Re: [PATCH] perf dwarf-regs: s390: Fix an off by one bug

[Ian Rogers]

On Thu, Apr 23, 2026 at 12:07 AM Dan Carpenter <error27@xxxxxxxxx> wrote:
>
> Change the > comparison to >= to prevent an out of bounds access of
> the dwarf_s390_regnums[] array.
>
> Fixes: 1e452dd850f3 ("perf dwarf-regs: Add S390 perf to DWARF register number mapping functions")
> Signed-off-by: Dan Carpenter <error27@xxxxxxxxx>
> ---
>  tools/perf/util/dwarf-regs-arch/dwarf-regs-s390.c | 1 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/tools/perf/util/dwarf-regs-arch/dwarf-regs-s390.c b/tools/perf/util/dwarf-regs-arch/dwarf-regs-s390.c
> index 310a37451bdc..f79216a7665a 100644
> --- a/tools/perf/util/dwarf-regs-arch/dwarf-regs-s390.c
> +++ b/tools/perf/util/dwarf-regs-arch/dwarf-regs-s390.c
> @@ -45,7 +45,7 @@ int __get_dwarf_regnum_for_perf_regnum_s390(int perf_regnum)
>         if (perf_regnum == 0)
>                 return 0;
>
> -       if (perf_regnum <  0 || perf_regnum > (int)ARRAY_SIZE(dwarf_s390_regnums) ||
> +       if (perf_regnum <  0 || perf_regnum >= (int)ARRAY_SIZE(dwarf_s390_regnums) ||

It looks like this mistake was copy-pasted into these files as well:
 - tools/perf/util/dwarf-regs-arch/dwarf-regs-csky.c
 - tools/perf/util/dwarf-regs-arch/dwarf-regs-x86.c
 - tools/perf/util/dwarf-regs-arch/dwarf-regs-powerpc.c

Could you fix them all?

Thanks,
Ian

>             dwarf_s390_regnums[perf_regnum] == 0)
>                 return -ENOENT;
>
> --
> 2.53.0
>