=====================================================
BUG: KMSAN: uninit-value in virtio_net_hdr_to_skb+0x1414/0x14f0 include/linux/virtio_net.h:86
CPU: 0 PID: 22453 Comm: syz-executor.3 Tainted: G        W         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]
 ____sys_sendmsg+0xcfc/0x12f0 net/socket.c:2350
 ___sys_sendmsg net/socket.c:2404 [inline]
 __sys_sendmsg+0x714/0x830 net/socket.c:2433
 __compat_sys_sendmsg net/compat.c:347 [inline]
 __do_compat_sys_sendmsg net/compat.c:354 [inline]
 __se_compat_sys_sendmsg+0xa7/0xc0 net/compat.c:351
 __ia32_compat_sys_sendmsg+0x4a/0x70 net/compat.c:351
 do_syscall_32_irqs_on arch/x86/entry/common.c:79 [inline]
 __do_fast_syscall_32+0x127/0x180 arch/x86/entry/common.c:142
 do_fast_syscall_32+0x77/0xd0 arch/x86/entry/common.c:168
 do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:211
 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c
RIP: 0023:0xf7f14549
Code: 03 74 c0 01 10 05 03 74 b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00
RSP: 002b:00000000f550e5fc EFLAGS: 00000296 ORIG_RAX: 0000000000000172
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000020000440
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000

Uninit was created at:
 kmsan_save_stack_with_flags+0x3c/0x90 mm/kmsan/kmsan.c:120
 kmsan_alloc_page+0xd0/0x1e0 mm/kmsan/kmsan_shadow.c:273
 __alloc_pages_nodemask+0x827/0xf90 mm/page_alloc.c:5044
 alloc_pages_current+0x7b6/0xb60 mm/mempolicy.c:2277
 alloc_pages include/linux/gfp.h:561 [inline]
 skb_page_frag_refill+0x194/0x790 net/core/sock.c:2493
 sk_page_frag_refill+0xa3/0x3b0 net/core/sock.c:2513
 tcp_sendmsg_locked+0x3018/0x7c90 net/ipv4/tcp.c:1343
 tcp_sendmsg+0xb2/0x100 net/ipv4/tcp.c:1457
 inet6_sendmsg+0x15b/0x1d0 net/ipv6/af_inet6.c:642
 sock_sendmsg_nosec net/socket.c:654 [inline]
 sock_sendmsg net/socket.c:674 [inline]
 kernel_sendmsg+0x22c/0x2f0 net/socket.c:694
 rds_tcp_sendmsg net/rds/tcp_send.c:66 [inline]
 rds_tcp_xmit+0x783/0x15b0 net/rds/tcp_send.c:104
 rds_send_xmit+0x1509/0x3ea0 net/rds/send.c:367
 rds_send_worker+0xdf/0x3f0 net/rds/threads.c:200
 process_one_work+0x1219/0x1fe0 kernel/workqueue.c:2275
 worker_thread+0x10ec/0x2340 kernel/workqueue.c:2421
 kthread+0x521/0x560 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
=====================================================