-k8: pass policy rather than use cpufreq_cpu_get() 

commit 943bdd0cec upstream.

Currently there is an unlikely case where cpufreq_cpu_get() returns a
NULL policy and this will cause a NULL pointer dereference later on.

Fix this by passing the policy to transition_frequency_fidvid() from
the caller and hence eliminating the need for the cpufreq_cpu_get()
and cpufreq_cpu_put().

Thanks to Viresh Kumar for suggesting the fix.

Addresses-Coverity: ("Dereference null return")
Fixes: b43a7ffbf3 ("cpufreq: Notify all policy->cpus in cpufreq_notify_transition()")
Suggested-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
5.4-rM2-2.2.x-imx-squashed
Colin Ian King 2021-01-05 10:19:57 +00:00 committed by Greg Kroah-Hartman
parent 4dd15f9bc8
commit 9ff4796e6f
1 changed files with 3 additions and 6 deletions
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9
drivers/cpufreq/powernow-k8.c
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@ -878,9 +878,9 @@ static int get_transition_latency(struct powernow_k8_data *data)
/* Take a frequency, and issue the fid/vid transition command */
static int transition_frequency_fidvid(struct powernow_k8_data *data,
unsigned int index)
unsigned int index,
struct cpufreq_policy *policy)
{
struct cpufreq_policy *policy;
u32 fid = 0;
u32 vid = 0;
int res;
@ -912,9 +912,6 @@ static int transition_frequency_fidvid(struct powernow_k8_data *data,
freqs.old = find_khz_freq_from_fid(data->currfid);
freqs.new = find_khz_freq_from_fid(fid);
policy = cpufreq_cpu_get(smp_processor_id());
cpufreq_cpu_put(policy);
cpufreq_freq_transition_begin(policy, &freqs);
res = transition_fid_vid(data, fid, vid);
cpufreq_freq_transition_end(policy, &freqs, res);
@ -969,7 +966,7 @@ static long powernowk8_target_fn(void *arg)
powernow_k8_acpi_pst_values(data, newstate);
ret = transition_frequency_fidvid(data, newstate);
ret = transition_frequency_fidvid(data, newstate, pol);
if (ret) {
pr_err("transition frequency failed\n");