Re: [PATCH v1 3/8] perf tools: Check system path when check debuginfo

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] perf tools: Loss of DWARF support for .gnu_debugdata and .zdebug_info
--

commit 945ce7f07042383e50c7db270f3808ce02dd95b3
Author: Namhyung Kim <namhyung@kernel.org>

perf tools: Check system path when check debuginfo

This commit removes the fallback to open the given binary path in
debuginfo__new() and instead relies on checking the SYSTEM_PATH_DSO
type within dso__find_dbginfo_type().

> diff --git a/tools/perf/util/debuginfo.c b/tools/perf/util/debuginfo.c
> index d6bd0fcc22648..2669d5f5ee612 100644
> --- a/tools/perf/util/debuginfo.c
> +++ b/tools/perf/util/debuginfo.c
[ ... ]
> @@ -114,18 +114,12 @@ struct debuginfo *debuginfo__new(const char *path)
>  	dso__find_dbginfo_type(dso);
>  	if (dso__read_binary_type_filename(dso, dso__dbginfo_type(dso), &nil,
>  					   buf, PATH_MAX) < 0)
> -		goto out;
> +		return NULL;
>  
>  	dinfo = __debuginfo__new(buf);
>  	dso__put(dso);
>  
> -out:
> -	if (dinfo)
> -		return dinfo;
> -
> -	/* if failed to open all distro debuginfo, open given binary */
> -	symbol__join_symfs(buf, path);
> -	return __debuginfo__new(buf);

[Severity: High]
Does removing this fallback break DWARF support for files using alternative
debug sections like .gnu_debugdata (mini-debuginfo) or .zdebug_info?

The new logic entirely relies on dso__find_dbginfo_type() successfully
returning a binary type. However, dso__find_dbginfo_type() strictly
validates the file by exact string match:

tools/perf/util/dso.c:dso__find_dbginfo_type() {
	...
		if (filename__has_section(buf, ".debug_info"))
			break;
	...
}

Because files relying on .gnu_debugdata or .zdebug_info do not have a section
named exactly ".debug_info", this check fails. The type then defaults to
DSO_BINARY_TYPE__NOT_FOUND, and debuginfo__new() returns NULL.

Could this cause features like inline callchain resolution to silently fail on
these binaries since we completely bypass libdw's native support for parsing
these alternative formats?

> +	return dinfo;
>  }

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260928055055.95144-1-namhyung@kernel.org?part=3