Re: [Xen-devel] [PATCH 1/2] Fix sched_priv corruption in ARINC653 alloc_vdata.

[George Dunlap <george.dunlap@xxxxxxxxxxxxx>]

On 31/10/13 20:47, Nathan Studer wrote:
> From: Nathan Studer <nate.studer@xxxxxxxxxxxxxxx>
>
> The ARINC653 scheduler was directly assigning and manipulating
> the sched_priv field of a vcpu in its alloc_vdata function.
>
> When creating a cpu pool, this resulted in the corruption
> of the sched_priv field of the vcpu, which was then passed
> to the initial scheduler's free_vdata function with
> disastrous results.
>
> Signed-off-by: Nathan Studer <nate.studer@xxxxxxxxxxxxxxx>
Reviewed-by: George Dunlap <george.dunlap@xxxxxxxxxxxxx>

> ---
>   xen/common/sched_arinc653.c |   15 +++++++++------
>   1 file changed, 9 insertions(+), 6 deletions(-)
>
> diff --git a/xen/common/sched_arinc653.c b/xen/common/sched_arinc653.c
> index 2502192..a1d9443 100644
> --- a/xen/common/sched_arinc653.c
> +++ b/xen/common/sched_arinc653.c
> @@ -380,11 +380,14 @@ a653sched_deinit(const struct scheduler *ops)
>   static void *
>   a653sched_alloc_vdata(const struct scheduler *ops, struct vcpu *vc, void *dd)
>   {
> +    arinc653_vcpu_t *svc;
> +
>       /*
>        * Allocate memory for the ARINC 653-specific scheduler data information
>        * associated with the given VCPU (vc).
> -     */
> -    if ( (vc->sched_priv = xmalloc(arinc653_vcpu_t)) == NULL )
> +     */
> +    svc = xmalloc(arinc653_vcpu_t);
> +    if ( svc == NULL )
>           return NULL;
>   
>       /*
> @@ -393,13 +396,13 @@ a653sched_alloc_vdata(const struct scheduler *ops, struct 
> vcpu *vc, void *dd)
>        * will call the vcpu_wake scheduler callback function and our scheduler
>        * will mark the VCPU awake.
>        */
> -    AVCPU(vc)->vc = vc;
> -    AVCPU(vc)->awake = 0;
> +    svc->vc = vc;
> +    svc->awake = 0;
>       if ( !is_idle_vcpu(vc) )
> -        list_add(&AVCPU(vc)->list, &SCHED_PRIV(ops)->vcpu_list);
> +        list_add(&svc->list, &SCHED_PRIV(ops)->vcpu_list);
>       update_schedule_vcpus(ops);
>   
> -    return AVCPU(vc);
> +    return svc;
>   }
>   
>   /**

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