linux-kernel - [PATCH] cpufreq: powernv: Fix frame-size-overflow in powernv_cpufreq_work

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Message-Id: <20200316135743.57735-1-psampat@linux.ibm.com>
Date:   Mon, 16 Mar 2020 19:27:43 +0530
From:   Pratik Rajesh Sampat <psampat@...ux.ibm.com>
To:     linux-pm@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
        linux-kernel@...r.kernel.org, psampat@...ux.ibm.com,
        pratik.r.sampat@...il.com, ego@...ux.vnet.ibm.com, dja@...ens.net
Subject: [PATCH] cpufreq: powernv: Fix frame-size-overflow in powernv_cpufreq_work_fn

The patch avoids allocating cpufreq_policy on stack hence fixing frame
size overflow in 'powernv_cpufreq_work_fn'

Fixes: 227942809b52 ("cpufreq: powernv: Restore cpu frequency to policy->cur on unthrottling")
Signed-off-by: Pratik Rajesh Sampat <psampat@...ux.ibm.com>
---
 drivers/cpufreq/powernv-cpufreq.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/drivers/cpufreq/powernv-cpufreq.c b/drivers/cpufreq/powernv-cpufreq.c
index 56f4bc0d209e..20ee0661555a 100644
--- a/drivers/cpufreq/powernv-cpufreq.c
+++ b/drivers/cpufreq/powernv-cpufreq.c
@@ -902,6 +902,7 @@ static struct notifier_block powernv_cpufreq_reboot_nb = {
 void powernv_cpufreq_work_fn(struct work_struct *work)
 {
 	struct chip *chip = container_of(work, struct chip, throttle);
+	struct cpufreq_policy *policy;
 	unsigned int cpu;
 	cpumask_t mask;
 
@@ -916,12 +917,14 @@ void powernv_cpufreq_work_fn(struct work_struct *work)
 	chip->restore = false;
 	for_each_cpu(cpu, &mask) {
 		int index;
-		struct cpufreq_policy policy;
 
-		cpufreq_get_policy(&policy, cpu);
-		index = cpufreq_table_find_index_c(&policy, policy.cur);
-		powernv_cpufreq_target_index(&policy, index);
-		cpumask_andnot(&mask, &mask, policy.cpus);
+		policy = cpufreq_cpu_get(cpu);
+		if (!policy)
+			continue;
+		index = cpufreq_table_find_index_c(policy, policy->cur);
+		powernv_cpufreq_target_index(policy, index);
+		cpumask_andnot(&mask, &mask, policy->cpus);
+		cpufreq_cpu_put(policy);
 	}
 out:
 	put_online_cpus();
-- 
2.24.1