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BUG: KCSAN: data-race in batadv_hard_if_event / batadv_mcast_mla_update

write to 0xffff8881224d6c10 of 1 bytes by task 2263 on cpu 0:
 batadv_hardif_remove_interface net/batman-adv/hard-interface.c:928 [inline]
 batadv_hard_if_event+0x76a/0x1070 net/batman-adv/hard-interface.c:986
 notifier_call_chain kernel/notifier.c:85 [inline]
 raw_notifier_call_chain+0x6f/0x1b0 kernel/notifier.c:453
 call_netdevice_notifiers_info+0xae/0x100 net/core/dev.c:2176
 call_netdevice_notifiers_extack net/core/dev.c:2214 [inline]
 call_netdevice_notifiers net/core/dev.c:2228 [inline]
 unregister_netdevice_many_notify+0xd9a/0x16a0 net/core/dev.c:11972
 unregister_netdevice_many net/core/dev.c:12036 [inline]
 unregister_netdevice_queue+0x1f5/0x220 net/core/dev.c:11879
 unregister_netdevice include/linux/netdevice.h:3374 [inline]
 nsim_destroy+0xf4/0x360 drivers/net/netdevsim/netdev.c:1064
 __nsim_dev_port_del+0xcf/0x110 drivers/net/netdevsim/dev.c:1428
 nsim_dev_port_del_all drivers/net/netdevsim/dev.c:1440 [inline]
 nsim_dev_reload_destroy+0x1a3/0x2c0 drivers/net/netdevsim/dev.c:1661
 nsim_dev_reload_down+0x67/0x80 drivers/net/netdevsim/dev.c:968
 devlink_reload+0xad/0x580 net/devlink/dev.c:461
 devlink_nl_reload_doit+0x772/0x8f0 net/devlink/dev.c:584
 genl_family_rcv_msg_doit+0x140/0x1b0 net/netlink/genetlink.c:1115
 genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]
 genl_rcv_msg+0x422/0x460 net/netlink/genetlink.c:1210
 netlink_rcv_skb+0x123/0x220 net/netlink/af_netlink.c:2534
 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219
 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
 netlink_unicast+0x5a1/0x670 net/netlink/af_netlink.c:1339
 netlink_sendmsg+0x58b/0x6b0 net/netlink/af_netlink.c:1883
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg+0x145/0x180 net/socket.c:727
 ____sys_sendmsg+0x31e/0x4e0 net/socket.c:2566
 ___sys_sendmsg+0x17b/0x1d0 net/socket.c:2620
 __sys_sendmsg net/socket.c:2652 [inline]
 __do_sys_sendmsg net/socket.c:2657 [inline]
 __se_sys_sendmsg net/socket.c:2655 [inline]
 __x64_sys_sendmsg+0xd4/0x160 net/socket.c:2655
 x64_sys_call+0x2999/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:47
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd0/0x1a0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881224d6c10 of 1 bytes by task 15923 on cpu 1:
 batadv_mcast_mla_forw_flags_get net/batman-adv/multicast.c:252 [inline]
 batadv_mcast_mla_flags_get net/batman-adv/multicast.c:289 [inline]
 __batadv_mcast_mla_update net/batman-adv/multicast.c:909 [inline]
 batadv_mcast_mla_update+0x29f/0x1850 net/batman-adv/multicast.c:948
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0x4cb/0x9d0 kernel/workqueue.c:3319
 worker_thread+0x582/0x770 kernel/workqueue.c:3400
 kthread+0x486/0x510 kernel/kthread.c:464
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

value changed: 0x00 -> 0x01

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 15923 Comm: kworker/u8:0 Not tainted 6.15.0-rc7-syzkaller-00099-g94305e83eccb #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: bat_events batadv_mcast_mla_update
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