[PATCH 07/12] perf tools: Check maps for bpf programs

Jiri Olsa
2019-04-16T16:02:01Z

From: Song Liu <songliubraving@fb.com>

As reported by Jiri Olsa in:

"[BUG] perf: intel_pt won't display kernel function"
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@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Yonghong Song <yhs@fb.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Fixes: 76193a94522f ("perf, bpf: Introduce PERF_RECORD_KSYMBOL")
Link: https://lore.kernel.org/lkml/20190403145353.GE32553@kernel.org

Signed-off-by: Song Liu <songliubraving@fb.com>
Link: http://lkml.kernel.org/n/tip-gnffkcoc4nauqcpgvsmwka2w@git.kernel.org
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
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 == 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 = map->dso->short_name;
+ return name && (strstr(name, "bpf_prog_") == 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..dc93787c74f0 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);
--
2.17.2