linux-kernel - [PATCH] cpufreq: Stop BUGing the system

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Date:	Wed, 17 Dec 2014 09:51:35 -0600
From:	Nishanth Menon <nm@...com>
To:	Viresh Kumar <viresh.kumar@...aro.org>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>
CC:	<linux-kernel@...r.kernel.org>, <linux-pm@...r.kernel.org>,
	Nishanth Menon <nm@...com>
Subject: [PATCH] cpufreq: Stop BUGing the system

CPUFRreq subsystem is not a system catastrophic failure point.
Failures in these cases DONOT need complete system shutdown with BUG.
just refuse to let cpufreq function should be good enough.

Signed-off-by: Nishanth Menon <nm@...com>
---
 drivers/cpufreq/cpufreq.c |   17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index a09a29c..a5aa2fa 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -281,7 +281,10 @@ static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
 static void __cpufreq_notify_transition(struct cpufreq_policy *policy,
 		struct cpufreq_freqs *freqs, unsigned int state)
 {
-	BUG_ON(irqs_disabled());
+	if (irqs_disabled()) {
+		WARN(1, "IRQs disabled!\n");
+		return;
+	}
 
 	if (cpufreq_disabled())
 		return;
@@ -1253,9 +1256,12 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
 			/*
 			 * Reaching here after boot in a few seconds may not
 			 * mean that system will remain stable at "unknown"
-			 * frequency for longer duration. Hence, a BUG_ON().
+			 * frequency for longer duration. Hence, a WARN().
 			 */
-			BUG_ON(ret);
+			if (ret) {
+				WARN(1, "SYSTEM operating at invalid freq %u", policy->cur);
+				goto err_out_unregister;
+			}
 			pr_warn("%s: CPU%d: Unlisted initial frequency changed to: %u KHz\n",
 				__func__, policy->cpu, policy->cur);
 		}
@@ -2556,7 +2562,10 @@ static int __init cpufreq_core_init(void)
 		return -ENODEV;
 
 	cpufreq_global_kobject = kobject_create();
-	BUG_ON(!cpufreq_global_kobject);
+	if (!cpufreq_global_kobject) {
+		WARN(1, "No memory for cpufreq_global_kobject\n");
+		return -ENOMEM;
+	}
 
 	return 0;
 }
-- 
1.7.9.5

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