linux-kernel - [PATCH 4.9 073/139] cpufreq: powernv: Fix frame-size-overflow in powernv_cpufreq_reboot

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Date:   Tue, 27 Oct 2020 14:49:27 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Srikar Dronamraju <srikar@...ux.vnet.ibm.com>,
        Daniel Axtens <dja@...ens.net>,
        Michael Ellerman <mpe@...erman.id.au>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.9 073/139] cpufreq: powernv: Fix frame-size-overflow in powernv_cpufreq_reboot_notifier

From: Srikar Dronamraju <srikar@...ux.vnet.ibm.com>

[ Upstream commit a2d0230b91f7e23ceb5d8fb6a9799f30517ec33a ]

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

  drivers/cpufreq/powernv-cpufreq.c: In function powernv_cpufreq_reboot_notifier:
  drivers/cpufreq/powernv-cpufreq.c:906:1: error: the frame size of 2064 bytes is larger than 2048 bytes

Fixes: cf30af76 ("cpufreq: powernv: Set the cpus to nominal frequency during reboot/kexec")
Signed-off-by: Srikar Dronamraju <srikar@...ux.vnet.ibm.com>
Reviewed-by: Daniel Axtens <dja@...ens.net>
Signed-off-by: Michael Ellerman <mpe@...erman.id.au>
Link: https://lore.kernel.org/r/20200922080254.41497-1-srikar@linux.vnet.ibm.com
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/cpufreq/powernv-cpufreq.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/cpufreq/powernv-cpufreq.c b/drivers/cpufreq/powernv-cpufreq.c
index c3b05676e0dbe..8d18264794252 100644
--- a/drivers/cpufreq/powernv-cpufreq.c
+++ b/drivers/cpufreq/powernv-cpufreq.c
@@ -784,12 +784,15 @@ static int powernv_cpufreq_reboot_notifier(struct notifier_block *nb,
 				unsigned long action, void *unused)
 {
 	int cpu;
-	struct cpufreq_policy cpu_policy;
+	struct cpufreq_policy *cpu_policy;
 
 	rebooting = true;
 	for_each_online_cpu(cpu) {
-		cpufreq_get_policy(&cpu_policy, cpu);
-		powernv_cpufreq_target_index(&cpu_policy, get_nominal_index());
+		cpu_policy = cpufreq_cpu_get(cpu);
+		if (!cpu_policy)
+			continue;
+		powernv_cpufreq_target_index(cpu_policy, get_nominal_index());
+		cpufreq_cpu_put(cpu_policy);
 	}
 
 	return NOTIFY_DONE;
-- 
2.25.1