Re: [PATCH 3/4] create-diff-object: don't include symbols for .livepatch.hooks.* sections

[Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>]

On Thu, Nov 7, 2024 at 3:15 PM Roger Pau Monne <roger.pau@xxxxxxxxxx> wrote:
>
> Not all toolchains generate symbols for the .livepatch.hooks.* sections,
> neither those symbols are required by the livepatch loading logic in Xen to
> find and process the hooks.  Hooks in livepatch payloads are found and
> processed based exclusively on section data.
>
> The unconditional attempt to expect each hook serction to have a matching
> symbol leads to a segmentation fault in create-diff-object when such symbol is
> not present, as the code references a NULL pointer.
>
> Fix this by not attempting to include symbols associated with hook sections.
>
> Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
> ---
>  create-diff-object.c | 2 --
>  1 file changed, 2 deletions(-)
>
> diff --git a/create-diff-object.c b/create-diff-object.c
> index d8a2afbf2774..924059a1842b 100644
> --- a/create-diff-object.c
> +++ b/create-diff-object.c
> @@ -1555,8 +1555,6 @@ static int kpatch_include_hook_elements(struct 
> kpatch_elf *kelf)
>                                 sym->sec->sym = NULL;
>                                 /* use section symbol instead */
>                                 rela->sym = sym->sec->secsym;
> -                       } else {
> -                               sec->secsym->include = 1;
>                         }
>                 }
>         }
> --
> 2.46.0
>

Reviewed-by: Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>

Thanks