Re: [kvm-unit-tests PATCH] powerpc: Fix endless loop that occurs without a device tree

[Laurent Vivier <lvivier@redhat.com>]

On 30/05/2017 17:07, Thomas Huth wrote:
> When running a powerpc kvm-unit-test, and there is accidentially
> no device tree available, the test ends up in an endless loop,
> spamming the console with "rtas_node: /rtas: FDT_ERR_BADMAGIC"
> messages: Somewhere the code calls abort() due to the missing
> device tree, and abort() calls exit() which in turn tries to
> shut down the VM with rtas_power_off(). rtas_power_off() needs
> the device tree again to look up the right RTAS token and we
> then end up in the next iteration.
> Fix it by adding some proper checks to rtas_power_off() and
> rtas_token().
> 
> Signed-off-by: Thomas Huth <thuth@redhat.com>
> ---
>  lib/powerpc/rtas.c | 13 ++++++++++++-
>  1 file changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/lib/powerpc/rtas.c b/lib/powerpc/rtas.c
> index 3407e25..a1c560b 100644
> --- a/lib/powerpc/rtas.c
> +++ b/lib/powerpc/rtas.c
> @@ -74,6 +74,9 @@ int rtas_token(const char *service)
>  	const struct fdt_property *prop;
>  	u32 *token;
>  
> +	if (!dt_available())
> +		return RTAS_UNKNOWN_SERVICE;
> +
>  	prop = fdt_get_property(dt_fdt(), rtas_node(), service, NULL);
>  	if (prop) {
>  		token = (u32 *)prop->data;
> @@ -116,6 +119,14 @@ int rtas_call(int token, int nargs, int nret, int *outputs, ...)
>  
>  void rtas_power_off(void)
>  {
> -	int ret = rtas_call(rtas_token("power-off"), 2, 1, NULL, -1, -1);
> +	int token, ret;
> +
> +	token = rtas_token("power-off");
> +	if (token < 0) {
> +		puts("RTAS power-off not available\n");
> +		return;
> +	}
> +
> +	ret = rtas_call(token, 2, 1, NULL, -1, -1);
>  	printf("RTAS power-off returned %d\n", ret);
>  }
> 
Reviewed-by: Laurent Vivier <lvivier@redhat.com>