Re: [PATCH] of: fdt: skip KHO when booting as crash kernel

[Evangelos Petrongonas]

On Thu, Apr 09, 2026 at 05:22:11PM +0300 Mike Rapoport wrote:
> Hi Evangelos,
> 
> On Tue, Apr 07, 2026 at 03:06:33PM +0000, Evangelos Petrongonas wrote:
> What about x86? ;-)
>

Well... I was planning to reply with "we will sort it out in a followup".
I have a suspicion though, that you knew that the kho_fill_kimage()
approach would take care of it. Nice! Thanks for the tip.
I will post soon the v2.

> > diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
> > index 43a0944ca462..77018ec99fc8 100644
> > --- a/drivers/of/fdt.c
> > +++ b/drivers/of/fdt.c
> > @@ -926,6 +926,9 @@ static void __init early_init_dt_check_kho(void)
> >  	if (!IS_ENABLED(CONFIG_KEXEC_HANDOVER) || (long)node < 0)
> >  		return;
> >  
> > +	if (is_kdump_kernel())
> > +		return;
> > +
> 
> This seems redundant if don't add KHO nodes at the first place.
> 
Indeed it is, it was more of a defense in depth in case there were stale
data somehow, but I will drop it in v2.

> >  	if (!of_flat_dt_get_addr_size(node, "linux,kho-fdt",
> >  				      &fdt_start, &fdt_size))
> >  		return;
> > diff --git a/drivers/of/kexec.c b/drivers/of/kexec.c
> > index c4cf3552c018..b95f0b386684 100644
> > --- a/drivers/of/kexec.c
> > +++ b/drivers/of/kexec.c
> > @@ -271,7 +271,8 @@ static int kho_add_chosen(const struct kimage *image, void *fdt, int chosen_node
> >  	if (ret && ret != -FDT_ERR_NOTFOUND)
> >  		return ret;
> >  
> > -	if (!image->kho.fdt || !image->kho.scratch)
> > +	if (!image->kho.fdt || !image->kho.scratch ||
> > +	    image->type == KEXEC_TYPE_CRASH)
> >  		return 0;
> >  
> >  	fdt_mem = image->kho.fdt;
> 
> kho_add_chosen() bails out if there's no KHO buffer in kimage, so if
> kho_fill_kimage won't add KHO buffer to kexec_crash_image it should be
> enough.
> 
Indeed, one guard to rule them all. Much more elegant than the
"let's sprinkle checks everywhere (apart from x86))" approach.

> > -- 
> > 2.43.0
> > 
> > 
> > 
> > 
> > Amazon Web Services Development Center Germany GmbH
> > Tamara-Danz-Str. 13
> > 10243 Berlin
> > Geschaeftsfuehrung: Christof Hellmis, Andreas Stieger
> > Eingetragen am Amtsgericht Charlottenburg unter HRB 257764 B
> > Sitz: Berlin
> > Ust-ID: DE 365 538 597
> > 
> 
> -- 
> Sincerely yours,
> Mike.

Kind Regards,
Evangelos



Amazon Web Services Development Center Germany GmbH
Tamara-Danz-Str. 13
10243 Berlin
Geschaeftsfuehrung: Christof Hellmis, Andreas Stieger
Eingetragen am Amtsgericht Charlottenburg unter HRB 257764 B
Sitz: Berlin
Ust-ID: DE 365 538 597