[PATCH] cpufreq: qcom-cpufreq-hw: Avoid stack buffer for IRQ name

[Ard Biesheuvel <ardb@kernel.org>]

Registering an IRQ requires the string buffer containing the name to
remain allocated, as the name is not copied into another buffer.

So let's add a irq_name field to the data struct instead, which is
guaranteed to have the appropriate lifetime.

Cc: Thara Gopinath <thara.gopinath@linaro.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Andy Gross <agross@kernel.org>
Cc: linux-arm-msm@vger.kernel.org
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
I'm not following msm development closely, so apologies if this was
already fixed, or if this is not based on the right tree.

This fixes a crash on my Yoga C630 when reading /proc/interrupts.

 drivers/cpufreq/qcom-cpufreq-hw.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/cpufreq/qcom-cpufreq-hw.c b/drivers/cpufreq/qcom-cpufreq-hw.c
index 3cc27d9e2ed1..6613228fe68c 100644
--- a/drivers/cpufreq/qcom-cpufreq-hw.c
+++ b/drivers/cpufreq/qcom-cpufreq-hw.c
@@ -44,6 +44,7 @@ struct qcom_cpufreq_data {
 	/* Lock to synchronize between de-init sequence and re-starting LMh polling/interrupts */
 	spinlock_t throttle_lock;
 	int throttle_irq;
+	char irq_name[15];
 	bool cancel_throttle;
 };
 
@@ -371,7 +372,6 @@ static int qcom_cpufreq_hw_lmh_init(struct cpufreq_policy *policy, int index)
 {
 	struct qcom_cpufreq_data *data = policy->driver_data;
 	struct platform_device *pdev = cpufreq_get_driver_data();
-	char irq_name[15];
 	int ret;
 
 	/*
@@ -388,11 +388,11 @@ static int qcom_cpufreq_hw_lmh_init(struct cpufreq_policy *policy, int index)
 	spin_lock_init(&data->throttle_lock);
 	INIT_DEFERRABLE_WORK(&data->throttle_work, qcom_lmh_dcvs_poll);
 
-	snprintf(irq_name, sizeof(irq_name), "dcvsh-irq-%u", policy->cpu);
+	snprintf(data->irq_name, sizeof(data->irq_name), "dcvsh-irq-%u", policy->cpu);
 	ret = request_threaded_irq(data->throttle_irq, NULL, qcom_lmh_dcvs_handle_irq,
-				   IRQF_ONESHOT, irq_name, data);
+				   IRQF_ONESHOT, data->irq_name, data);
 	if (ret) {
-		dev_err(&pdev->dev, "Error registering %s: %d\n", irq_name, ret);
+		dev_err(&pdev->dev, "Error registering %s: %d\n", data->irq_name, ret);
 		return 0;
 	}
 
-- 
2.30.2