[PATCH v3 2/4] perf bpf: check perf_attr_map is compatible with the perf binary

Song Liu
2021-04-16T22:13:55Z

perf_attr_map could be shared among different version of perf binary. Add
bperf_attr_map_compatible() to check whether the existing attr_map is
compatible with current perf binary.

Signed-off-by: Song Liu <song@kernel.org>
---
tools/perf/util/bpf_counter.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)

diff --git a/tools/perf/util/bpf_counter.c b/tools/perf/util/bpf_counter.c
index be484ddbbd5be..5de991ab46af9 100644
--- a/tools/perf/util/bpf_counter.c
+++ b/tools/perf/util/bpf_counter.c
@@ -312,6 +312,20 @@ static __u32 bpf_map_get_id(int fd)
return map_info.id;
}

+static bool bperf_attr_map_compatible(int attr_map_fd)
+{
+ struct bpf_map_info map_info = {0};
+ __u32 map_info_len = sizeof(map_info);
+ int err;
+
+ err = bpf_obj_get_info_by_fd(attr_map_fd, &map_info, &map_info_len);
+
+ if (err)
+ return false;
+ return (map_info.key_size == sizeof(struct perf_event_attr)) &&
+ (map_info.value_size == sizeof(struct perf_event_attr_map_entry));
+}
+
static int bperf_lock_attr_map(struct target *target)
{
char path[PATH_MAX];
@@ -346,6 +360,11 @@ static int bperf_lock_attr_map(struct target *target)
return -1;
}

+ if (!bperf_attr_map_compatible(map_fd)) {
+ close(map_fd);
+ return -1;
+
+ }
err = flock(map_fd, LOCK_EX);
if (err) {
close(map_fd);
--
2.30.2