| Message ID | 20180809155521.1544888-2-yhs@fb.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | BPF Maintainers |
| Headers | show |
| Series | bpf: add bpffs pretty print for hash/lru_hash maps | expand |
diff --git a/kernel/bpf/inode.c b/kernel/bpf/inode.c index 76efe9a183f5..fc5b103512e7 100644 --- a/kernel/bpf/inode.c +++ b/kernel/bpf/inode.c @@ -196,19 +196,21 @@ static void *map_seq_next(struct seq_file *m, void *v, loff_t *pos) { struct bpf_map *map = seq_file_to_map(m); void *key = map_iter(m)->key; + void *prev_key; if (map_iter(m)->done) return NULL; if (unlikely(v == SEQ_START_TOKEN)) - goto done; + prev_key = NULL; + else + prev_key = key; - if (map->ops->map_get_next_key(map, key, key)) { + if (map->ops->map_get_next_key(map, prev_key, key)) { map_iter(m)->done = true; return NULL; } -done: ++(*pos); return key; }
In function map_seq_next() of kernel/bpf/inode.c, the first key will be the "0" regardless of the map type. This works for array. But for hash type, if it happens key "0" is in the map, the bpffs map show will miss some items if the key "0" is not the first element of the first bucket. This patch fixed the issue by guaranteeing to get the first element, if the seq_show is just started, by passing NULL pointer key to map_get_next_key() callback. This way, no missing elements will occur for bpffs hash table show even if key "0" is in the map. Fixes: a26ca7c982cb5 ("bpf: btf: Add pretty print support to the basic arraymap") Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Yonghong Song <yhs@fb.com> --- kernel/bpf/inode.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)