4.20-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit 23499442c319412aa8e54e7a939e2eb531bdd77d ]
Since commit 88cda1c9da02 ("bpf: libbpf: Provide basic API support to specify BPF obj name"), libbpf unconditionally sets bpf_attr->name for maps. Pre v4.14 kernels don't know about map names and return an error about unexpected non-zero data. Retry sys_bpf without a map name to cover older kernels.
v2 changes: * check for errno == EINVAL as suggested by Daniel Borkmann
Signed-off-by: Stanislav Fomichev sdf@google.com Signed-off-by: Daniel Borkmann daniel@iogearbox.net Signed-off-by: Sasha Levin sashal@kernel.org --- tools/lib/bpf/bpf.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c index 03f9bcc4ef50..961e1b9fc592 100644 --- a/tools/lib/bpf/bpf.c +++ b/tools/lib/bpf/bpf.c @@ -69,6 +69,7 @@ int bpf_create_map_xattr(const struct bpf_create_map_attr *create_attr) { __u32 name_len = create_attr->name ? strlen(create_attr->name) : 0; union bpf_attr attr; + int ret;
memset(&attr, '\0', sizeof(attr));
@@ -86,7 +87,15 @@ int bpf_create_map_xattr(const struct bpf_create_map_attr *create_attr) attr.map_ifindex = create_attr->map_ifindex; attr.inner_map_fd = create_attr->inner_map_fd;
- return sys_bpf(BPF_MAP_CREATE, &attr, sizeof(attr)); + ret = sys_bpf(BPF_MAP_CREATE, &attr, sizeof(attr)); + if (ret < 0 && errno == EINVAL && create_attr->name) { + /* Retry the same syscall, but without the name. + * Pre v4.14 kernels don't support map names. + */ + memset(attr.map_name, 0, sizeof(attr.map_name)); + return sys_bpf(BPF_MAP_CREATE, &attr, sizeof(attr)); + } + return ret; }
int bpf_create_map_node(enum bpf_map_type map_type, const char *name,