syzbot

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BUG: KCSAN: data-race in register_netdevice / type_show

write to 0xffff88813c75e518 of 1 bytes by task 19360 on cpu 1:
 register_netdevice+0xb9f/0xdf0 net/core/dev.c:10050
 lapbeth_new_device drivers/net/wan/lapbether.c:414 [inline]
 lapbeth_device_event+0x4a0/0x6c0 drivers/net/wan/lapbether.c:456
 notifier_call_chain kernel/notifier.c:87 [inline]
 raw_notifier_call_chain+0x53/0xb0 kernel/notifier.c:455
 __dev_notify_flags+0x1d6/0x3a0
 dev_change_flags+0xa2/0xc0 net/core/dev.c:8607
 do_setlink+0x778/0x2230 net/core/rtnetlink.c:2780
 __rtnl_newlink net/core/rtnetlink.c:3546 [inline]
 rtnl_newlink+0x114c/0x16a0 net/core/rtnetlink.c:3593
 rtnetlink_rcv_msg+0x811/0x8c0 net/core/rtnetlink.c:6089
 netlink_rcv_skb+0x13e/0x240 net/netlink/af_netlink.c:2501
 rtnetlink_rcv+0x18/0x20 net/core/rtnetlink.c:6107
 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
 netlink_unicast+0x58a/0x660 net/netlink/af_netlink.c:1345
 netlink_sendmsg+0x661/0x750 net/netlink/af_netlink.c:1921
 sock_sendmsg_nosec net/socket.c:714 [inline]
 sock_sendmsg net/socket.c:734 [inline]
 __sys_sendto+0x21e/0x2c0 net/socket.c:2119
 __do_sys_sendto net/socket.c:2131 [inline]
 __se_sys_sendto net/socket.c:2127 [inline]
 __x64_sys_sendto+0x74/0x90 net/socket.c:2127
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x46/0xb0

read to 0xffff88813c75e518 of 1 bytes by task 17266 on cpu 0:
 dev_isalive net/core/net-sysfs.c:38 [inline]
 netdev_show net/core/net-sysfs.c:50 [inline]
 type_show+0x24/0x90 net/core/net-sysfs.c:112
 dev_attr_show+0x35/0x90 drivers/base/core.c:2095
 sysfs_kf_seq_show+0x175/0x240 fs/sysfs/file.c:59
 kernfs_seq_show+0x75/0x80 fs/kernfs/file.c:162
 seq_read_iter+0x2c3/0x8e0 fs/seq_file.c:230
 kernfs_fop_read_iter+0xd1/0x2f0 fs/kernfs/file.c:235
 call_read_iter include/linux/fs.h:2052 [inline]
 new_sync_read fs/read_write.c:401 [inline]
 vfs_read+0x5a5/0x6a0 fs/read_write.c:482
 ksys_read+0xe8/0x1a0 fs/read_write.c:620
 __do_sys_read fs/read_write.c:630 [inline]
 __se_sys_read fs/read_write.c:628 [inline]
 __x64_sys_read+0x3e/0x50 fs/read_write.c:628
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x46/0xb0

value changed: 0x00 -> 0x01

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 17266 Comm: udevd Tainted: G        W         5.19.0-rc2-syzkaller-00205-g462abc9de7a1-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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