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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: 19822 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]
 sock_write_iter+0x585/0x680 net/socket.c:1001
 call_write_iter include/linux/fs.h:1977 [inline]
 new_sync_write fs/read_write.c:518 [inline]
 vfs_write+0x1083/0x1b00 fs/read_write.c:605
 ksys_write+0x275/0x500 fs/read_write.c:658
 __do_sys_write fs/read_write.c:670 [inline]
 __se_sys_write+0x92/0xb0 fs/read_write.c:667
 __x64_sys_write+0x4a/0x70 fs/read_write.c:667
 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:00007f36d032c188 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665d9
RDX: 0000000000000122 RSI: 00000000200003c0 RDI: 0000000000000003
RBP: 00000000004bfcb9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf80
R13: 0000000000a9fb1f R14: 00007f36d032c300 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]
 __kmalloc_track_caller+0x965/0x11f0 mm/slub.c:4578
 kmemdup+0x95/0x140 mm/util.c:128
 __devinet_sysctl_register+0xe4/0x770 net/ipv4/devinet.c:2559
 devinet_sysctl_register+0x344/0x410 net/ipv4/devinet.c:2611
 inetdev_init+0x586/0xb80 net/ipv4/devinet.c:276
 inetdev_event+0xd28/0x20e0 net/ipv4/devinet.c:1530
 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
 register_netdev+0xbe/0x100 net/core/dev.c:10331
 loopback_net_init+0x115/0x380 drivers/net/loopback.c:216
 ops_init+0x595/0x7e0 net/core/net_namespace.c:140
 setup_net+0x3ea/0x1560 net/core/net_namespace.c:333
 copy_net_ns+0x84c/0xc80 net/core/net_namespace.c:474
 create_new_namespaces+0x8c0/0x1270 kernel/nsproxy.c:110
 copy_namespaces+0x3cf/0x4f0 kernel/nsproxy.c:178
 copy_process+0x40b3/0x9b80 kernel/fork.c:2118
 kernel_clone+0x4ea/0x1350 kernel/fork.c:2502
 __do_sys_clone kernel/fork.c:2619 [inline]
 __se_sys_clone+0x225/0x350 kernel/fork.c:2603
 __x64_sys_clone+0x62/0x80 kernel/fork.c:2603
 do_syscall_64+0x9f/0x140 arch/x86/entry/common.c:48
 entry_SYSCALL_64_after_hwframe+0x44/0xae
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