Re: next-20250616: S390 gcc-8 allnoconfig mm mempool.c In function remove_element

[Naresh Kamboju]

On Mon, 16 Jun 2025 at 17:36, Naresh Kamboju <naresh.kamboju@xxxxxxxxxx> wrote:
>
> Regression while building S390 with the Linux next-20250616
> with gcc-8 the following kernel warnings found.
>
> Regressions found on S390
>  -  build/gcc-8-lkftconfig-allnoconfig
>  -  build/gcc-8-lkftconfig-hardening
>
> Regression Analysis:
>  - New regression? Yes
>  - Reproducibility? Yes
>
> First seen on the next-20250616
> Good: next-20250613
> Bad:  next-20250616
>
> Build regression: S390 gcc-8 allnoconfig mm mempool.c In function remove_element
>
> Reported-by: Linux Kernel Functional Testing <lkft@xxxxxxxxxx>
>
> ## Build errors
> mm/mempool.c: In function 'remove_element':
> include/linux/compiler_types.h:497:20: warning: asm operand 0 probably
> doesn't match constraints
>  #define asm_inline asm __inline
>                     ^~~
> arch/s390/include/asm/bug.h:12:2: note: in expansion of macro 'asm_inline'
>   asm_inline volatile(     \
>   ^~~~~~~~~~
> arch/s390/include/asm/bug.h:43:2: note: in expansion of macro '__EMIT_BUG'
>   __EMIT_BUG("", 0);    \
>   ^~~~~~~~~~
> include/asm-generic/bug.h:77:57: note: in expansion of macro 'BUG'
>  #define BUG_ON(condition) do { if (unlikely(condition)) BUG(); } while (0)
>                                                          ^~~
> mm/mempool.c:149:2: note: in expansion of macro 'BUG_ON'
>   BUG_ON(pool->curr_nr < 0);
>   ^~~~~~
> include/linux/compiler_types.h:497:20: error: impossible constraint in 'asm'
>  #define asm_inline asm __inline
>                     ^~~

Anders bisect this build regressions and found,

 # first bad commit:
    [45c79ca947c936085c94b716be92eaf9a1bdc8bb]
    bugs/s390: Use 'cond_str' in __EMIT_BUG()


> ## Source
> * Kernel version: 6.16.0-rc2
> * Git tree: https://kernel.googlesource.com/pub/scm/linux/kernel/git/next/linux-next.git
> * Git sha: 050f8ad7b58d9079455af171ac279c4b9b828c11
> * Git describe: next-20250616
> * Project details:
> https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20250616/
> * Architectures: S390
> * Toolchains: gcc-8
> * Kconfigs: allnoconfig
>
> ## Build S390
> * Build log: https://qa-reports.linaro.org/api/testruns/28763376/log_file/
> * Build details:
> https://regressions.linaro.org/lkft/linux-next-master/next-20250616/build/gcc-8-allnoconfig/
> * Build link: https://storage.tuxsuite.com/public/linaro/lkft/builds/2ya0wQbvgatYAbcvC2OTZls5D91/
> * Kernel config:
> https://storage.tuxsuite.com/public/linaro/lkft/builds/2ya0wQbvgatYAbcvC2OTZls5D91/config
>
> ## Steps to reproduce on S390
>  - tuxmake --runtime podman --target-arch s390 --toolchain gcc-8
> --kconfig allnoconfig
>
> --
> Linaro LKFT
> https://lkft.linaro.org

- Naresh