==================================================================
BUG: KCSAN: data-race in batadv_hard_if_event / batadv_mcast_mla_update

write to 0xffff888148597810 of 1 bytes by task 8979 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:2026
 call_netdevice_notifiers_extack net/core/dev.c:2064 [inline]
 call_netdevice_notifiers net/core/dev.c:2078 [inline]
 unregister_netdevice_many_notify+0x8b7/0x11b0 net/core/dev.c:11545
 unregister_netdevice_many net/core/dev.c:11609 [inline]
 unregister_netdevice_queue+0x1f4/0x220 net/core/dev.c:11481
 unregister_netdevice include/linux/netdevice.h:3192 [inline]
 __tun_detach+0x79e/0xaa0 drivers/net/tun.c:685
 tun_detach drivers/net/tun.c:701 [inline]
 tun_chr_close+0x58/0xf0 drivers/net/tun.c:3517
 __fput+0x17a/0x6d0 fs/file_table.c:450
 ____fput+0x1c/0x30 fs/file_table.c:478
 task_work_run+0x13a/0x1a0 kernel/task_work.c:239
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0xa8/0x120 kernel/entry/common.c:218
 do_syscall_64+0xd6/0x1c0 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888148597810 of 1 bytes by task 19577 on cpu 1:
 batadv_mcast_mla_forw_flags_get net/batman-adv/multicast.c:253 [inline]
 batadv_mcast_mla_flags_get net/batman-adv/multicast.c:290 [inline]
 __batadv_mcast_mla_update net/batman-adv/multicast.c:910 [inline]
 batadv_mcast_mla_update+0x21b/0x1700 net/batman-adv/multicast.c:949
 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+0x1d1/0x210 kernel/kthread.c:389
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:147
 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: 19577 Comm: kworker/u8:33 Not tainted 6.13.0-rc7-syzkaller-00189-g595523945be0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Workqueue: bat_events batadv_mcast_mla_update
==================================================================