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BUG: KCSAN: data-race in _prb_read_valid / prb_reserve

write to 0xffffffff866a1da0 of 8 bytes by task 20166 on cpu 0:
 prb_reserve+0x740/0xb60
 vprintk_store+0x558/0x870 kernel/printk/printk.c:2326
 vprintk_emit+0x15e/0x680 kernel/printk/printk.c:2408
 dev_vprintk_emit+0x1df/0x210 drivers/base/core.c:4935
 dev_printk_emit+0x82/0xb0 drivers/base/core.c:4946
 __netdev_printk+0x352/0x3e0 net/core/dev.c:11938
 netdev_info+0x99/0xc0 net/core/dev.c:11993
 nsim_udp_tunnel_set_port+0x175/0x190 drivers/net/netdevsim/udp_tunnels.c:34
 udp_tunnel_nic_device_sync_by_port net/ipv4/udp_tunnel_nic.c:246 [inline]
 __udp_tunnel_nic_device_sync+0x57b/0x9e0 net/ipv4/udp_tunnel_nic.c:289
 udp_tunnel_nic_device_sync net/ipv4/udp_tunnel_nic.c:312 [inline]
 __udp_tunnel_nic_add_port+0x66d/0x6e0 net/ipv4/udp_tunnel_nic.c:531
 udp_tunnel_nic_add_port include/net/udp_tunnel.h:350 [inline]
 udp_tunnel_push_rx_port+0xea/0x120 net/ipv4/udp_tunnel_core.c:96
 geneve_offload_rx_ports drivers/net/geneve.c:1176 [inline]
 geneve_netdevice_event+0x169/0x1c0 drivers/net/geneve.c:1881
 notifier_call_chain kernel/notifier.c:85 [inline]
 raw_notifier_call_chain+0x6f/0x1d0 kernel/notifier.c:453
 call_netdevice_notifiers_info+0xae/0x100 net/core/dev.c:1996
 call_netdevice_notifiers_extack net/core/dev.c:2034 [inline]
 call_netdevice_notifiers+0x49/0x70 net/core/dev.c:2048
 udp_tunnel_get_rx_info include/net/udp_tunnel.h:138 [inline]
 udp_tunnel_nic_register net/ipv4/udp_tunnel_nic.c:825 [inline]
 udp_tunnel_nic_netdevice_event+0xa49/0xc80 net/ipv4/udp_tunnel_nic.c:893
 notifier_call_chain kernel/notifier.c:85 [inline]
 raw_notifier_call_chain+0x6f/0x1d0 kernel/notifier.c:453
 call_netdevice_notifiers_info+0xae/0x100 net/core/dev.c:1996
 call_netdevice_notifiers_extack net/core/dev.c:2034 [inline]
 call_netdevice_notifiers net/core/dev.c:2048 [inline]
 register_netdevice+0xca9/0xe30 net/core/dev.c:10632
 nsim_init_netdevsim drivers/net/netdevsim/netdev.c:733 [inline]
 nsim_create+0x473/0x590 drivers/net/netdevsim/netdev.c:793
 __nsim_dev_port_add+0x425/0x590 drivers/net/netdevsim/dev.c:1393
 nsim_dev_port_add_all drivers/net/netdevsim/dev.c:1449 [inline]
 nsim_dev_reload_create drivers/net/netdevsim/dev.c:1501 [inline]
 nsim_dev_reload_up+0x434/0x510 drivers/net/netdevsim/dev.c:988
 devlink_reload+0x31a/0x5a0 net/devlink/dev.c:474
 devlink_nl_reload_doit+0x78c/0x8f0 net/devlink/dev.c:584
 genl_family_rcv_msg_doit net/netlink/genetlink.c:1115 [inline]
 genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]
 genl_rcv_msg+0x61b/0x6c0 net/netlink/genetlink.c:1210
 netlink_rcv_skb+0x12c/0x230 net/netlink/af_netlink.c:2542
 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219
 netlink_unicast_kernel net/netlink/af_netlink.c:1321 [inline]
 netlink_unicast+0x599/0x670 net/netlink/af_netlink.c:1347
 netlink_sendmsg+0x5cc/0x6e0 net/netlink/af_netlink.c:1891
 sock_sendmsg_nosec net/socket.c:711 [inline]
 __sock_sendmsg+0x140/0x180 net/socket.c:726
 ____sys_sendmsg+0x312/0x410 net/socket.c:2583
 ___sys_sendmsg net/socket.c:2637 [inline]
 __sys_sendmsg+0x19d/0x230 net/socket.c:2669
 __do_sys_sendmsg net/socket.c:2674 [inline]
 __se_sys_sendmsg net/socket.c:2672 [inline]
 __x64_sys_sendmsg+0x46/0x50 net/socket.c:2672
 x64_sys_call+0x2734/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:47
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff866a1da0 of 8 bytes by task 2990 on cpu 1:
 desc_read kernel/printk/printk_ringbuffer.c:486 [inline]
 prb_first_seq kernel/printk/printk_ringbuffer.c:1957 [inline]
 _prb_read_valid+0x3bb/0xba0 kernel/printk/printk_ringbuffer.c:2114
 prb_read_valid+0x3d/0x60 kernel/printk/printk_ringbuffer.c:2182
 syslog_print+0xfc/0x760 kernel/printk/printk.c:1633
 do_syslog+0x3a1/0x7f0 kernel/printk/printk.c:1785
 __do_sys_syslog kernel/printk/printk.c:1877 [inline]
 __se_sys_syslog kernel/printk/printk.c:1875 [inline]
 __x64_sys_syslog+0x43/0x50 kernel/printk/printk.c:1875
 x64_sys_call+0x29be/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:104
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000000000284 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 2990 Comm: klogd Not tainted 6.13.0-rc4-syzkaller-00004-gf07044dd0df0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
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