i386: kernel/sched/debug.c:341:57: error: integer overflow in expression of type 'long int' results in '-100663296' [-Werror=overflow]

i386: kernel/sched/debug.c:341:57: error: integer overflow in expression of type 'long int' results in '-100663296' [-Werror=overflow]

[Naresh Kamboju]

The i386 kselftest merge config build failed due to following warnings / errors
on today's Linux next-20240801 tag with gcc-13.

Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>

Build log:
--------
In file included from kernel/sched/build_utility.c:72:
kernel/sched/debug.c:341:57: error: integer overflow in expression of
type 'long int' results in '-100663296' [-Werror=overflow]
  341 | static unsigned long fair_server_period_max = (1 << 22) *
NSEC_PER_USEC; /* ~4 seconds */
      |                                                         ^
cc1: all warnings being treated as errors

Steps to reproduce:
---
 - https://storage.tuxsuite.com/public/linaro/lkft/builds/2k2tW5pcf7uulmRCWIAWeormjb0/tuxmake_reproducer.sh

metadata:
------
  git_describe: next-20240801
  git_repo: https://gitlab.com/Linaro/lkft/mirrors/next/linux-next
  git_sha: 048d8cb65cde9fe7534eb4440bcfddcf406bb49c
  git_short_log: 048d8cb65cde ("Add linux-next specific files for 20240801")
  compiler: {'name': 'i686-linux-gnu-gcc', 'version': '13',
'version_full': 'i686-linux-gnu-gcc (Debian 13.2.0-12) 13.2.0'}
  arch: i386
  build_name: gcc-13-lkftconfig-kselftest
  config: https://storage.tuxsuite.com/public/linaro/lkft/builds/2k2tW5pcf7uulmRCWIAWeormjb0/config
  download_url:
https://storage.tuxsuite.com/public/linaro/lkft/builds/2k2tW5pcf7uulmRCWIAWeormjb0/

--
Linaro LKFT
https://lkft.linaro.org

Re: i386: kernel/sched/debug.c:341:57: error: integer overflow in expression of type 'long int' results in '-100663296' [-Werror=overflow]

[Dan Carpenter]

On Thu, Aug 01, 2024 at 08:42:07PM +0530, Naresh Kamboju wrote:
> The i386 kselftest merge config build failed due to following warnings / errors
> on today's Linux next-20240801 tag with gcc-13.
> 
> Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
> 
> Build log:
> --------
> In file included from kernel/sched/build_utility.c:72:
> kernel/sched/debug.c:341:57: error: integer overflow in expression of
> type 'long int' results in '-100663296' [-Werror=overflow]
>   341 | static unsigned long fair_server_period_max = (1 << 22) *
> NSEC_PER_USEC; /* ~4 seconds */
>       |                                                         ^
> cc1: all warnings being treated as errors

It needs to be 1U << 22.  It's probably more traditional to write it as
1UL << 22, although they equivalent here.

I can send a patch for that.

regards,
dan carpenter