Re: [Xen-devel] [PATCH 3/3] xen/arm: vgic-v3-its: Make vgic_v3_its_free_domain idempotent

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Tue, 4 Sep 2018, Julien Grall wrote:
> vgic_v3_its_free_domain may be called before vgic_v3_its_init_domain if
> the vGIC was failing to initalize itself. This means the list would be
> unitialized and result in a crash.
> 
> Thankfully, we only allow ITS for the hardware domain. So the crash is
> not a security issue. Fix it by checking whether the list the NULL.
> 
> Signed-off-by: Julien Grall <julien.grall@xxxxxxx>

Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>


> ---
> 
> Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> ---
>  xen/arch/arm/vgic-v3-its.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/xen/arch/arm/vgic-v3-its.c b/xen/arch/arm/vgic-v3-its.c
> index 32061c6b03..9edd97c4e7 100644
> --- a/xen/arch/arm/vgic-v3-its.c
> +++ b/xen/arch/arm/vgic-v3-its.c
> @@ -1548,6 +1548,10 @@ void vgic_v3_its_free_domain(struct domain *d)
>  {
>      struct virt_its *pos, *temp;
>  
> +    /* Cope with unitialized vITS */
> +    if ( list_head_is_null(&d->arch.vgic.vits_list) )
> +        return;
> +
>      list_for_each_entry_safe( pos, temp, &d->arch.vgic.vits_list, vits_list )
>      {
>          list_del(&pos->vits_list);
> -- 
> 2.11.0
> 

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