linux-kernel - Re: [PATCH v6 8/8] perf buildid-cache: recognize vdso when adding files

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Message-ID: <68f29f30-f0f8-4cda-a99a-68f51838dcd7@intel.com>
Date: Wed, 11 Sep 2024 11:05:20 +0300
From: Adrian Hunter <adrian.hunter@...el.com>
To: Changbin Du <changbin.du@...wei.com>,
 Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>,
 Arnaldo Carvalho de Melo <acme@...nel.org>,
 Namhyung Kim <namhyung@...nel.org>, Nathan Chancellor <nathan@...nel.org>
Cc: Mark Rutland <mark.rutland@....com>,
 Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
 Jiri Olsa <jolsa@...nel.org>, Ian Rogers <irogers@...gle.com>,
 "Liang, Kan" <kan.liang@...ux.intel.com>,
 Nick Desaulniers <ndesaulniers@...gle.com>, Bill Wendling
 <morbo@...gle.com>, Justin Stitt <justinstitt@...gle.com>,
 linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org,
 llvm@...ts.linux.dev, Hui Wang <hw.huiwang@...wei.com>
Subject: Re: [PATCH v6 8/8] perf buildid-cache: recognize vdso when adding
 files

On 25/07/24 05:15, Changbin Du wrote:
> Identify vdso by file name matching. The vdso objects have name
> as vdso[32,64].so[.dbg].
> 
> $ perf buildid-cache -a /work/linux/arch/x86/entry/vdso/vdso64.so.dbg
> 
> Without this change, adding vdso using above command actually will never
> be used.
> 
> Signed-off-by: Changbin Du <changbin.du@...wei.com>

A couple of comments, but address those then add:

Reviewed-by: Adrian Hunter <adrian.hunter@...el.com>

> ---
>  tools/perf/builtin-buildid-cache.c | 26 +++++++++++++++++++++++++-
>  1 file changed, 25 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/perf/builtin-buildid-cache.c b/tools/perf/builtin-buildid-cache.c
> index b0511d16aeb6..8edea9044a65 100644
> --- a/tools/perf/builtin-buildid-cache.c
> +++ b/tools/perf/builtin-buildid-cache.c
> @@ -172,6 +172,30 @@ static int build_id_cache__add_kcore(const char *filename, bool force)
>  	return 0;
>  }
>  
> +static bool filename_is_vdso(const char *filename)
> +{
> +	char *fname, *bname;
> +	static const char * const vdso_names[] = {
> +		"vdso.so", "vdso32.so", "vdso64.so", "vdsox32.so"
> +	};
> +
> +	fname = strdup(filename);
> +	if (!fname) {
> +		pr_err("no mememory\n");

mememory -> memory

> +		return false;
> +	}

fname is never freed.

> +
> +	bname = basename(fname);
> +	if (!bname)
> +		return false;
> +
> +	for (unsigned int i = 0; i < ARRAY_SIZE(vdso_names); i++) {

'unsigned' is unnecessary

> +		if (!strncmp(bname, vdso_names[i], strlen(vdso_names[i])))

Use strstarts()

> +			return true;
> +	}
> +	return false;
> +}
> +
>  static int build_id_cache__add_file(const char *filename, struct nsinfo *nsi)
>  {
>  	char sbuild_id[SBUILD_ID_SIZE];
> @@ -189,7 +213,7 @@ static int build_id_cache__add_file(const char *filename, struct nsinfo *nsi)
>  
>  	build_id__sprintf(&bid, sbuild_id);
>  	err = build_id_cache__add_s(sbuild_id, filename, nsi,
> -				    false, false);
> +				    false, filename_is_vdso(filename));
>  	pr_debug("Adding %s %s: %s\n", sbuild_id, filename,
>  		 err ? "FAIL" : "Ok");
>  	return err;