On Mon, Sep 30, 2024 at 02:36:28PM -0700, Andrii Nakryiko wrote:

On Sun, Sep 29, 2024 at 1:58 PM Jiri Olsa [off-list ref] wrote:

quoted

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

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 kernel/bpf/verifier.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

Do we need Fixes: tag?

right, for kprobe session, will add

thanks,
jirka

Acked-by: Andrii Nakryiko <andrii@kernel.org>

quoted

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 7d9b38ffd220..c4d7b7369259 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c

@@ -15910,6 +15910,16 @@ 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:
+               case BPF_TRACE_UPROBE_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;
--

2.46.1