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

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

[Naresh Kamboju]

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@linaro.org>

## 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
                    ^~~

## 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

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@linaro.org> 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@linaro.org>
>
> ## 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

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

[Heiko Carstens]

On Mon, Jun 16, 2025 at 07:06:10PM +0530, Naresh Kamboju wrote:
> On Mon, 16 Jun 2025 at 17:36, Naresh Kamboju <naresh.kamboju@linaro.org> 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@linaro.org>
> >
> > ## 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()

I'll take a look at this tomorrow. I guess the easiest "fix" is to
change the s390 bug code similar to arm64, so that those problems with
inline asm constraints cannot happen anymore.

At least I hope that will work. We'll see.