elf_validity...he_index_mod(9)

💅 elf_validity_cache_index_mod(9) 💅

okay so bestie, this page is from the Kernel API Manual ✨ and it's giving “tiny validator with main character energy” — but make no mistake, every check here matters. Let's get into it 🫶

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🌸 NAME 🌸

elf_validity_cache_index_mod — Validates and caches this_module section 💖

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✨ SYNOPSIS ✨

int elf_validity_cache_index_mod (struct load_info *info );

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🎀 ARGUMENTS 🎀

• info — Load info to cache this_module on. Must have load_info->sechdrs and load_info->secstrings populated. No cap, those fields gotta be there 🫡

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🦋 DESCRIPTION 🦋

The .gnu.linkonce.this_module ELF section is special, okay? It's what modpost uses to refer to __this_module, and it's how we rely on THIS_MODULE pointing to __this_module properly. The kernel's modpost declares it on each module's *.mod.c file. And if the struct module of the kernel changes, a full kernel rebuild is required — like, literally, not optional 💀

We have a few expectations for this special section, and this function validates all of them for us:

• The section has contents ✅
• The section is unique ✅
• We expect the kernel to always have to allocate it: SHF_ALLOC ✅
• The section size must match the kernel's run time's struct module size ✅

If all checks pass, the index will be cached in load_info->index.mod — slay, cached and validated 💅

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🔥 RETURN 🔥

0 on validation success, -ENOEXEC on failure. That's the whole vibe check 😤

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👑 SEE ALSO 👑

Kernel file ./kernel/module/main.c and these besties:

• find_any_unique_sec(9)
• is_module_percpu_address(9)
• module_refcount(9)
• verify_module_namespace(9)
• elf_validity_ehdr(9)
• elf_validity_cache_sechdrs(9)
• elf_validity_cache_secstrings(9)
• elf_validity_cache_index_info(9)
• elf_validity_cache_index_sym(9)
• elf_validity_cache_index_str(9)
• elf_validity_cache_index_versions(9)
• elf_validity_cache_index(9)
• elf_validity_cache_strtab(9)
• is_module_address(9)
• __module_address(9)
• is_module_text_address(9)
• __module_text_address(9)

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xoxo, your kernel bestie 💅 — source/version: ./kernel/module, dated October 2026 🎀