Re: BUG: unable to handle kernel NULL pointer dereference at 00000002

[Frederik Deweerdt <deweerdt@free.fr>]

Hello  Aneesh,

On Fri, Jul 25, 2008 at 03:23:17PM +0530, Aneesh Kumar K.V wrote:
> [  163.378265] BUG: unable to handle kernel NULL pointer dereference at 00000002
> [  163.378276] IP: [<c0124933>] sched_power_savings_store+0x13/0x70

Does the attached patch solve the problem?

Regards,
Frederik

diff --git a/kernel/sched.c b/kernel/sched.c
index 0047bd9..090b397 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -7643,34 +7643,30 @@ static ssize_t sched_power_savings_store(const char *buf, size_t count, int smt)
 }
 
 #ifdef CONFIG_SCHED_MC
-static ssize_t sched_mc_power_savings_show(struct sys_device *dev,
-				struct sysdev_attribute *attr, char *page)
+static ssize_t sched_mc_power_savings_show(struct sysdev_class *cls, char *page)
 {
 	return sprintf(page, "%u\n", sched_mc_power_savings);
 }
-static ssize_t sched_mc_power_savings_store(struct sys_device *dev,
-					    struct sysdev_attribute *attr,
+static ssize_t sched_mc_power_savings_store(struct sysdev_class *cls,
 					    const char *buf, size_t count)
 {
 	return sched_power_savings_store(buf, count, 0);
 }
-static SYSDEV_ATTR(sched_mc_power_savings, 0644, sched_mc_power_savings_show,
+static SYSDEV_CLASS_ATTR(sched_mc_power_savings, 0644, sched_mc_power_savings_show,
 		   sched_mc_power_savings_store);
 #endif
 
 #ifdef CONFIG_SCHED_SMT
-static ssize_t sched_smt_power_savings_show(struct sys_device *dev,
-				struct sysdev_attribute *attr, char *page)
+static ssize_t sched_smt_power_savings_show(struct sysdev_class *cls, char *page)
 {
 	return sprintf(page, "%u\n", sched_smt_power_savings);
 }
-static ssize_t sched_smt_power_savings_store(struct sys_device *dev,
-					     struct sysdev_attribute *attr,
+static ssize_t sched_smt_power_savings_store(struct sysdev_class *cls,
 					     const char *buf, size_t count)
 {
 	return sched_power_savings_store(buf, count, 1);
 }
-static SYSDEV_ATTR(sched_smt_power_savings, 0644, sched_smt_power_savings_show,
+static SYSDEV_CLASS_ATTR(sched_smt_power_savings, 0644, sched_smt_power_savings_show,
 		   sched_smt_power_savings_store);
 #endif
 
@@ -7680,13 +7676,13 @@ int sched_create_sysfs_power_savings_entries(struct sysdev_class *cls)
 
 #ifdef CONFIG_SCHED_SMT
 	if (smt_capable())
-		err = sysfs_create_file(&cls->kset.kobj,
-					&attr_sched_smt_power_savings.attr);
+		err = sysdev_class_create_file(cls,
+					       &attr_sched_smt_power_savings);
 #endif
 #ifdef CONFIG_SCHED_MC
 	if (!err && mc_capable())
-		err = sysfs_create_file(&cls->kset.kobj,
-					&attr_sched_mc_power_savings.attr);
+		err = sysdev_class_create_file(cls,
+					       &attr_sched_mc_power_savings);
 #endif
 	return err;
 }