| Message ID | 20210105101957.59072-1-colin.king@canonical.com (mailing list archive) |
|---|---|
| State | Mainlined, archived |
| Headers | show |
| Series | [V3] cpufreq: powernow-k8: pass policy rather than use cpufreq_cpu_get | expand |
On 05-01-21, 10:19, Colin King wrote: > From: Colin Ian King <colin.king@canonical.com> > > 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: b43a7ffbf33b ("cpufreq: Notify all policy->cpus in cpufreq_notify_transition()") > Signed-off-by: Colin Ian King <colin.king@canonical.com> > --- > > V2: pass the policy to transition_frequency_fidvid rather than add > a null pointer check on the return from a cpufreq_cpu_get call. > V3: update subject line to match the fix > > --- > drivers/cpufreq/powernow-k8.c | 9 +++------ > 1 file changed, 3 insertions(+), 6 deletions(-) Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
On Tue, Jan 5, 2021 at 11:22 AM Viresh Kumar <viresh.kumar@linaro.org> wrote: > > On 05-01-21, 10:19, Colin King wrote: > > From: Colin Ian King <colin.king@canonical.com> > > > > 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: b43a7ffbf33b ("cpufreq: Notify all policy->cpus in cpufreq_notify_transition()") > > Signed-off-by: Colin Ian King <colin.king@canonical.com> > > --- > > > > V2: pass the policy to transition_frequency_fidvid rather than add > > a null pointer check on the return from a cpufreq_cpu_get call. > > V3: update subject line to match the fix > > > > --- > > drivers/cpufreq/powernow-k8.c | 9 +++------ > > 1 file changed, 3 insertions(+), 6 deletions(-) > > Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Applied as 5.11-rc material, thanks!
diff --git a/drivers/cpufreq/powernow-k8.c b/drivers/cpufreq/powernow-k8.c index 0acc9e241cd7..b9ccb6a3dad9 100644 --- a/drivers/cpufreq/powernow-k8.c +++ b/drivers/cpufreq/powernow-k8.c @@ -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");