+ kho-fix-error-handling-in-kho_add_subtree.patch added to mm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: kho: fix error handling in kho_add_subtree()
has been added to the -mm mm-unstable branch.  Its filename is
     kho-fix-error-handling-in-kho_add_subtree.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/kho-fix-error-handling-in-kho_add_subtree.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Breno Leitao <leitao@debian.org>
Subject: kho: fix error handling in kho_add_subtree()
Date: Tue, 07 Apr 2026 10:01:47 -0700

Fix two error handling issues in kho_add_subtree(), where it doesn't
handle the error path correctly.

1. If fdt_setprop() fails after the subnode has been created, the
   subnode is not removed. This leaves an incomplete node in the FDT
   (missing "preserved-data" or "blob-size" properties).

2. The fdt_setprop() return value (an FDT error code) is stored
   directly in err and returned to the caller, which expects -errno.

Fix both by storing fdt_setprop() results in fdt_err, jumping to a new
out_del_node label that removes the subnode on failure, and only setting
err = 0 on the success path, otherwise returning -ENOMEM (instead of
FDT_ERR_ errors that would come from fdt_setprop).

Link: https://lkml.kernel.org/r/20260407-kho_fix_send-v1-1-b21977feb960@debian.org
Fixes: 3dc92c311498 ("kexec: add Kexec HandOver (KHO) generation helpers")
Signed-off-by: Breno Leitao <leitao@debian.org>
Suggested-by: Pratyush Yadav <pratyush@kernel.org>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Alexander Graf <graf@amazon.com>
Cc: Breno Leitao <leitao@debian.org>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 kernel/liveupdate/kexec_handover.c |   21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)

--- a/kernel/liveupdate/kexec_handover.c~kho-fix-error-handling-in-kho_add_subtree
+++ a/kernel/liveupdate/kexec_handover.c
@@ -762,19 +762,24 @@ int kho_add_subtree(const char *name, vo
 		goto out_pack;
 	}
 
-	err = fdt_setprop(root_fdt, off, KHO_SUB_TREE_PROP_NAME,
-			  &phys, sizeof(phys));
-	if (err < 0)
-		goto out_pack;
+	fdt_err = fdt_setprop(root_fdt, off, KHO_SUB_TREE_PROP_NAME,
+			      &phys, sizeof(phys));
+	if (fdt_err < 0)
+		goto out_del_node;
 
-	err = fdt_setprop(root_fdt, off, KHO_SUB_TREE_SIZE_PROP_NAME,
-			  &size_u64, sizeof(size_u64));
-	if (err < 0)
-		goto out_pack;
+	fdt_err = fdt_setprop(root_fdt, off, KHO_SUB_TREE_SIZE_PROP_NAME,
+			      &size_u64, sizeof(size_u64));
+	if (fdt_err < 0)
+		goto out_del_node;
 
 	WARN_ON_ONCE(kho_debugfs_blob_add(&kho_out.dbg, name, blob,
 					  size, false));
 
+	err = 0;
+	goto out_pack;
+
+out_del_node:
+	fdt_del_node(root_fdt, off);
 out_pack:
 	fdt_pack(root_fdt);
 
_

Patches currently in -mm which might be from leitao@debian.org are

mm-kmemleak-add-config_debug_kmemleak_verbose-build-option.patch
kho-add-size-parameter-to-kho_add_subtree.patch
kho-rename-fdt-parameter-to-blob-in-kho_add-remove_subtree.patch
kho-persist-blob-size-in-kho-fdt.patch
kho-fix-kho_in_debugfs_init-to-handle-non-fdt-blobs.patch
kho-kexec-metadata-track-previous-kernel-chain.patch
kho-kexec-metadata-track-previous-kernel-chain-fix.patch
kho-document-kexec-metadata-tracking-feature.patch
mm-vmstat-fix-vmstat_shepherd-double-scheduling-vmstat_update.patch
kho-fix-error-handling-in-kho_add_subtree.patch
mm-vmstat-spread-vmstat_update-requeue-across-the-stat-interval.patch