[Xen-devel] [livepatch-build-tools part3 1/3] create-diff-object: Do not create empty .livepatch.funcs section

[Pawel Wieczorkiewicz <wipawel@xxxxxxxxx>]

When there is no changed function in the generated payload, do not
create an empty .livepatch.funcs section. Hypervisor code considers
such payloads as broken and rejects to load them.

Such payloads without any changed functions may appear when only
hooks are specified.

Signed-off-by: Pawel Wieczorkiewicz <wipawel@xxxxxxxxx>
Reviewed-by: Martin Mazein <amazein@xxxxxxxxx>
Reviewed-by: Martin Pohlack <mpohlack@xxxxxxxxx>

CR: https://code.amazon.com/reviews/CR-7368634
---
 create-diff-object.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/create-diff-object.c b/create-diff-object.c
index 82f777e..af2245c 100644
--- a/create-diff-object.c
+++ b/create-diff-object.c
@@ -1744,6 +1744,11 @@ static void livepatch_create_patches_sections(struct 
kpatch_elf *kelf,
                if (sym->type == STT_FUNC && sym->status == CHANGED)
                        nr++;
 
+       if (nr == 0) {
+               log_debug("No changed functions found. Skipping 
.livepatch.funcs section creation\n");
+               return;
+       }
+
        /* create text/rela section pair */
        sec = create_section_pair(kelf, ".livepatch.funcs", sizeof(*funcs), nr);
        relasec = sec->rela;
-- 
2.16.5




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