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

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 <redacted>
Cc: Bjorn Andersson <redacted>
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;
 	}
 

---
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;
  	}