Please fix the subject as well :)
On 05-01-21, 10:11, Colin King wrote:
> From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
>
> 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@xxxxxxxxxxxxx>
> ---
>
> V2: pass the policy to transition_frequency_fidvid rather than add
> a null pointer check on the return from a cpufreq_cpu_get call.
> ---
> drivers/cpufreq/powernow-k8.c | 9 +++------
> 1 file changed, 3 insertions(+), 6 deletions(-)
>
> 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");
> --
> 2.29.2
--
viresh
