Re: [PATCH 1/3] xen/livepatch: simplify and unify logic in prepare_payload()

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 20/09/2024 11:36 am, Roger Pau Monne wrote:
> diff --git a/xen/common/livepatch.c b/xen/common/livepatch.c
> index d93a556bcda2..cea47ffe4c84 100644
> --- a/xen/common/livepatch.c
> +++ b/xen/common/livepatch.c
> @@ -647,15 +647,37 @@ static inline int livepatch_check_expectations(const 
> struct payload *payload)
>      nhooks = __sec->sec->sh_size / sizeof(*hook);                            
>              \
>  } while (0)
>  
> +static int fetch_buildid(const struct livepatch_elf_sec *sec,
> +                         struct livepatch_build_id *id)

Is this really fetch?  I'd describe it as parse, more than fetch.

> +{
> +    const Elf_Note *n = sec->load_addr;
> +    int rc;
> +
> +    ASSERT(sec);

This needs to turn back into a runtime check.  Now, if a livepatch is
missing one of the sections, we'll dereference NULL below, rather than
leaving no data in the struct livepatch_build_id.

~Andrew