From: Geliang Tang tanggeliang@kylinos.cn
Run bloom_filter_map selftests (./test_progs -t bloom_filter_map) on a Loongarch platform, an error message "JIT doesn't support bpf-to-bpf calls" is got in user space, together with an unexpected errno EINVAL (22), not ENOTSUPP (524):
libbpf: prog 'inner_map': BPF program load failed: Invalid argument libbpf: prog 'inner_map': -- BEGIN PROG LOAD LOG -- JIT doesn't support bpf-to-bpf calls callbacks are not allowed in non-JITed programs processed 37 insns (limit 1000000) max_states_per_insn 1 total_states -- END PROG LOAD LOG -- libbpf: prog 'inner_map': failed to load: -22 libbpf: failed to load object 'bloom_filter_map' libbpf: failed to load BPF skeleton 'bloom_filter_map': -22 setup_progs:FAIL:bloom_filter_map__open_and_load unexpected error: -22 #16 bloom_filter_map:FAIL
Although the return value of jit_subprogs() does be set as "ENOTSUPP":
verbose(env, "JIT doesn't support bpf-to-bpf calls\n"); err = -ENOTSUPP; goto out_free;
But afterwards in fixup_call_args(), the return value of jit_subprogs() is ignored, and overwritten as "-EINVAL":
verbose(env, "callbacks are not allowed in non-JITed programs\n"); return -EINVAL;
This patch fixes this by changing return values of fixup_call_args() from "-EINVAL" to "err ?: -EINVAL". With this change, errno 524 is got in user space now:
libbpf: prog 'inner_map': BPF program load failed: unknown error (-524) libbpf: prog 'inner_map': -- BEGIN PROG LOAD LOG -- JIT doesn't support bpf-to-bpf calls processed 37 insns (limit 1000000) max_states_per_insn 1 total_states -- END PROG LOAD LOG -- libbpf: prog 'inner_map': failed to load: -524 libbpf: failed to load object 'bloom_filter_map' libbpf: failed to load BPF skeleton 'bloom_filter_map': -524 setup_progs:FAIL:bloom_filter_map__open_and_load unexpected error: -524
Signed-off-by: Geliang Tang tanggeliang@kylinos.cn --- kernel/bpf/verifier.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index c0263fb5ca4b..aa589fedd036 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -19717,14 +19717,14 @@ static int fixup_call_args(struct bpf_verifier_env *env) #ifndef CONFIG_BPF_JIT_ALWAYS_ON if (has_kfunc_call) { verbose(env, "calling kernel functions are not allowed in non-JITed programs\n"); - return -EINVAL; + return err ?: -EINVAL; } if (env->subprog_cnt > 1 && env->prog->aux->tail_call_reachable) { /* When JIT fails the progs with bpf2bpf calls and tail_calls * have to be rejected, since interpreter doesn't support them yet. */ verbose(env, "tail_calls are not allowed in non-JITed programs with bpf-to-bpf calls\n"); - return -EINVAL; + return err ?: -EINVAL; } for (i = 0; i < prog->len; i++, insn++) { if (bpf_pseudo_func(insn)) { @@ -19732,7 +19732,7 @@ static int fixup_call_args(struct bpf_verifier_env *env) * have to be rejected, since interpreter doesn't support them yet. */ verbose(env, "callbacks are not allowed in non-JITed programs\n"); - return -EINVAL; + return err ?: -EINVAL; }
if (!bpf_pseudo_call(insn))