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BUG: KCSAN: data-race in batadv_hard_if_event / batadv_mcast_mla_update

write to 0xffff888149974410 of 1 bytes by task 1571 on cpu 0:
 batadv_hardif_remove_interface net/batman-adv/hard-interface.c:930 [inline]
 batadv_hard_if_event+0x896/0xfb0 net/batman-adv/hard-interface.c:988
 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:2141
 call_netdevice_notifiers_extack net/core/dev.c:2179 [inline]
 call_netdevice_notifiers net/core/dev.c:2193 [inline]
 unregister_netdevice_many_notify+0x98a/0x1280 net/core/dev.c:11802
 unregister_netdevice_many net/core/dev.c:11866 [inline]
 unregister_netdevice_queue+0x1f4/0x220 net/core/dev.c:11736
 unregister_netdevice include/linux/netdevice.h:3329 [inline]
 nsim_destroy+0xbd/0x330 drivers/net/netdevsim/netdev.c:1021
 __nsim_dev_port_del+0xcd/0x100 drivers/net/netdevsim/dev.c:1428
 nsim_dev_port_del_all drivers/net/netdevsim/dev.c:1440 [inline]
 nsim_dev_reload_destroy+0x1a6/0x2d0 drivers/net/netdevsim/dev.c:1661
 nsim_drv_remove+0x3e/0x100 drivers/net/netdevsim/dev.c:1676
 nsim_bus_remove+0x15/0x20 drivers/net/netdevsim/bus.c:398
 device_remove drivers/base/dd.c:567 [inline]
 __device_release_driver drivers/base/dd.c:1273 [inline]
 device_release_driver_internal+0x2e5/0x4f0 drivers/base/dd.c:1296
 device_release_driver+0x19/0x20 drivers/base/dd.c:1319
 bus_remove_device+0x26f/0x290 drivers/base/bus.c:579
 device_del+0x370/0x780 drivers/base/core.c:3854
 device_unregister+0x15/0x40 drivers/base/core.c:3895
 nsim_bus_dev_del drivers/net/netdevsim/bus.c:462 [inline]
 del_device_store+0x1cb/0x230 drivers/net/netdevsim/bus.c:226
 bus_attr_store+0x54/0x70 drivers/base/bus.c:172
 sysfs_kf_write+0xae/0xd0 fs/sysfs/file.c:139
 kernfs_fop_write_iter+0x1c8/0x2c0 fs/kernfs/file.c:334
 new_sync_write fs/read_write.c:586 [inline]
 vfs_write+0x77b/0x920 fs/read_write.c:679
 ksys_write+0xe8/0x1b0 fs/read_write.c:731
 __do_sys_write fs/read_write.c:742 [inline]
 __se_sys_write fs/read_write.c:739 [inline]
 __x64_sys_write+0x42/0x50 fs/read_write.c:739
 x64_sys_call+0x287e/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:2
 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 0xffff888149974410 of 1 bytes by task 38 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+0x21b/0x1700 net/batman-adv/multicast.c:948
 process_one_work kernel/workqueue.c:3236 [inline]
 process_scheduled_works+0x483/0x9a0 kernel/workqueue.c:3317
 worker_thread+0x51d/0x6f0 kernel/workqueue.c:3398
 kthread+0x4ae/0x520 kernel/kthread.c:464
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

value changed: 0x00 -> 0x01

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 38 Comm: kworker/u8:2 Not tainted 6.14.0-rc2-syzkaller-00034-gfebbc555cf0f #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Workqueue: bat_events batadv_mcast_mla_update
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