From 2a06839a786da086953064c26c713815675dfc8d Mon Sep 17 00:00:00 2001
From: Colin Ian King <colin.king@canonical.com>
Date: Tue, 5 Jan 2021 10:19:57 +0000
Subject: [PATCH] cpufreq: powernow-k8: pass policy rather than use
cpufreq_cpu_get()
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 <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>
---
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 0b5bf135b0907..59f16807921ad 100644
--- a/drivers/cpufreq/powernow-k8.c
+++ b/drivers/cpufreq/powernow-k8.c
@@ -887,9 +887,9 @@ 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;
@@ -921,9 +921,6 @@ 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);
@@ -978,7 +975,7 @@ 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");
--
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