bpf: libbpf: retry loading program on EAGAIN

Commit c3494801cd17 ("bpf: check pending signals while
verifying programs") makes it possible for the BPF_PROG_LOAD
to fail with EAGAIN. Retry unconditionally in this case.

Fixes: c3494801cd17 ("bpf: check pending signals while verifying programs")
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index 3caaa34..88cbd11 100644 (file)
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -65,6 +65,17 @@ static inline int sys_bpf(enum bpf_cmd cmd, union bpf_attr *attr,
        return syscall(__NR_bpf, cmd, attr, size);
 }
 
+static inline int sys_bpf_prog_load(union bpf_attr *attr, unsigned int size)
+{
+       int fd;
+
+       do {
+               fd = sys_bpf(BPF_PROG_LOAD, attr, size);
+       } while (fd < 0 && errno == EAGAIN);
+
+       return fd;
+}
+
 int bpf_create_map_xattr(const struct bpf_create_map_attr *create_attr)
 {
        __u32 name_len = create_attr->name ? strlen(create_attr->name) : 0;
@@ -232,7 +243,7 @@ int bpf_load_program_xattr(const struct bpf_load_program_attr *load_attr,
        memcpy(attr.prog_name, load_attr->name,
               min(name_len, BPF_OBJ_NAME_LEN - 1));
 
-       fd = sys_bpf(BPF_PROG_LOAD, &attr, sizeof(attr));
+       fd = sys_bpf_prog_load(&attr, sizeof(attr));
        if (fd >= 0)
                return fd;
 
@@ -269,7 +280,7 @@ int bpf_load_program_xattr(const struct bpf_load_program_attr *load_attr,
                        break;
                }
 
-               fd = sys_bpf(BPF_PROG_LOAD, &attr, sizeof(attr));
+               fd = sys_bpf_prog_load(&attr, sizeof(attr));
 
                if (fd >= 0)
                        goto done;
@@ -283,7 +294,7 @@ int bpf_load_program_xattr(const struct bpf_load_program_attr *load_attr,
        attr.log_size = log_buf_sz;
        attr.log_level = 1;
        log_buf[0] = 0;
-       fd = sys_bpf(BPF_PROG_LOAD, &attr, sizeof(attr));
+       fd = sys_bpf_prog_load(&attr, sizeof(attr));
 done:
        free(finfo);
        free(linfo);
@@ -328,7 +339,7 @@ int bpf_verify_program(enum bpf_prog_type type, const struct bpf_insn *insns,
        attr.kern_version = kern_version;
        attr.prog_flags = prog_flags;
 
-       return sys_bpf(BPF_PROG_LOAD, &attr, sizeof(attr));
+       return sys_bpf_prog_load(&attr, sizeof(attr));
 }
 
 int bpf_map_update_elem(int fd, const void *key, const void *value,