=====================================================
BUG: KMSAN: uninit-value in virtio_net_hdr_to_skb+0x1414/0x14f0 include/linux/virtio_net.h:86
CPU: 0 PID: 9327 Comm: syz-executor.1 Not tainted 5.12.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x24c/0x2e0 lib/dump_stack.c:120
 kmsan_report+0xfb/0x1e0 mm/kmsan/kmsan_report.c:121
 __msan_warning+0x5c/0xa0 mm/kmsan/kmsan_instr.c:197
 virtio_net_hdr_to_skb+0x1414/0x14f0 include/linux/virtio_net.h:86
 packet_snd net/packet/af_packet.c:2994 [inline]
 packet_sendmsg+0x85b8/0x99d0 net/packet/af_packet.c:3031
 sock_sendmsg_nosec net/socket.c:654 [inline]
 sock_sendmsg net/socket.c:674 [inline]
 sock_write_iter+0x585/0x680 net/socket.c:1001
 call_write_iter include/linux/fs.h:1977 [inline]
 aio_write+0x833/0xad0 fs/aio.c:1581
 __io_submit_one fs/aio.c:1840 [inline]
 io_submit_one+0x1d1a/0x4230 fs/aio.c:1883
 __do_sys_io_submit fs/aio.c:1942 [inline]
 __se_sys_io_submit+0x35b/0x7a0 fs/aio.c:1912
 __x64_sys_io_submit+0x4a/0x70 fs/aio.c:1912
 do_syscall_64+0x9f/0x140 arch/x86/entry/common.c:48
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x4665d9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fbc0141d188 EFLAGS: 00000246 ORIG_RAX: 00000000000000d1
RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665d9
RDX: 0000000020000080 RSI: 0000000000000001 RDI: 00007fbc013fc000
RBP: 00000000004bfcb9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf80
R13: 0000000000a9fb1f R14: 00007fbc0141d300 R15: 0000000000022000

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:120 [inline]
 kmsan_internal_poison_shadow+0x66/0xd0 mm/kmsan/kmsan.c:103
 kmsan_slab_alloc+0x8e/0xe0 mm/kmsan/kmsan_hooks.c:76
 slab_alloc_node mm/slub.c:2922 [inline]
 slab_alloc mm/slub.c:2931 [inline]
 kmem_cache_alloc_trace+0x8c7/0x1030 mm/slub.c:2948
 kmalloc include/linux/slab.h:554 [inline]
 __hw_addr_create_ex net/core/dev_addr_lists.c:30 [inline]
 __hw_addr_add_ex net/core/dev_addr_lists.c:76 [inline]
 __dev_mc_add+0x3a7/0x980 net/core/dev_addr_lists.c:775
 dev_mc_add+0x6d/0x80 net/core/dev_addr_lists.c:792
 igmp6_group_added+0x348/0xdc0 net/ipv6/mcast.c:669
 __ipv6_dev_mc_inc+0x11be/0x1570 net/ipv6/mcast.c:928
 ipv6_dev_mc_inc+0x70/0x80 net/ipv6/mcast.c:935
 ipv6_add_dev+0x14e4/0x1b60 net/ipv6/addrconf.c:458
 addrconf_notify+0xd44/0x6540 net/ipv6/addrconf.c:3491
 notifier_call_chain kernel/notifier.c:83 [inline]
 raw_notifier_call_chain+0x123/0x290 kernel/notifier.c:410
 call_netdevice_notifiers_info net/core/dev.c:2075 [inline]
 call_netdevice_notifiers_extack net/core/dev.c:2087 [inline]
 call_netdevice_notifiers net/core/dev.c:2101 [inline]
 register_netdevice+0x306f/0x3710 net/core/dev.c:10238
 veth_newlink+0xb5d/0x15c0 drivers/net/veth.c:1384
 __rtnl_newlink net/core/rtnetlink.c:3443 [inline]
 rtnl_newlink+0x2ecc/0x3d80 net/core/rtnetlink.c:3491
 rtnetlink_rcv_msg+0x143b/0x18e0 net/core/rtnetlink.c:5553
 netlink_rcv_skb+0x6fa/0x810 net/netlink/af_netlink.c:2502
 rtnetlink_rcv+0x50/0x60 net/core/rtnetlink.c:5571
 netlink_unicast_kernel net/netlink/af_netlink.c:1312 [inline]
 netlink_unicast+0x11d6/0x14a0 net/netlink/af_netlink.c:1338
 netlink_sendmsg+0x1740/0x1840 net/netlink/af_netlink.c:1927
 sock_sendmsg_nosec net/socket.c:654 [inline]
 sock_sendmsg net/socket.c:674 [inline]
 __sys_sendto+0x9ea/0xc60 net/socket.c:1977
 __do_sys_sendto net/socket.c:1989 [inline]
 __se_sys_sendto+0x107/0x130 net/socket.c:1985
 __x64_sys_sendto+0x6e/0x90 net/socket.c:1985
 do_syscall_64+0x9f/0x140 arch/x86/entry/common.c:48
 entry_SYSCALL_64_after_hwframe+0x44/0xae
=====================================================