[PATCH bpf 1/2] libbpf: fix removal of inner map in bpf_object__create_map
From: Martynas Pumputis <hidden>
Date: 2021-07-19 17:39:14
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [library] (libbpf), the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Linus Torvalds
If creating an outer map of a BTF-defined map-in-map fails (via
bpf_object__create_map()), then the previously created its inner map
won't be destroyed.
Fix this by ensuring that the destroy routines are not bypassed in the
case of a failure.
Fixes: 646f02ffdd49c ("libbpf: Add BTF-defined map-in-map support")
Reported-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Martynas Pumputis <redacted>
---
tools/lib/bpf/libbpf.c | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 6f5e2757bb3c..dde521366579 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c@@ -4479,6 +4479,7 @@ static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map, b { struct bpf_create_map_attr create_attr; struct bpf_map_def *def = &map->def; + int err = 0; memset(&create_attr, 0, sizeof(create_attr));
@@ -4521,8 +4522,6 @@ static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map, b if (bpf_map_type__is_map_in_map(def->type)) { if (map->inner_map) { - int err; - err = bpf_object__create_map(obj, map->inner_map, true); if (err) { pr_warn("map '%s': failed to create inner map: %d\n",
@@ -4547,7 +4546,7 @@ static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map, b if (map->fd < 0 && (create_attr.btf_key_type_id || create_attr.btf_value_type_id)) { char *cp, errmsg[STRERR_BUFSIZE]; - int err = -errno; + err = -errno; cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg)); pr_warn("Error in bpf_create_map_xattr(%s):%s(%d). Retrying without BTF.\n",
@@ -4560,8 +4559,7 @@ static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map, b map->fd = bpf_create_map_xattr(&create_attr); } - if (map->fd < 0) - return -errno; + err = map->fd < 0 ? -errno : 0; if (bpf_map_type__is_map_in_map(def->type) && map->inner_map) { if (obj->gen_loader)
@@ -4570,7 +4568,7 @@ static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map, b zfree(&map->inner_map); } - return 0; + return err; } static int init_map_slots(struct bpf_object *obj, struct bpf_map *map)
--
2.32.0