From 3112397f3b7b59f8e9089143965d889165c16d13 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Mon, 6 Jun 2022 17:05:41 -0700 Subject: [PATCH] create-diff-object: Create missing section symbol Recent toolchains only create a section symbol if it's needed, i.e. if there's a reference to it. If there's a missing section symbol in kpatch_create_intermediate_sections(), create one instead of erroring out. Fixes #1272. Signed-off-by: Josh Poimboeuf --- kpatch-build/create-diff-object.c | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-) diff --git a/kpatch-build/create-diff-object.c b/kpatch-build/create-diff-object.c index 319ed68d..420d55d8 100644 --- a/kpatch-build/create-diff-object.c +++ b/kpatch-build/create-diff-object.c @@ -3397,12 +3397,23 @@ static void kpatch_create_intermediate_sections(struct kpatch_elf *kelf, /* add rela to fill in krelas[index].dest field */ ALLOC_LINK(rela2, &krela_sec->rela->relas); - if (sec->base->secsym) - rela2->sym = sec->base->secsym; - else - ERROR("can't create dynrela for section %s (symbol %s): no bundled or section symbol", - sec->name, rela->sym->name); + if (!sec->base->secsym) { + struct symbol *sym; + /* + * Newer toolchains are stingy with their + * section symbols, create one if it doesn't + * exist already. + */ + ALLOC_LINK(sym, &kelf->symbols); + sym->sec = sec->base; + sym->sym.st_info = GELF_ST_INFO(STB_LOCAL, STT_SECTION); + sym->type = STT_SECTION; + sym->bind = STB_LOCAL; + sym->name = sec->base->name; + sec->base->secsym = sym; + } + rela2->sym = sec->base->secsym; rela2->type = absolute_rela_type(kelf); rela2->addend = rela->offset; rela2->offset = (unsigned int)(index * sizeof(*krelas) + \