If the struct_ops is already attached, we should bail out or we will end up in various locks and pointer issues while unregistering. Signed-off-by: Benjamin Tissoires <bentiss@xxxxxxxxxx> --- drivers/hid/bpf/hid_bpf_struct_ops.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/hid/bpf/hid_bpf_struct_ops.c b/drivers/hid/bpf/hid_bpf_struct_ops.c index f59cce6e437f..cd696c59ba0f 100644 --- a/drivers/hid/bpf/hid_bpf_struct_ops.c +++ b/drivers/hid/bpf/hid_bpf_struct_ops.c @@ -183,6 +183,10 @@ static int hid_bpf_reg(void *kdata, struct bpf_link *link) struct hid_device *hdev; int count, err = 0; + /* prevent multiple attach of the same struct_ops */ + if (ops->hdev) + return -EINVAL; + hdev = hid_get_device(ops->hid_id); if (IS_ERR(hdev)) return PTR_ERR(hdev); @@ -248,6 +252,7 @@ static void hid_bpf_unreg(void *kdata, struct bpf_link *link) list_del_rcu(&ops->list); synchronize_srcu(&hdev->bpf.srcu); + ops->hdev = NULL; reconnect = hdev->bpf.rdesc_ops == ops; if (reconnect) -- 2.44.0
