On Mon, 2023-03-06 at 15:33 -0600, Nathan Lynch via B4 Relay wrote:
> From: Nathan Lynch <nath...@linux.ibm.com>
>
> Any caller of rtas_call_unlocked() must provide an rtas_args
> parameter
> block distinct from the core rtas_args buffer used by the rtas_call()
> path. It's an unlikely error to make, but the potential consequences
> are grim, and it's trivial to check.
>
> Signed-off-by: Nathan Lynch <nath...@linux.ibm.com>
call_rtas_display_status() seems to do exactly this, or am I missing
something?
> ---
> arch/powerpc/kernel/rtas.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c
> index 633c925164e7..47a2aa43d7d4 100644
> --- a/arch/powerpc/kernel/rtas.c
> +++ b/arch/powerpc/kernel/rtas.c
> @@ -1042,6 +1042,13 @@ void rtas_call_unlocked(struct rtas_args
> *args, int token, int nargs, int nret,
> {
> va_list list;
>
> + /*
> + * Callers must not use rtas_args; otherwise they risk
> + * corrupting the state of the rtas_call() path, which is
> + * serialized by rtas_lock.
> + */
> + WARN_ON(args == &rtas_args);
> +
> va_start(list, nret);
> va_rtas_call(args, token, nargs, nret, list);
> va_end(list);
>
--
Andrew Donnellan OzLabs, ADL Canberra
a...@linux.ibm.com IBM Australia Limited
