On Wed, Mar 24, 2021 at 10:52:30AM -0600, Rob Herring wrote:
> On Wed, Mar 24, 2021 at 9:04 AM Changbin Du <changbin.du@xxxxxxxxx> wrote:
> >
> > The setup_arch() would invoke unflatten_device_tree() even no
> > valid fdt found. So we'd better check it first and return early.
> >
> > Signed-off-by: Changbin Du <changbin.du@xxxxxxxxx>
> > ---
> > drivers/of/fdt.c | 5 +++++
> > 1 file changed, 5 insertions(+)
> >
> > diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
> > index dcc1dd96911a..05d439d63bc5 100644
> > --- a/drivers/of/fdt.c
> > +++ b/drivers/of/fdt.c
> > @@ -1225,6 +1225,11 @@ bool __init early_init_dt_scan(void *params)
> > */
> > void __init unflatten_device_tree(void)
> > {
> > + if (!initial_boot_params) {
> > + pr_warn("No valid device tree found, continuing without\n");
>
> How are you going to see this message if you have no DT?
>
This aligns to what unflatten_and_copy_device_tree() does.
> > + return;
>
> And the arch is supposed to just continue on oblivious that it has no DT?
>
As checking the arch code(arm, riscv), I suppose so.
> > + }
> > +
> > __unflatten_device_tree(initial_boot_params, NULL, &of_root,
> > early_init_dt_alloc_memory_arch, false);
>
> Soon as you get here with a NULL initial_boot_params, you'll get a
> backtrace and halt.
>
No, we have returned before.
> >
> > --
> > 2.30.2
> >
--
Cheers,
Changbin Du
