Re: arch/riscv/kernel/alternative.c:198:6: error: use of undeclared identifier '__vdso_alternatives_start_offset'; did you mean '__vdso_alternatives_start_cfi_offset'?

[Thomas Weißschuh]

On Tue, Oct 13, 2026 at 05:01:07PM +0200, kernel test robot wrote:
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head:   24a19b953e2a3d0ea5a8c4951a0ab8f32720c907
> commit: 63aecaba41a4b2593697f208e91bf542248ec4f8 riscv: alternative: Use the statically extracted vDSO section offsets
> date:   10 weeks ago
> config: riscv-randconfig-r2104-20261013 (https://download.01.org/0day-ci/archive/20261013/202610131613.BpOi6VPp-lkp@xxxxxxxxx/config)
> compiler: clang version 24.0.0git (https://github.com/llvm/llvm-project ce2a4984a3f43327a2b7c40baa74907bc10eb899)
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20261013/202610131613.BpOi6VPp-lkp@xxxxxxxxx/reproduce)
> 
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Fixes: 63aecaba41a4 ("riscv: alternative: Use the statically extracted vDSO section offsets")
> | Reported-by: kernel test robot <lkp@xxxxxxxxx>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202610131613.BpOi6VPp-lkp@xxxxxxxxx/
> 
> All errors (new ones prefixed by >>):
> 
> >> arch/riscv/kernel/alternative.c:198:6: error: use of undeclared identifier '__vdso_alternatives_start_offset'; did you mean '__vdso_alternatives_start_cfi_offset'?
>      198 |                                         __vdso_alternatives_start_offset,
>          |                                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>          |                                         __vdso_alternatives_start_cfi_offset
>    arch/riscv/include/asm/vdso.h:29:15: note: '__vdso_alternatives_start_cfi_offset' declared here
>       29 | extern size_t __vdso_alternatives_start_cfi_offset, __vdso_alternatives_end_cfi_offset;
>          |               ^
> >> arch/riscv/kernel/alternative.c:199:6: error: use of undeclared identifier '__vdso_alternatives_end_offset'; did you mean '__vdso_alternatives_end_cfi_offset'?
>      199 |                                         __vdso_alternatives_end_offset);
>          |                                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>          |                                         __vdso_alternatives_end_cfi_offset
>    arch/riscv/include/asm/vdso.h:29:53: note: '__vdso_alternatives_end_cfi_offset' declared here
>       29 | extern size_t __vdso_alternatives_start_cfi_offset, __vdso_alternatives_end_cfi_offset;
>          |                                                     ^
>    2 errors generated.

This looks to be a only a follow-up error.
The real issue is https://lore.kernel.org/all/20261009214501.GA905361@ax162/.
Which leads to no vDSO being generated and an empty vdso-offsets.h.
In addition to fixing the linked issue, we should also make sure that the build
properly aborts if one of the intermediate steps fails.

> vim +198 arch/riscv/kernel/alternative.c
> 
>    186	
>    187	void __init apply_boot_alternatives(void)
>    188	{
>    189		/* If called on non-boot cpu things could go wrong */
>    190		WARN_ON(smp_processor_id() != 0);
>    191	
>    192		_apply_alternatives((struct alt_entry *)__alt_start,
>    193				    (struct alt_entry *)__alt_end,
>    194				    RISCV_ALTERNATIVES_BOOT);
>    195	
>    196		if (IS_ENABLED(CONFIG_MMU))
>    197			apply_vdso_alternatives(vdso_start,
>  > 198						__vdso_alternatives_start_offset,
>  > 199						__vdso_alternatives_end_offset);
>    200	
>    201		if (IS_ENABLED(CONFIG_RISCV_USER_CFI))
>    202			apply_vdso_alternatives(vdso_cfi_start,
>    203						__vdso_alternatives_start_cfi_offset,
>    204						__vdso_alternatives_end_cfi_offset);
>    205	}
>    206	
> 
> --
> 0-DAY CI Kernel Test Service
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