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BUG: KMSAN: uninit-value in virtio_net_hdr_to_skb+0x1414/0x14f0 include/linux/virtio_net.h:86
CPU: 0 PID: 31449 Comm: syz-executor.5 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]
 kernel_sendmsg+0x22c/0x2f0 net/socket.c:694
 sock_no_sendpage+0x205/0x2b0 net/core/sock.c:2860
 kernel_sendpage+0x47a/0x590 net/socket.c:3631
 sock_sendpage+0x161/0x1a0 net/socket.c:947
 pipe_to_sendpage+0x3e4/0x520 fs/splice.c:364
 splice_from_pipe_feed fs/splice.c:418 [inline]
 __splice_from_pipe+0x5e3/0xff0 fs/splice.c:562
 splice_from_pipe fs/splice.c:597 [inline]
 generic_splice_sendpage+0x1d5/0x2c0 fs/splice.c:746
 do_splice_from fs/splice.c:767 [inline]
 do_splice+0x23c3/0x2c10 fs/splice.c:1079
 __do_splice fs/splice.c:1144 [inline]
 __do_sys_splice fs/splice.c:1350 [inline]
 __se_sys_splice+0x8fa/0xb50 fs/splice.c:1332
 __x64_sys_splice+0x6e/0x90 fs/splice.c:1332
 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:00007fe927349188 EFLAGS: 00000246 ORIG_RAX: 0000000000000113
RAX: ffffffffffffffda RBX: 000000000056c0f0 RCX: 00000000004665d9
RDX: 0000000000000005 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00000000004bfcb9 R08: 000000000004ffe0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c0f0
R13: 0000000000a9fb1f R14: 00007fe927349300 R15: 0000000000022000

Uninit was created at:
 kmsan_save_stack_with_flags+0x3c/0x90 mm/kmsan/kmsan.c:121
 kmsan_alloc_page+0xd0/0x1e0 mm/kmsan/kmsan_shadow.c:274
 __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]
 stack_depot_save+0x402/0x4c0 lib/stackdepot.c:325
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:127 [inline]
 kmsan_internal_chain_origin+0xc6/0x130 mm/kmsan/kmsan.c:289
 kmsan_memcpy_memmove_metadata+0x25e/0x2d0 mm/kmsan/kmsan.c:226
 kmsan_memcpy_metadata+0xb/0x10 mm/kmsan/kmsan.c:246
 __msan_memcpy+0x46/0x60 mm/kmsan/kmsan_instr.c:110
 pskb_expand_head+0x4f5/0x1e20 net/core/skbuff.c:1687
 netlink_trim+0x3da/0x430 net/netlink/af_netlink.c:1294
 netlink_broadcast_filtered+0x14c/0x22f0 net/netlink/af_netlink.c:1499
 netlink_broadcast net/netlink/af_netlink.c:1544 [inline]
 nlmsg_multicast include/net/netlink.h:1033 [inline]
 nlmsg_notify+0x292/0x510 net/netlink/af_netlink.c:2545
 rtnl_notify net/core/rtnetlink.c:739 [inline]
 rtmsg_ifinfo_send net/core/rtnetlink.c:3818 [inline]
 rtmsg_ifinfo_event net/core/rtnetlink.c:3833 [inline]
 rtnetlink_event+0x33d/0x3b0 net/core/rtnetlink.c:5604
 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_mtu+0x241/0x390 net/core/dev.c:2124
 dev_set_mtu_ext+0xa0f/0xc60 net/core/dev.c:8828
 do_setlink+0xe92/0x7890 net/core/rtnetlink.c:2671
 rtnl_setlink+0x7f8/0x860 net/core/rtnetlink.c:3006
 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]
 sock_write_iter+0x585/0x680 net/socket.c:1001
 do_iter_readv_writev+0xa99/0xc30 include/linux/fs.h:1971
 do_iter_write+0x371/0x1090 fs/read_write.c:866
 vfs_writev fs/read_write.c:939 [inline]
 do_writev+0x55a/0xcf0 fs/read_write.c:982
 __do_sys_writev fs/read_write.c:1055 [inline]
 __se_sys_writev+0x9b/0xb0 fs/read_write.c:1052
 __x64_sys_writev+0x4a/0x70 fs/read_write.c:1052
 do_syscall_64+0x9f/0x140 arch/x86/entry/common.c:48
 entry_SYSCALL_64_after_hwframe+0x44/0xae
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