Before this patch, a program with unspecified type
(BPF_PROG_TYPE_UNSPEC) would be passed to the BPF syscall, only to have
the kernel reject it with an opaque invalid argument error. This patch
makes libbpf reject such programs with a nicer error message - in
particular libbpf now tries to diagnose bad ELF section names at both
open time and load time.
Signed-off-by: Andrei Matei <andreimatei1@xxxxxxxxx>
---
v3: fixup tabs/spaces screwup in v2
tools/lib/bpf/libbpf.c | 15 ++++++++++++++-
1 file changed, 14 insertions(+), 1 deletion(-)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 313034117070..d6f45538444d 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -6629,6 +6629,16 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt,
char *log_buf = NULL;
int btf_fd, ret;
+ if (prog->type == BPF_PROG_TYPE_UNSPEC) {
+ /*
+ * The program type must be set. Most likely we couldn't find a proper
+ * section definition at load time, and thus we didn't infer the type.
+ */
+ pr_warn("prog '%s': missing BPF prog type, check ELF section name '%s'\n",
+ prog->name, prog->sec_name);
+ return -EINVAL;
+ }
+
if (!insns || !insns_cnt)
return -EINVAL;
@@ -6920,9 +6930,12 @@ __bpf_object__open(const char *path, const void *obj_buf, size_t obj_buf_sz,
bpf_object__for_each_program(prog, obj) {
prog->sec_def = find_sec_def(prog->sec_name);
- if (!prog->sec_def)
+ if (!prog->sec_def) {
/* couldn't guess, but user might manually specify */
+ pr_debug("prog '%s': unrecognized ELF section name '%s'\n",
+ prog->name, prog->sec_name);
continue;
+ }
if (prog->sec_def->is_sleepable)
prog->prog_flags |= BPF_F_SLEEPABLE;
--
2.27.0
