The flags in link_create no used in multi_kprobe, return -EINVAL if
they assigned, keep it same as other link attach apis. Perhaps due to
their usage habits, users may set the target_fd to -1. Therefore, no
check is carried out here, and it is kept consistent with the multi_uprobe.
Fixes: 0dcac2725406 ("bpf: Add multi kprobe link")
Signed-off-by: Tao Chen <chen.dylane@xxxxxxxxx>
---
kernel/trace/bpf_trace.c | 6 ++++++
1 file changed, 6 insertions(+)
Change list:
- v1 -> v2:
- remove target_fd check suggested by jiri.
- v1:
https://lore.kernel.org/bpf/20250331094745.336010-1-chen.dylane@xxxxxxxxx/
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 13bef2462..5cd0af80f 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -2992,6 +2992,12 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
/* no support for 32bit archs yet */
if (sizeof(u64) != sizeof(void *))
return -EOPNOTSUPP;
+ /*
+ * Perhaps due to their usage habits, users may set the target_fd to -1. Therefore,
+ * no check is carried out here, and it is kept consistent with the multi_uprobe.
+ */
+ if (attr->link_create.flags)
+ return -EINVAL;
if (!is_kprobe_multi(prog))
return -EINVAL;
--
2.43.0
