Re: next-20250912: riscv: s390: mm/kasan/shadow.c 'kasan_populate_vmalloc_pte' pgtable.h:247:41: error: statement with no effect [-Werror=unused-value]

[David Hildenbrand <david@redhat.com>]

On 12.09.25 13:32, Naresh Kamboju wrote:
> The following build warnings / errors noticed on the riscv and s390
> with allyesconfig build on the Linux next-20250912 tag.
> 
> Regression Analysis:
> - New regression? yes
> - Reproducibility? yes
> 
> Build regression: next-20250912 mm/kasan/shadow.c
> 'kasan_populate_vmalloc_pte' pgtable.h error statement with no effect
> [-Werror=unused-value]
> 
> Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
> 
> $ git log --oneline next-20250911..next-20250912 --  mm/kasan/shadow.c
>    aed53ec0b797a mm: introduce local state for lazy_mmu sections
>    307f2dc9b308e kasan: introduce ARCH_DEFER_KASAN and unify static key
> across modes
> 
> ## Test log
> In file included from include/linux/kasan.h:37,
>                   from mm/kasan/shadow.c:14:
> mm/kasan/shadow.c: In function 'kasan_populate_vmalloc_pte':
> include/linux/pgtable.h:247:41: error: statement with no effect
> [-Werror=unused-value]
>    247 | #define arch_enter_lazy_mmu_mode()      (LAZY_MMU_DEFAULT)
>        |                                         ^
> mm/kasan/shadow.c:322:9: note: in expansion of macro 'arch_enter_lazy_mmu_mode'
>    322 |         arch_enter_lazy_mmu_mode();
>        |         ^~~~~~~~~~~~~~~~~~~~~~~~
> mm/kasan/shadow.c: In function 'kasan_depopulate_vmalloc_pte':
> include/linux/pgtable.h:247:41: error: statement with no effect
> [-Werror=unused-value]
>    247 | #define arch_enter_lazy_mmu_mode()      (LAZY_MMU_DEFAULT)
>        |                                         ^
> mm/kasan/shadow.c:497:9: note: in expansion of macro 'arch_enter_lazy_mmu_mode'
>    497 |         arch_enter_lazy_mmu_mode();
>        |         ^~~~~~~~~~~~~~~~~~~~~~~~
> cc1: all warnings being treated as errors
> 


I'm afraid these changes landed in -mm-unstable a bit too early.


-- 
Cheers

David / dhildenb