regression in 6.6.91: arch/x86/kernel/alternative.c:1452:5: error: redefinition of 'its_static_thunk'

Hi!

When building 6.6.91 for Alpine Linux I got this error on 32 bit x86:

CC net/devlink/dpipe.o
/home/buildozer/aports/main/linux-lts/src/linux-6.6/arch/x86/kernel/alternative.c:1452:5: error: redefinition of 'its_static_thunk'
1452 | u8 *its_static_thunk(int reg)

      |     ^~~~~~~~~~~~~~~~

In file included from /home/buildozer/aports/main/linux-lts/src/linux-6.6/arch/x86/include/asm/barrier.h:5,
from /home/buildozer/aports/main/linux-lts/src/linux-6.6/include/linux/list.h:11,
from /home/buildozer/aports/main/linux-lts/src/linux-6.6/include/linux/module.h:12,
from /home/buildozer/aports/main/linux-lts/src/linux-6.6/arch/x86/kernel/alternative.c:4:
/home/buildozer/aports/main/linux-lts/src/linux-6.6/arch/x86/include/asm/alternative.h:143:19: note: previous definition of 'its_static_thunk' with type 'u8 *(int)' {aka 'unsigned char *(int)'}
143 | static inline u8 *its_static_thunk(int reg)

      |                   ^~~~~~~~~~~~~~~~

CC [M] net/sched/act_skbmod.o
make[4]: *** [/home/buildozer/aports/main/linux-lts/src/linux-6.6/scripts/Makefile.build:243: arch/x86/kernel/alternative.o] Error 1 make[3]: *** [/home/buildozer/aports/main/linux-lts/src/linux-6.6/scripts/Makefile.build:480: arch/x86/kernel] Error 2 make[3]: *** Waiting for unfinished jobs....

I believe this was introduce with

commit 772934d9062a0f7297ad4e5bffbd904208655660

Author: Peter Zijlstra <[email protected]>
Date:   Wed Apr 23 09:57:31 2025 +0200

x86/its: FineIBT-paranoid vs ITS

commit e52c1dc7455d32c8a55f9949d300e5e87d011fa6 upstream.

Thanks, I've cc:ed you on the thread that caused this issue.

greg k-h