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Commit 8b471834 authored by Colin Ian King's avatar Colin Ian King Committed by Greg Kroah-Hartman
Browse files

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: b43a7ffb ("cpufreq: Notify all policy->cpus in cpufreq_notify_transition()")
Suggested-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: default avatarColin Ian King <colin.king@canonical.com>
Acked-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 1bf68c17

drivers/cpufreq/powernow-k8.c

+3 −6
Original line number Diff line number Diff line
@@ -881,9 +881,9 @@ 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;
@@ -915,9 +915,6 @@ 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);
@@ -972,7 +969,7 @@ 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");