Re: [PATCH stable 6.1 3/3] perf build: Disable fewer bison warnings

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] The updated `sed` regex for parsing the bison version strictly requires three numeric components, causing a shell syntax error for two-component versions.
--

commit e696603d6c95e1ec405be3442c49513276f5ee86
Author: Ian Rogers <irogers@google.com>

perf build: Disable fewer bison warnings

This commit reduces the number of disabled bison C warnings for bison versions
3.8.2 and later. It also avoids implicit declarations of yylex by adding
declarations directly in the C files.

Link: https://lore.kernel.org/r/20230728064917.767761-6-irogers@google.com

> diff --git a/tools/perf/util/Build b/tools/perf/util/Build
> index e315ecaec3233..b65ce3563bedd 100644
> --- a/tools/perf/util/Build
> +++ b/tools/perf/util/Build
> @@ -269,10 +269,14 @@ CFLAGS_parse-events-flex.o  += $(flex_flags)
>  CFLAGS_pmu-flex.o           += $(flex_flags)
>  CFLAGS_expr-flex.o          += $(flex_flags)
>  
> -bison_flags := -DYYENABLE_NLS=0
> -BISON_GE_35 := $(shell expr $(shell $(BISON) --version | grep bison | sed -e 's/.\+ \([0-9]\+\).\([0-9]\+\)/\1\2/g') \>\= 35)
> -ifeq ($(BISON_GE_35),1)
> -  bison_flags += -Wno-unused-parameter -Wno-nested-externs -Wno-implicit-function-declaration -Wno-switch-enum -Wno-unused-but-set-variable -Wno-unknown-warning-option
> +# Some newer clang and gcc version complain about this
> +# util/parse-events-bison.c:1317:9: error: variable 'parse_events_nerrs' set but not used [-Werror,-Wunused-but-set-variable]
> +#  int yynerrs = 0;
> +
> +bison_flags := -DYYENABLE_NLS=0 -Wno-unused-but-set-variable
> +BISON_GE_382 := $(shell expr $(shell $(BISON) --version | grep bison | sed -e 's/.\+ \([0-9]\+\).\([0-9]\+\).\([0-9]\+\)/\1\2\3/g') \>\= 382)

[Severity: Low]
Will this new regex cause shell syntax errors for two-component version
strings like "bison (GNU Bison) 3.8"?

If the sed pattern strictly requires three numeric components, it will
fail to match a two-component string and output the unmodified string
instead.

When make passes this raw string containing unescaped parentheses
to expr, it will cause the shell to abort with a syntax error like
'sh: Syntax error: "(" unexpected' and fail the version check.

> +ifeq ($(BISON_GE_382),1)
> +  bison_flags += -Wno-switch-enum
>  else
>    bison_flags += -w
>  endif

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260519185154.2987285-1-florian.fainelli@broadcom.com?part=3