Re: [Xen-devel] [PATCH 15/15] xsm: add a default policy to .init.data

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 09/06/16 15:47, Daniel De Graaf wrote:
> diff --git a/xen/xsm/xsm_core.c b/xen/xsm/xsm_core.c
> index 4a264c2..6ffccb2 100644
> --- a/xen/xsm/xsm_core.c
> +++ b/xen/xsm/xsm_core.c
> @@ -36,6 +36,17 @@ static inline int verify(struct xsm_operations *ops)
>      return 0;
>  }
>  
> +extern char __xsm_init_policy_start[], __xsm_init_policy_end[];
> +
> +static void __init xsm_policy_init(void)
> +{
> +    if ( policy_size == 0 && __xsm_init_policy_end != 
> __xsm_init_policy_start )
> +    {
> +        policy_buffer = __xsm_init_policy_start;

I think this might cause a problem for ARM.

xsm_dt_init(void) does

ret = xsm_core_init();
xfree(policy_buffer);

which might now try freeing a piece of initdata.  Even going back to c/s
a8f2fb51c19 which introduced this code, I can't spot its justification.


It also looks like the entire policy buffer can be const, at which point
it can be linked slightly higher in .init.data with the other
logically-const data.

~Andrew

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