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xen-devel
Re: [Xen-devel] [PATCH]Make sure processor_pminfo initialized before use
>>> On 08.09.11 at 08:09, "Zhang, Yang Z" <yang.z.zhang@xxxxxxxxx> wrote:
> Make sure processor_pminfo not null before use it
>
> If processor_pminfo not initialized, it will cause xen panic.
Mind pointing out what panic you observed, because ...
> Signed-off-by: Yang Zhang <yang.z.zhang@xxxxxxxxx>
>
> diff -r bdd19847ae63 xen/drivers/cpufreq/cpufreq.c
> --- a/xen/drivers/cpufreq/cpufreq.c Wed Sep 07 10:37:48 2011 +0100
> +++ b/xen/drivers/cpufreq/cpufreq.c Thu Sep 08 13:40:23 2011 +0800
> @@ -91,7 +91,7 @@ int __init cpufreq_register_governor(str
>
> int cpufreq_limit_change(unsigned int cpu)
> {
> - struct processor_performance *perf = &processor_pminfo[cpu]->perf;
> + struct processor_performance *perf;
... this (and all other changed instances below) is not actually
de-referencing processor_pminfo[cpu], and the first de-reference
always is only after that one got checked against NULL.
Jan
> struct cpufreq_policy *data;
> struct cpufreq_policy policy;
>
> @@ -99,6 +99,7 @@ int cpufreq_limit_change(unsigned int cp
> !processor_pminfo[cpu])
> return -ENODEV;
>
> + perf = &processor_pminfo[cpu]->perf;
> if (perf->platform_limit >= perf->state_count)
> return -EINVAL;
>
> @@ -120,12 +121,14 @@ int cpufreq_add_cpu(unsigned int cpu)
> struct cpufreq_dom *cpufreq_dom = NULL;
> struct cpufreq_policy new_policy;
> struct cpufreq_policy *policy;
> - struct processor_performance *perf = &processor_pminfo[cpu]->perf;
> + struct processor_performance *perf;
>
> /* to protect the case when Px was not controlled by xen */
> - if (!processor_pminfo[cpu] ||
> - !(perf->init & XEN_PX_INIT) ||
> - !cpu_online(cpu))
> + if (!processor_pminfo[cpu] || !cpu_online(cpu))
> + return -EINVAL;
> +
> + perf = &processor_pminfo[cpu]->perf;
> + if (!(perf->init & XEN_PX_INIT))
> return -EINVAL;
>
> if (!cpufreq_driver)
> @@ -261,12 +264,14 @@ int cpufreq_del_cpu(unsigned int cpu)
> struct list_head *pos;
> struct cpufreq_dom *cpufreq_dom = NULL;
> struct cpufreq_policy *policy;
> - struct processor_performance *perf = &processor_pminfo[cpu]->perf;
> + struct processor_performance *perf;
>
> /* to protect the case when Px was not controlled by xen */
> - if (!processor_pminfo[cpu] ||
> - !(perf->init & XEN_PX_INIT) ||
> - !cpu_online(cpu))
> + if (!processor_pminfo[cpu] || !cpu_online(cpu))
> + return -EINVAL;
> +
> + perf = &processor_pminfo[cpu]->perf;
> + if (!(perf->init & XEN_PX_INIT))
> return -EINVAL;
>
> if (!per_cpu(cpufreq_cpu_policy, cpu))
>
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-devel
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