[PATCH] kho: fix child node parsing for debugfs in/sub_fdts

[Pratyush Yadav]

On Mon, Mar 09 2026, ranxiaokai627 at 163.com wrote:

> From: Ran Xiaokai <ran.xiaokai at zte.com.cn>
>
> Commit e0c1731f5d57 ("kho: adopt radix tree for preserved memory tracking")
> changed KHO_FDT_SUB_TREE_PROP_NAME from "fdt" to "preserved-data". However,
> kho debugfs code still hard-coded the "fdt" string when parsing the
> device tree, causing the debugfs node /debugfs/kho/in/sub_fdts/
> fail to parse child nodes correctly.
>
> Fix this by including the header file and using KHO_FDT_SUB_TREE_PROP_NAME
> instead of the hard-coded string.
>
> Fixes: e0c1731f5d57 ("kho: adopt radix tree for preserved memory tracking")
> Signed-off-by: Ran Xiaokai <ran.xiaokai at zte.com.cn>

Breno's patch [0] also fixes this, but I'd rather have this go through
hotfixes and get backported to stable, and Breno's series to build on
top of this.

[0] https://lore.kernel.org/linux-mm/20260309-kho-v8-4-c3abcf4ac750@debian.org/

Reviewed-by: Pratyush Yadav <pratyush at kernel.org>

> ---
>  kernel/liveupdate/kexec_handover_debugfs.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/liveupdate/kexec_handover_debugfs.c b/kernel/liveupdate/kexec_handover_debugfs.c
> index 3f395fbd978f..acf368222682 100644
> --- a/kernel/liveupdate/kexec_handover_debugfs.c
> +++ b/kernel/liveupdate/kexec_handover_debugfs.c
> @@ -13,6 +13,7 @@
>  #include <linux/io.h>
>  #include <linux/libfdt.h>
>  #include <linux/mm.h>
> +#include <linux/kho/abi/kexec_handover.h>
>  #include "kexec_handover_internal.h"
>  
>  static struct dentry *debugfs_root;
> @@ -121,7 +122,7 @@ __init void kho_in_debugfs_init(struct kho_debugfs *dbg, const void *fdt)
>  		const char *name = fdt_get_name(fdt, child, NULL);
>  		const u64 *fdt_phys;
>  
> -		fdt_phys = fdt_getprop(fdt, child, "fdt", &len);
> +		fdt_phys = fdt_getprop(fdt, child, KHO_FDT_SUB_TREE_PROP_NAME, &len);
>  		if (!fdt_phys)
>  			continue;
>  		if (len != sizeof(*fdt_phys)) {

-- 
Regards,
Pratyush Yadav