[PATCH] perf util: check maps for bpf programs

[Song Liu]

As reported by Jiri Olsa in:

  "[BUG] perf: intel_pt won't display kernel function"
  20190403143738.GB32001@krava">https://lore.kernel.org/lkml/20190403143738.GB32001@krava

Recent changes to support PERF_RECORD_KSYMBOL and PERF_RECORD_BPF_EVENT
broke --kallsyms option. This is because it broke test __map__is_kmodule.

This patch fixes this by adding check for bpf program, so that these maps
are not mistaken as kernel modules.

Reported-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Alexei Starovoitov <ast@xxxxxxxxxx>
Cc: Andrii Nakryiko <andrii.nakryiko@xxxxxxxxx>
Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Cc: Martin KaFai Lau <kafai@xxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Song Liu <songliubraving@xxxxxx>
Cc: Yonghong Song <yhs@xxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Fixes: 76193a94522f ("perf, bpf: Introduce PERF_RECORD_KSYMBOL")
Link: https://lore.kernel.org/lkml/20190403145353.GE32553@xxxxxxxxxx

Signed-off-by: Song Liu <songliubraving@xxxxxx>
---
 tools/perf/util/map.c | 16 ++++++++++++++++
 tools/perf/util/map.h |  4 +++-
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index e32628cd20a7..28d484ef74ae 100644
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -261,6 +261,22 @@ bool __map__is_extra_kernel_map(const struct map *map)
        return kmap && kmap->name[0];
 }

+bool __map__is_bpf_prog(const struct map *map)
+{
+       const char *name;
+
+       if (map->dso->binary_type =3D=3D DSO_BINARY_TYPE__BPF_PROG_INFO)
+               return true;
+
+       /*
+        * If PERF_RECORD_BPF_EVENT is not included, the dso will not have
+        * type of DSO_BINARY_TYPE__BPF_PROG_INFO. In such cases, we can
+        * guess the type based on name.
+        */
+       name =3D map->dso->short_name;
+       return name && (strstr(name, "bpf_prog_") =3D=3D name);
+}
+
 bool map__has_symbols(const struct map *map)
 {
        return dso__has_symbols(map->dso);
diff --git a/tools/perf/util/map.h b/tools/perf/util/map.h
index 0e20749f2c55..01079f1f4375 100644
--- a/tools/perf/util/map.h
+++ b/tools/perf/util/map.h
@@ -159,10 +159,12 @@ int map__set_kallsyms_ref_reloc_sym(struct map *map, =
const char *symbol_name,

 bool __map__is_kernel(const struct map *map);
 bool __map__is_extra_kernel_map(const struct map *map);
+bool __map__is_bpf_prog(const struct map *map);

 static inline bool __map__is_kmodule(const struct map *map)
 {
-       return !__map__is_kernel(map) && !__map__is_extra_kernel_map(map);
+       return !__map__is_kernel(map) && !__map__is_extra_kernel_map(map) &=
&
+               !__map__is_bpf_prog(map);
 }

 bool map__has_symbols(const struct map *map);
--
2.17.1