CVE-2026-23137

In the Linux kernel, the following vulnerability has been resolved:

of: unittest: Fix memory leak in unittestdataadd()

In unittestdataadd(), if ofresolvephandles() fails, the allocated unittest_data is not freed, leading to a memory leak.

Fix this by using scope-based cleanup helper _free(kfree) for automatic resource cleanup. This ensures unittestdata is automatically freed when it goes out of scope in error paths.

For the success path, use retainandnull_ptr() to transfer ownership of the memory to the device tree and prevent double freeing.