Re: [syzbot] [bpf?] [net?] general protection fault in dev_map_enqueue

[Edward Adam Davis <eadavis@qq.com>]

please test null ptr deref in dev_map_enqueue

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git 443574b03387

diff --git a/net/core/filter.c b/net/core/filter.c
index 8adf95765cdd..721b85aebf58 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -4381,6 +4381,10 @@ static __always_inline int __xdp_do_redirect_frame(struct bpf_redirect_info *ri,
 			err = dev_map_enqueue_multi(xdpf, dev, map,
 						    ri->flags & BPF_F_EXCLUDE_INGRESS);
 		} else {
+			if (unlikely(!fwd)) {
+				err = -EINVAL;
+				break;
+			}
 			err = dev_map_enqueue(fwd, xdpf, dev);
 		}
 		break;