Hi, all!

In the linux-next tree, next-20241108, coccinelle found an error.

In the line 617, ret = bpf_skb_set_tunnel_opt(skb, gopt, sizeof(local_gopt)); In the line 678, ret = bpf_skb_set_tunnel_opt(skb, gopt, sizeof(gopt));

when

592 struct local_geneve_opt local_gopt; 593 struct geneve_opt *gopt = (struct geneve_opt *) &local_gopt;

and

652 struct local_geneve_opt local_gopt; 653 struct geneve_opt *gopt = (struct geneve_opt *) &local_gopt;

So, in all other call to bpf_skb_set_tunnel_opt(), the third parameter is the size of the struct, not the size of the pointer:

./tools/testing/selftests/bpf/progs/test_tunnel_kern.c:193: ret = bpf_skb_set_tunnel_opt(skb, &md, sizeof(md)); ./tools/testing/selftests/bpf/progs/test_tunnel_kern.c:273: ret = bpf_skb_set_tunnel_opt(skb, &md, sizeof(md)); ./tools/testing/selftests/bpf/progs/test_tunnel_kern.c:349: ret = bpf_skb_set_tunnel_opt(skb, &md, sizeof(md)); ./tools/testing/selftests/bpf/progs/test_tunnel_kern.c:388: ret = bpf_skb_set_tunnel_opt(skb, &md, sizeof(md)); ./tools/testing/selftests/bpf/progs/test_tunnel_kern.c:617: ret = bpf_skb_set_tunnel_opt(skb, gopt, sizeof(local_gopt)); ./tools/testing/selftests/bpf/progs/test_tunnel_kern.c:678: ret = bpf_skb_set_tunnel_opt(skb, gopt, sizeof(gopt));

===========================================

587 SEC("tc") 588 int geneve_set_tunnel(struct __sk_buff *skb) 589 { 590 int ret; 591 struct bpf_tunnel_key key; 592 struct local_geneve_opt local_gopt; 593 struct geneve_opt *gopt = (struct geneve_opt *) &local_gopt; 594 595 __builtin_memset(&key, 0x0, sizeof(key)); 596 key.remote_ipv4 = 0xac100164; /* 172.16.1.100 */ 597 key.tunnel_id = 2; 598 key.tunnel_tos = 0; 599 key.tunnel_ttl = 64; 600 601 __builtin_memset(gopt, 0x0, sizeof(local_gopt)); 602 gopt->opt_class = bpf_htons(0x102); /* Open Virtual Networking (OVN) */ 603 gopt->type = 0x08; 604 gopt->r1 = 0; 605 gopt->r2 = 0; 606 gopt->r3 = 0; 607 gopt->length = 2; /* 4-byte multiple */ 608 *(int *) &gopt->opt_data = bpf_htonl(0xdeadbeef); 609 610 ret = bpf_skb_set_tunnel_key(skb, &key, sizeof(key), 611 BPF_F_ZERO_CSUM_TX); 612 if (ret < 0) { 613 log_err(ret); 614 return TC_ACT_SHOT; 615 } 616 617 → ret = bpf_skb_set_tunnel_opt(skb, gopt, sizeof(local_gopt)); 618 if (ret < 0) { 619 log_err(ret); 620 return TC_ACT_SHOT; 621 } 622 623 return TC_ACT_OK; 624 }

648 SEC("tc") 649 int ip6geneve_set_tunnel(struct __sk_buff *skb) 650 { 651 struct bpf_tunnel_key key; 652 struct local_geneve_opt local_gopt; 653 struct geneve_opt *gopt = (struct geneve_opt *) &local_gopt; 654 int ret; 655 656 __builtin_memset(&key, 0x0, sizeof(key)); 657 key.remote_ipv6[3] = bpf_htonl(0x11); /* ::11 */ 658 key.tunnel_id = 22; 659 key.tunnel_tos = 0; 660 key.tunnel_ttl = 64; 661 662 ret = bpf_skb_set_tunnel_key(skb, &key, sizeof(key), 663 BPF_F_TUNINFO_IPV6); 664 if (ret < 0) { 665 log_err(ret); 666 return TC_ACT_SHOT; 667 } 668 669 __builtin_memset(gopt, 0x0, sizeof(local_gopt)); 670 gopt->opt_class = bpf_htons(0x102); /* Open Virtual Networking (OVN) */ 671 gopt->type = 0x08; 672 gopt->r1 = 0; 673 gopt->r2 = 0; 674 gopt->r3 = 0; 675 gopt->length = 2; /* 4-byte multiple */ 676 *(int *) &gopt->opt_data = bpf_htonl(0xfeedbeef); 677 678 → ret = bpf_skb_set_tunnel_opt(skb, gopt, sizeof(gopt)); 679 if (ret < 0) { 680 log_err(ret); 681 return TC_ACT_SHOT; 682 } 683 684 return TC_ACT_OK; 685 }

SOLUTION:

Fixes: 5ddafcc377f98 ("selftests/bpf: Fix a few tests for GCC related warnings.")

------------------ diff --git a/tools/testing/selftests/bpf/progs/test_tunnel_kern.c b/tools/testing/selftests/bpf/progs/test_tunnel_kern.c index 32127f1cd687..b53d367451b2 100644 --- a/tools/testing/selftests/bpf/progs/test_tunnel_kern.c +++ b/tools/testing/selftests/bpf/progs/test_tunnel_kern.c @@ -675,7 +675,7 @@ int ip6geneve_set_tunnel(struct __sk_buff *skb) gopt->length = 2; /* 4-byte multiple */ *(int *) &gopt->opt_data = bpf_htonl(0xfeedbeef);

- ret = bpf_skb_set_tunnel_opt(skb, gopt, sizeof(gopt)); + ret = bpf_skb_set_tunnel_opt(skb, gopt, sizeof(local_gopt)); if (ret < 0) { log_err(ret); return TC_ACT_SHOT; --

Best regards, MT