[PATCH 4.9 15/25] cpufreq: powernow-k8: pass policy rather than use cpufreq_cpu_get()
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: 2021-01-15 13:08:09
Also in:
lkml
From: Colin Ian King <redacted>
commit 943bdd0cecad06da8392a33093230e30e501eccc 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: b43a7ffbf33b ("cpufreq: Notify all policy->cpus in cpufreq_notify_transition()")
Suggested-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Colin Ian King <redacted>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <redacted>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/cpufreq/powernow-k8.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)
--- a/drivers/cpufreq/powernow-k8.c
+++ b/drivers/cpufreq/powernow-k8.c@@ -887,9 +887,9 @@ static int get_transition_latency(struct /* 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;
@@ -921,9 +921,6 @@ static int transition_frequency_fidvid(s 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);
@@ -978,7 +975,7 @@ static long powernowk8_target_fn(void *a 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");