* [PATCH v1] perf loongarch: Fix discarded const qualifier in _get_field()
@ 2026-09-24 2:17 Tiezhu Yang
2026-09-24 2:24 ` sashiko-bot
2026-09-24 5:23 ` Namhyung Kim
0 siblings, 2 replies; 4+ messages in thread
From: Tiezhu Yang @ 2026-09-24 2:17 UTC (permalink / raw)
To: Huacai Chen, Arnaldo Carvalho de Melo, Namhyung Kim
Cc: loongarch, linux-perf-users, linux-kernel
When building perf on LoongArch, the following compilation errors occur:
CC arch/loongarch/util/header.o
arch/loongarch/util/header.c: In function '_get_field':
arch/loongarch/util/header.c:31:15: error: assignment discards 'const' qualifier from pointer target type [-Werror=discarded-qualifiers]
31 | line2 = strrchr(line, ' ');
| ^
arch/loongarch/util/header.c:36:12: error: assignment discards 'const' qualifier from pointer target type [-Werror=discarded-qualifiers]
36 | nl = strrchr(line, '\n');
| ^
cc1: all warnings being treated as errors
Declare 'line2' and 'nl' as const char * to ensure type safety. In modern
glibc versions, strrchr() returns a 'const char *' if the input string is
const.
This is similar to commit 7378b6656aa4 ("perf riscv: Fix discarded const
qualifier in _get_field()").
Fixes: 492ac37fa38f ("perf kvm: Add kvm-stat for loongarch64")
Cc: stable@vger.kernel.org
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
---
| 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--git a/tools/perf/arch/loongarch/util/header.c b/tools/perf/arch/loongarch/util/header.c
index 0c6d823334a2..46f53a74f71e 100644
--- a/tools/perf/arch/loongarch/util/header.c
+++ b/tools/perf/arch/loongarch/util/header.c
@@ -26,7 +26,7 @@
static char *_get_field(const char *line)
{
- char *line2, *nl;
+ const char *line2, *nl;
line2 = strrchr(line, ' ');
if (!line2)
--
2.42.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH v1] perf loongarch: Fix discarded const qualifier in _get_field()
2026-09-24 2:17 [PATCH v1] perf loongarch: Fix discarded const qualifier in _get_field() Tiezhu Yang
@ 2026-09-24 2:24 ` sashiko-bot
2026-09-24 5:23 ` Namhyung Kim
1 sibling, 0 replies; 4+ messages in thread
From: sashiko-bot @ 2026-09-24 2:24 UTC (permalink / raw)
To: Tiezhu Yang; +Cc: linux-perf-users
> When building perf on LoongArch, the following compilation errors occur:
>
> CC arch/loongarch/util/header.o
> arch/loongarch/util/header.c: In function '_get_field':
> arch/loongarch/util/header.c:31:15: error: assignment discards 'const' qualifier from pointer target type [-Werror=discarded-qualifiers]
> 31 | line2 = strrchr(line, ' ');
> | ^
> arch/loongarch/util/header.c:36:12: error: assignment discards 'const' qualifier from pointer target type [-Werror=discarded-qualifiers]
> 36 | nl = strrchr(line, '\n');
> | ^
> cc1: all warnings being treated as errors
>
> Declare 'line2' and 'nl' as const char * to ensure type safety. In modern
> glibc versions, strrchr() returns a 'const char *' if the input string is
> const.
>
> This is similar to commit 7378b6656aa4 ("perf riscv: Fix discarded const
> qualifier in _get_field()").
>
> Fixes: 492ac37fa38f ("perf kvm: Add kvm-stat for loongarch64")
> Cc: stable@vger.kernel.org
> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Sashiko has reviewed this patch and found no issues. It looks great!
