[PATCH v8 4/6] kho: fix kho_in_debugfs_init() to handle non-FDT blobs

Breno Leitao
2026-03-09T13:42:42Z

kho_in_debugfs_init() has two problems when displaying incoming
sub-blobs in debugfs:

1. It uses the hardcoded property name "fdt" instead of
KHO_SUB_TREE_PROP_NAME ("preserved-data"), so it never finds
subtrees stored by the current kho_add_subtree().

2. It calls fdt_totalsize() to determine blob sizes, which assumes
all blobs are FDTs. This breaks for non-FDT blobs like struct
kho_kexec_metadata.

Fix both issues by using KHO_SUB_TREE_PROP_NAME to find subtrees
and reading the "blob-size" property from the FDT (persisted by
kho_add_subtree()) instead of calling fdt_totalsize().

Signed-off-by: Breno Leitao <leitao@debian.org>
---
kernel/liveupdate/kexec_handover_debugfs.c | 34 ++++++++++++++++++++----------
1 file changed, 23 insertions(+), 11 deletions(-)

diff --git a/kernel/liveupdate/kexec_handover_debugfs.c b/kernel/liveupdate/kexec_handover_debugfs.c
index 7a100f2bf3947..257ee8a52be66 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;
@@ -121,23 +122,34 @@ __init void kho_in_debugfs_init(struct kho_debugfs *dbg, const void *fdt)
fdt_for_each_subnode(child, fdt, 0) {
int len = 0;
const char *name = fdt_get_name(fdt, child, NULL);
- const u64 *fdt_phys;
- void *sub_fdt;
+ const u64 *blob_phys;
+ const u64 *blob_size;
+ void *blob;

- fdt_phys = fdt_getprop(fdt, child, "fdt", &len);
- if (!fdt_phys)
+ blob_phys = fdt_getprop(fdt, child,
+ KHO_SUB_TREE_PROP_NAME, &len);
+ if (!blob_phys)
continue;
- if (len != sizeof(*fdt_phys)) {
- pr_warn("node %s prop fdt has invalid length: %d\n",
- name, len);
+ if (len != sizeof(*blob_phys)) {
+ pr_warn("node %s prop %s has invalid length: %d\n",
+ name, KHO_SUB_TREE_PROP_NAME, len);
continue;
}
- sub_fdt = phys_to_virt(*fdt_phys);
+
+ blob_size = fdt_getprop(fdt, child,
+ KHO_SUB_TREE_SIZE_PROP_NAME, &len);
+ if (!blob_size || len != sizeof(*blob_size)) {
+ pr_warn("node %s missing or invalid %s property\n",
+ name, KHO_SUB_TREE_SIZE_PROP_NAME);
+ continue;
+ }
+
+ blob = phys_to_virt(*blob_phys);
err = __kho_debugfs_blob_add(&dbg->fdt_list, sub_fdt_dir, name,
- sub_fdt, fdt_totalsize(sub_fdt));
+ blob, *blob_size);
if (err) {
- pr_warn("failed to add fdt %s to debugfs: %pe\n", name,
- ERR_PTR(err));
+ pr_warn("failed to add blob %s to debugfs: %pe\n",
+ name, ERR_PTR(err));
continue;
}
}

--
2.47.3