Re: BUG: unable to handle kernel NULL pointer dereference at00000002

From: Mike Galbraith
Date: Tue Jul 29 2008 - 00:22:37 EST


On Tue, 2008-07-29 at 00:26 +0200, Frederik Deweerdt wrote:
> 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?

Patch seems to have missed the boat for rc1 too.

>
> 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;
> }


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