From: Andrii Nakryiko <andrii@kernel.org>
To: <bpf@vger.kernel.org>, <netdev@vger.kernel.org>, <ast@fb.com>,
<daniel@iogearbox.net>
Cc: <andrii@kernel.org>, <kernel-team@fb.com>
Subject: [PATCH v2 bpf-next 2/2] libbpf: reject static maps
Date: Thu, 13 May 2021 16:36:43 -0700 [thread overview]
Message-ID: <20210513233643.194711-2-andrii@kernel.org> (raw)
In-Reply-To: <20210513233643.194711-1-andrii@kernel.org>
Static maps never really worked with libbpf, because all such maps were always
silently resolved to the very first map. Detect static maps (both legacy and
BTF-defined) and report user-friendly error.
Tested locally by switching few maps (legacy and BTF-defined) in selftests to
static ones and verifying that now libbpf rejects them loudly.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
v1->v2:
- remove accidentally added empty line; the deleted empty line on line 1798 is good.
tools/lib/bpf/libbpf.c | 24 +++++++++++++++++++-----
1 file changed, 19 insertions(+), 5 deletions(-)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index b8cf93fa1b4d..182bd3d3f728 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -1795,7 +1795,6 @@ static int bpf_object__init_user_maps(struct bpf_object *obj, bool strict)
if (!symbols)
return -EINVAL;
-
scn = elf_sec_by_idx(obj, obj->efile.maps_shndx);
data = elf_sec_data(obj, scn);
if (!scn || !data) {
@@ -1855,6 +1854,12 @@ static int bpf_object__init_user_maps(struct bpf_object *obj, bool strict)
return -LIBBPF_ERRNO__FORMAT;
}
+ if (GELF_ST_TYPE(sym.st_info) == STT_SECTION
+ || GELF_ST_BIND(sym.st_info) == STB_LOCAL) {
+ pr_warn("map '%s' (legacy): static maps are not supported\n", map_name);
+ return -ENOTSUP;
+ }
+
map->libbpf_type = LIBBPF_MAP_UNSPEC;
map->sec_idx = sym.st_shndx;
map->sec_offset = sym.st_value;
@@ -2262,6 +2267,16 @@ static void fill_map_from_def(struct bpf_map *map, const struct btf_map_def *def
pr_debug("map '%s': found inner map definition.\n", map->name);
}
+static const char *btf_var_linkage_str(__u32 linkage)
+{
+ switch (linkage) {
+ case BTF_VAR_STATIC: return "static";
+ case BTF_VAR_GLOBAL_ALLOCATED: return "global";
+ case BTF_VAR_GLOBAL_EXTERN: return "extern";
+ default: return "unknown";
+ }
+}
+
static int bpf_object__init_user_btf_map(struct bpf_object *obj,
const struct btf_type *sec,
int var_idx, int sec_idx,
@@ -2294,10 +2309,9 @@ static int bpf_object__init_user_btf_map(struct bpf_object *obj,
map_name, btf_kind_str(var));
return -EINVAL;
}
- if (var_extra->linkage != BTF_VAR_GLOBAL_ALLOCATED &&
- var_extra->linkage != BTF_VAR_STATIC) {
- pr_warn("map '%s': unsupported var linkage %u.\n",
- map_name, var_extra->linkage);
+ if (var_extra->linkage != BTF_VAR_GLOBAL_ALLOCATED) {
+ pr_warn("map '%s': unsupported map linkage %s.\n",
+ map_name, btf_var_linkage_str(var_extra->linkage));
return -EOPNOTSUPP;
}
--
2.30.2
next prev parent reply other threads:[~2021-05-13 23:36 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-13 23:36 [PATCH v2 bpf-next 1/2] selftests/bpf: validate skeleton gen handles skipped fields Andrii Nakryiko
2021-05-13 23:36 ` Andrii Nakryiko [this message]
2021-05-14 0:30 ` patchwork-bot+netdevbpf
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