[PATCH 5.17 0550/1126] bpftool: Fix pretty print dump for maps without BTF loaded

Greg Kroah-Hartman
2022-04-05T09:08:17Z

From: Jiri Olsa <jolsa@kernel.org>

[ Upstream commit f76d8507d23834f7e56b0fe95c82605e7d7e0efe ]

The commit e5043894b21f ("bpftool: Use libbpf_get_error() to check error")
fails to dump map without BTF loaded in pretty mode (-p option).

Fixing this by making sure get_map_kv_btf won't fail in case there's
no BTF available for the map.

Fixes: e5043894b21f ("bpftool: Use libbpf_get_error() to check error")
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220216092102.125448-1-jolsa@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
tools/bpf/bpftool/map.c | 31 +++++++++++++++----------------
1 file changed, 15 insertions(+), 16 deletions(-)

diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c
index 7a341a472ea4..e746642de292 100644
--- a/tools/bpf/bpftool/map.c
+++ b/tools/bpf/bpftool/map.c
@@ -805,29 +805,30 @@ static int maps_have_btf(int *fds, int nb_fds)

static struct btf *btf_vmlinux;

-static struct btf *get_map_kv_btf(const struct bpf_map_info *info)
+static int get_map_kv_btf(const struct bpf_map_info *info, struct btf **btf)
{
- struct btf *btf = NULL;
+ int err = 0;

if (info->btf_vmlinux_value_type_id) {
if (!btf_vmlinux) {
btf_vmlinux = libbpf_find_kernel_btf();
- if (libbpf_get_error(btf_vmlinux))
+ err = libbpf_get_error(btf_vmlinux);
+ if (err) {
p_err("failed to get kernel btf");
+ return err;
+ }
}
- return btf_vmlinux;
+ *btf = btf_vmlinux;
} else if (info->btf_value_type_id) {
- int err;
-
- btf = btf__load_from_kernel_by_id(info->btf_id);
- err = libbpf_get_error(btf);
- if (err) {
+ *btf = btf__load_from_kernel_by_id(info->btf_id);
+ err = libbpf_get_error(*btf);
+ if (err)
p_err("failed to get btf");
- btf = ERR_PTR(err);
- }
+ } else {
+ *btf = NULL;
}

- return btf;
+ return err;
}

static void free_map_kv_btf(struct btf *btf)
@@ -862,8 +863,7 @@ map_dump(int fd, struct bpf_map_info *info, json_writer_t *wtr,
prev_key = NULL;

if (wtr) {
- btf = get_map_kv_btf(info);
- err = libbpf_get_error(btf);
+ err = get_map_kv_btf(info, &btf);
if (err) {
goto exit_free;
}
@@ -1054,8 +1054,7 @@ static void print_key_value(struct bpf_map_info *info, void *key,
json_writer_t *btf_wtr;
struct btf *btf;

- btf = get_map_kv_btf(info);
- if (libbpf_get_error(btf))
+ if (get_map_kv_btf(info, &btf))
return;

if (json_output) {
--
2.34.1