Re: [PATCH perf-tools-next v4 2/5] perf ftrace: Support filtering return address comments

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] perf: build failure due to unused variable 'endptr'
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commit 8db97766d362752b2eec14b113b39acd9e702f2a
Author: Aaron Tomlin <atomlin@atomlin.com>

perf ftrace: Support filtering return address comments

This commit introduces support for filtering out return address comments from
function graph trace output in perf ftrace. It adds the --filter-retaddr flag
and implements the parsing and filtering logic.

> diff --git a/tools/perf/util/ftrace.c b/tools/perf/util/ftrace.c
> new file mode 100644
> index 0000000000000..344d36293f5ca
> --- /dev/null
> +++ b/tools/perf/util/ftrace.c
[ ... ]
> +bool ftrace_parse_retaddr(const char *str, char *sym_name, size_t sym_len, u64 *offset)
> +{
> +	const char *p = strstr(str, "<-");
> +	const char *plus;
> +	const char *bracket;
> +	char *endptr;
> +	size_t name_len;
[ ... ]
> +	memcpy(sym_name, p, name_len);
> +	sym_name[name_len] = '\0';
> +
> +	*offset = strtoull(plus + 1, &endptr, 16);

[Severity: Low]
Will this cause a build failure due to an unused variable?

The tools/perf build system enables -Werror by default, which elevates
-Wunused-but-set-variable to a build failure. The local variable endptr
is written to by strtoull() but is never subsequently read or evaluated.

Could we pass NULL to strtoull() instead to resolve this and avoid breaking
the build?

> +	return true;
> +}

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Sashiko AI review · https://sashiko.dev/#/patchset/20261014161457.373253-1-atomlin@atomlin.com?part=2