[PATCHv7 bpf-next 03/15] bpf: Allow return values 0 and 1 for kprobe session

[Jiri Olsa <jolsa@xxxxxxxxxx>]

The kprobe session program can return only 0 or 1,
instruct verifier to check for that.

Fixes: 535a3692ba72 ("bpf: Add support for kprobe session attach")
Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
---
 kernel/bpf/verifier.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index f514247ba8ba..5c941fd1b141 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -15915,6 +15915,15 @@ static int check_return_code(struct bpf_verifier_env *env, int regno, const char
 			return -ENOTSUPP;
 		}
 		break;
+	case BPF_PROG_TYPE_KPROBE:
+		switch (env->prog->expected_attach_type) {
+		case BPF_TRACE_KPROBE_SESSION:
+			range = retval_range(0, 1);
+			break;
+		default:
+			return 0;
+		}
+		break;
 	case BPF_PROG_TYPE_SK_LOOKUP:
 		range = retval_range(SK_DROP, SK_PASS);
 		break;
-- 
2.46.2