[PATCH v2] perf: Fix up build failure due to bpf changes

[PATCH v2] perf: Fix up build failure due to bpf changes

[Mark Brown]

Fix

util/btf.c: In function '__btf_type__find_member_by_name':
util/btf.c:19:43: error: comparison of integer expressions of different signedness: 'int' and '__u32' {aka 'unsigned int'} [-Werror=sign-compare]
   19 |         for (i = 0, m = btf_members(t); i < btf_vlen(t); i++, m++) {
      |                                           ^

builtin-trace.c: In function 'syscall_arg__strtoul_btf_enum':
builtin-trace.c:967:27: error: comparison of integer expressions of different signedness: 'int' and '__u32' {aka 'unsigned int'} [-Werror=sign-compare]
  967 |         for (int i = 0; i < btf_vlen(bt); ++i, ++be) {
      |                           ^

by making the variable the same type as the function.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
v2: Fix a second error.

 tools/perf/builtin-trace.c | 2 +-
 tools/perf/util/btf.c      | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 48615ddccd93a..4b23b82732e74 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -964,7 +964,7 @@ static bool syscall_arg__strtoul_btf_enum(char *bf, size_t size, struct syscall_
 	struct btf *btf = arg->trace->btf;
 	struct btf_enum *be = btf_enum(bt);
 
-	for (int i = 0; i < btf_vlen(bt); ++i, ++be) {
+	for (u32 i = 0; i < btf_vlen(bt); ++i, ++be) {
 		const char *name = btf__name_by_offset(btf, be->name_off);
 		int max_len = max(size, strlen(name));
 
diff --git a/tools/perf/util/btf.c b/tools/perf/util/btf.c
index bb163fe87767c..50d98f3e83bf0 100644
--- a/tools/perf/util/btf.c
+++ b/tools/perf/util/btf.c
@@ -14,7 +14,7 @@ const struct btf_member *__btf_type__find_member_by_name(struct btf *btf,
 {
 	const struct btf_type *t = btf__type_by_id(btf, type_id);
 	const struct btf_member *m;
-	int i;
+	u32 i;
 
 	for (i = 0, m = btf_members(t); i < btf_vlen(t); i++, m++) {
 		const char *current_member_name = btf__name_by_offset(btf, m->name_off);
-- 
2.47.3

Re: [PATCH v2] perf: Fix up build failure due to bpf changes

[Arnaldo Carvalho de Melo]

On Wed, Jun 17, 2026 at 02:00:38PM +0100, Mark Brown wrote:
> Fix
> 
> util/btf.c: In function '__btf_type__find_member_by_name':
> util/btf.c:19:43: error: comparison of integer expressions of different signedness: 'int' and '__u32' {aka 'unsigned int'} [-Werror=sign-compare]
>    19 |         for (i = 0, m = btf_members(t); i < btf_vlen(t); i++, m++) {
>       |                                           ^
> 
> builtin-trace.c: In function 'syscall_arg__strtoul_btf_enum':
> builtin-trace.c:967:27: error: comparison of integer expressions of different signedness: 'int' and '__u32' {aka 'unsigned int'} [-Werror=sign-compare]
>   967 |         for (int i = 0; i < btf_vlen(bt); ++i, ++be) {
>       |                           ^
> 
> by making the variable the same type as the function.

Thanks, applied to perf-tools-next, for v7.2.

- Arnaldo
 
> Signed-off-by: Mark Brown <broonie@kernel.org>
> ---
> v2: Fix a second error.
> 
>  tools/perf/builtin-trace.c | 2 +-
>  tools/perf/util/btf.c      | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
> index 48615ddccd93a..4b23b82732e74 100644
> --- a/tools/perf/builtin-trace.c
> +++ b/tools/perf/builtin-trace.c
> @@ -964,7 +964,7 @@ static bool syscall_arg__strtoul_btf_enum(char *bf, size_t size, struct syscall_
>  	struct btf *btf = arg->trace->btf;
>  	struct btf_enum *be = btf_enum(bt);
>  
> -	for (int i = 0; i < btf_vlen(bt); ++i, ++be) {
> +	for (u32 i = 0; i < btf_vlen(bt); ++i, ++be) {
>  		const char *name = btf__name_by_offset(btf, be->name_off);
>  		int max_len = max(size, strlen(name));
>  
> diff --git a/tools/perf/util/btf.c b/tools/perf/util/btf.c
> index bb163fe87767c..50d98f3e83bf0 100644
> --- a/tools/perf/util/btf.c
> +++ b/tools/perf/util/btf.c
> @@ -14,7 +14,7 @@ const struct btf_member *__btf_type__find_member_by_name(struct btf *btf,
>  {
>  	const struct btf_type *t = btf__type_by_id(btf, type_id);
>  	const struct btf_member *m;
> -	int i;
> +	u32 i;
>  
>  	for (i = 0, m = btf_members(t); i < btf_vlen(t); i++, m++) {
>  		const char *current_member_name = btf__name_by_offset(btf, m->name_off);
> -- 
> 2.47.3
> 
>