Re: [PATCH 12/25] perf tools: Try to load vmlinux from buildid database

Arnaldo Carvalho de Melo
2020-11-26T17:50:27Z

Em Thu, Nov 26, 2020 at 06:00:13PM +0100, Jiri Olsa escreveu:
> Currently we don't check on kernel's vmlinux the same way as
> we do for normal binaries, but we either look for kallsyms
> file in build id database or check on known vmlinux locations
> (plus some other optional paths).
>
> This patch adds the check for standard build id binary location,
> so we are ready once we start to store it there from debuginfod
> in following changes.

Thanks, applied.

- Arnaldo

> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> ---
> tools/perf/util/build-id.c | 13 ++++++++++---
> tools/perf/util/build-id.h | 2 ++
> tools/perf/util/symbol.c | 16 ++++++++++++++++
> 3 files changed, 28 insertions(+), 3 deletions(-)
>
> diff --git a/tools/perf/util/build-id.c b/tools/perf/util/build-id.c
> index 4a391f13f40d..1fd58703c2d4 100644
> --- a/tools/perf/util/build-id.c
> +++ b/tools/perf/util/build-id.c
> @@ -261,10 +261,9 @@ static const char *build_id_cache__basename(bool is_kallsyms, bool is_vdso,
> "debug" : "elf"));
> }
>
> -char *dso__build_id_filename(const struct dso *dso, char *bf, size_t size,
> - bool is_debug)
> +char *__dso__build_id_filename(const struct dso *dso, char *bf, size_t size,
> + bool is_debug, bool is_kallsyms)
> {
> - bool is_kallsyms = dso__is_kallsyms((struct dso *)dso);
> bool is_vdso = dso__is_vdso((struct dso *)dso);
> char sbuild_id[SBUILD_ID_SIZE];
> char *linkname;
> @@ -293,6 +292,14 @@ char *dso__build_id_filename(const struct dso *dso, char *bf, size_t size,
> return bf;
> }
>
> +char *dso__build_id_filename(const struct dso *dso, char *bf, size_t size,
> + bool is_debug)
> +{
> + bool is_kallsyms = dso__is_kallsyms((struct dso *)dso);
> +
> + return __dso__build_id_filename(dso, bf, size, is_debug, is_kallsyms);
> +}
> +
> #define dsos__for_each_with_build_id(pos, head) \
> list_for_each_entry(pos, head, node) \
> if (!pos->has_build_id) \
> diff --git a/tools/perf/util/build-id.h b/tools/perf/util/build-id.h
> index d53415feaf69..f1a2f67df6e4 100644
> --- a/tools/perf/util/build-id.h
> +++ b/tools/perf/util/build-id.h
> @@ -29,6 +29,8 @@ char *build_id_cache__kallsyms_path(const char *sbuild_id, char *bf,
>
> char *dso__build_id_filename(const struct dso *dso, char *bf, size_t size,
> bool is_debug);
> +char *__dso__build_id_filename(const struct dso *dso, char *bf, size_t size,
> + bool is_debug, bool is_kallsyms);
>
> int build_id__mark_dso_hit(struct perf_tool *tool, union perf_event *event,
> struct perf_sample *sample, struct evsel *evsel,
> diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
> index 0d14abdf3d72..64a039cbba1b 100644
> --- a/tools/perf/util/symbol.c
> +++ b/tools/perf/util/symbol.c
> @@ -2189,6 +2189,8 @@ static int dso__load_kernel_sym(struct dso *dso, struct map *map)
> int err;
> const char *kallsyms_filename = NULL;
> char *kallsyms_allocated_filename = NULL;
> + char *filename = NULL;
> +
> /*
> * Step 1: if the user specified a kallsyms or vmlinux filename, use
> * it and only it, reporting errors to the user if it cannot be used.
> @@ -2213,6 +2215,20 @@ static int dso__load_kernel_sym(struct dso *dso, struct map *map)
> return dso__load_vmlinux(dso, map, symbol_conf.vmlinux_name, false);
> }
>
> + /*
> + * Before checking on common vmlinux locations, check if it's
> + * stored as standard build id binary (not kallsyms) under
> + * .debug cache.
> + */
> + if (!symbol_conf.ignore_vmlinux_buildid)
> + filename = __dso__build_id_filename(dso, NULL, 0, false, false);
> + if (filename != NULL) {
> + err = dso__load_vmlinux(dso, map, filename, true);
> + if (err > 0)
> + return err;
> + free(filename);
> + }
> +
> if (!symbol_conf.ignore_vmlinux && vmlinux_path != NULL) {
> err = dso__load_vmlinux_path(dso, map);
> if (err > 0)
> --
> 2.26.2
>

--

- Arnaldo