[PATCH] x86/cfi: add __init_or_module annotations for fineibt

From: Calvin Owens

Date: Mon May 25 2026 - 23:23:23 EST


I'm seeing some benign section mismatch warnings with fineibt when
building kernels with CONFIG_MODULES=n:

WARNING: modpost: vmlinux: section mismatch in reference: __apply_fineibt+0x1db (section: .text) -> text_poke_early (section: .init.text)
WARNING: modpost: vmlinux: section mismatch in reference: __apply_fineibt+0x473 (section: .text) -> text_poke_early (section: .init.text)
WARNING: modpost: vmlinux: section mismatch in reference: __apply_fineibt+0x57c (section: .text) -> text_poke_early (section: .init.text)
WARNING: modpost: vmlinux: section mismatch in reference: __apply_fineibt+0x6d9 (section: .text) -> text_poke_early (section: .init.text)
WARNING: modpost: vmlinux: section mismatch in reference: __apply_fineibt+0xb57 (section: .text) -> text_poke_early (section: .init.text)
WARNING: modpost: vmlinux: section mismatch in reference: __apply_fineibt+0xb81 (section: .text) -> text_poke_early (section: .init.text)
WARNING: modpost: vmlinux: section mismatch in reference: __apply_fineibt+0xd00 (section: .text) -> poison_endbr (section: .init.text)
WARNING: modpost: vmlinux: section mismatch in reference: __apply_fineibt+0xdd3 (section: .text) -> text_poke_early (section: .init.text)
WARNING: modpost: vmlinux: section mismatch in reference: __apply_fineibt+0xe58 (section: .text) -> text_poke_early (section: .init.text)
WARNING: modpost: vmlinux: section mismatch in reference: __apply_fineibt+0xe85 (section: .text) -> text_poke_early (section: .init.text)
WARNING: modpost: vmlinux: section mismatch in reference: apply_fineibt+0x8 (section: .text.unlikely.) -> __apply_fineibt (section: .init.text)

Add the missing __init_or_module section annotations to fix the
warnings, and also free up a tiny bit of memory after boot.

Signed-off-by: Calvin Owens <calvin@xxxxxxxxxx>
---
arch/x86/kernel/alternative.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 62936a3bde19..400baffcd609 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -1775,8 +1775,8 @@ static int cfi_rewrite_callers(s32 *start, s32 *end)
#define FINEIBT_WARN(_f, _v) \
WARN_ONCE((_f) != (_v), "FineIBT: " #_f " %ld != %d\n", _f, _v)

-static void __apply_fineibt(s32 *start_retpoline, s32 *end_retpoline,
- s32 *start_cfi, s32 *end_cfi, bool builtin)
+static void __init_or_module __apply_fineibt(s32 *start_retpoline, s32 *end_retpoline,
+ s32 *start_cfi, s32 *end_cfi, bool builtin)
{
int ret;

@@ -2088,8 +2088,8 @@ bool decode_fineibt_insn(struct pt_regs *regs, unsigned long *target, u32 *type)

#else /* !CONFIG_FINEIBT: */

-static void __apply_fineibt(s32 *start_retpoline, s32 *end_retpoline,
- s32 *start_cfi, s32 *end_cfi, bool builtin)
+static void __init_or_module __apply_fineibt(s32 *start_retpoline, s32 *end_retpoline,
+ s32 *start_cfi, s32 *end_cfi, bool builtin)
{
if (IS_ENABLED(CONFIG_CFI) && builtin)
pr_info("CFI: Using standard kCFI\n");
@@ -2101,8 +2101,8 @@ static void poison_cfi(void *addr) { }

#endif /* !CONFIG_FINEIBT */

-void apply_fineibt(s32 *start_retpoline, s32 *end_retpoline,
- s32 *start_cfi, s32 *end_cfi)
+void __init_or_module apply_fineibt(s32 *start_retpoline, s32 *end_retpoline,
+ s32 *start_cfi, s32 *end_cfi)
{
return __apply_fineibt(start_retpoline, end_retpoline,
start_cfi, end_cfi,
--
2.47.3