--
Sashiko AI review · https://sashiko.dev/#/patchset/20260924021756.22433-1-yangtiezhu@loongson.cn?part=1
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH v1] perf loongarch: Fix discarded const qualifier in _get_field()
2026-09-24 2:17 [PATCH v1] perf loongarch: Fix discarded const qualifier in _get_field() Tiezhu Yang
2026-09-24 2:24 ` sashiko-bot
@ 2026-09-24 5:23 ` Namhyung Kim
2026-09-24 17:22 ` Arnaldo Carvalho de Melo
1 sibling, 1 reply; 4+ messages in thread
From: Namhyung Kim @ 2026-09-24 5:23 UTC (permalink / raw)
To: Tiezhu Yang
Cc: Huacai Chen, Arnaldo Carvalho de Melo, loongarch,
linux-perf-users, linux-kernel
On Thu, Sep 24, 2026 at 10:17:56AM +0800, Tiezhu Yang wrote:
> When building perf on LoongArch, the following compilation errors occur:
>
> CC arch/loongarch/util/header.o
> arch/loongarch/util/header.c: In function '_get_field':
> arch/loongarch/util/header.c:31:15: error: assignment discards 'const' qualifier from pointer target type [-Werror=discarded-qualifiers]
> 31 | line2 = strrchr(line, ' ');
> | ^
> arch/loongarch/util/header.c:36:12: error: assignment discards 'const' qualifier from pointer target type [-Werror=discarded-qualifiers]
> 36 | nl = strrchr(line, '\n');
> | ^
> cc1: all warnings being treated as errors
>
> Declare 'line2' and 'nl' as const char * to ensure type safety. In modern
> glibc versions, strrchr() returns a 'const char *' if the input string is
> const.
>
> This is similar to commit 7378b6656aa4 ("perf riscv: Fix discarded const
> qualifier in _get_field()").
>
> Fixes: 492ac37fa38f ("perf kvm: Add kvm-stat for loongarch64")
> Cc: stable@vger.kernel.org
> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Thanks,
Namhyung
> ---
> tools/perf/arch/loongarch/util/header.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/perf/arch/loongarch/util/header.c b/tools/perf/arch/loongarch/util/header.c
> index 0c6d823334a2..46f53a74f71e 100644
> --- a/tools/perf/arch/loongarch/util/header.c
> +++ b/tools/perf/arch/loongarch/util/header.c
> @@ -26,7 +26,7 @@
>
> static char *_get_field(const char *line)
> {
> - char *line2, *nl;
> + const char *line2, *nl;
>
> line2 = strrchr(line, ' ');
> if (!line2)
> --
> 2.42.0
>
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH v1] perf loongarch: Fix discarded const qualifier in _get_field()
2026-09-24 5:23 ` Namhyung Kim
@ 2026-09-24 17:22 ` Arnaldo Carvalho de Melo
0 siblings, 0 replies; 4+ messages in thread
From: Arnaldo Carvalho de Melo @ 2026-09-24 17:22 UTC (permalink / raw)
To: Namhyung Kim
Cc: Tiezhu Yang, Huacai Chen, loongarch, linux-perf-users,
linux-kernel
On Wed, Sep 23, 2026 at 10:23:27PM -0700, Namhyung Kim wrote:
> On Thu, Sep 24, 2026 at 10:17:56AM +0800, Tiezhu Yang wrote:
> > When building perf on LoongArch, the following compilation errors occur:
> >
> > CC arch/loongarch/util/header.o
> > arch/loongarch/util/header.c: In function '_get_field':
> > arch/loongarch/util/header.c:31:15: error: assignment discards 'const' qualifier from pointer target type [-Werror=discarded-qualifiers]
> > 31 | line2 = strrchr(line, ' ');
> > | ^
> > arch/loongarch/util/header.c:36:12: error: assignment discards 'const' qualifier from pointer target type [-Werror=discarded-qualifiers]
> > 36 | nl = strrchr(line, '\n');
> > | ^
> > cc1: all warnings being treated as errors
> >
> > Declare 'line2' and 'nl' as const char * to ensure type safety. In modern
> > glibc versions, strrchr() returns a 'const char *' if the input string is
> > const.
> >
> > This is similar to commit 7378b6656aa4 ("perf riscv: Fix discarded const
> > qualifier in _get_field()").
> >
> > Fixes: 492ac37fa38f ("perf kvm: Add kvm-stat for loongarch64")
> > Cc: stable@vger.kernel.org
> > Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
>
> Acked-by: Namhyung Kim <namhyung@kernel.org>
Thanks, applied to perf-tools-next, for v7.4.
- Arnaldo
^ permalink raw reply [flat|nested] 4+ messages in thread
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2026-09-24 2:17 [PATCH v1] perf loongarch: Fix discarded const qualifier in _get_field() Tiezhu Yang
2026-09-24 2:24 ` sashiko-bot
2026-09-24 5:23 ` Namhyung Kim
2026-09-24 17:22 ` Arnaldo Carvalho de Melo
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