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BUG: KCSAN: data-race in br_fdb_update / br_fdb_update

write to 0xffff888115640340 of 8 bytes by interrupt on cpu 0:
 br_fdb_update+0x142/0x480 net/bridge/br_fdb.c:911
 br_handle_frame_finish+0x32e/0xe70 net/bridge/br_input.c:141
 br_nf_hook_thresh+0x1e5/0x220
 br_nf_pre_routing_finish_ipv6+0x575/0x5a0
 NF_HOOK include/linux/netfilter.h:314 [inline]
 br_nf_pre_routing_ipv6+0x1f6/0x2a0 net/bridge/br_netfilter_ipv6.c:184
 br_nf_pre_routing+0x517/0xbc0 net/bridge/br_netfilter_hooks.c:533
 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline]
 nf_hook_bridge_pre net/bridge/br_input.c:277 [inline]
 br_handle_frame+0x4dd/0x9a0 net/bridge/br_input.c:424
 __netif_receive_skb_core+0xb00/0x2310 net/core/dev.c:5560
 __netif_receive_skb_one_core net/core/dev.c:5664 [inline]
 __netif_receive_skb+0x5a/0x280 net/core/dev.c:5779
 process_backlog+0x22e/0x440 net/core/dev.c:6111
 __napi_poll+0x63/0x3c0 net/core/dev.c:6775
 napi_poll net/core/dev.c:6844 [inline]
 net_rx_action+0x3a1/0x7f0 net/core/dev.c:6966
 handle_softirqs+0xbf/0x280 kernel/softirq.c:554
 do_softirq+0x5e/0x90 kernel/softirq.c:455
 __local_bh_enable_ip+0x6e/0x70 kernel/softirq.c:382
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 rcu_read_unlock_bh include/linux/rcupdate.h:919 [inline]
 __dev_queue_xmit+0xb4c/0x2040 net/core/dev.c:4455
 dev_queue_xmit include/linux/netdevice.h:3094 [inline]
 neigh_resolve_output+0x3e3/0x450 net/core/neighbour.c:1565
 neigh_output include/net/neighbour.h:542 [inline]
 ip6_finish_output2+0xa6d/0xd20 net/ipv6/ip6_output.c:141
 ip6_finish_output+0x438/0x540 net/ipv6/ip6_output.c:226
 NF_HOOK_COND include/linux/netfilter.h:303 [inline]
 ip6_output+0xf5/0x230 net/ipv6/ip6_output.c:247
 dst_output include/net/dst.h:450 [inline]
 NF_HOOK include/linux/netfilter.h:314 [inline]
 ndisc_send_skb+0x4a2/0x6b0 net/ipv6/ndisc.c:511
 ndisc_send_ns+0x79/0xe0 net/ipv6/ndisc.c:669
 addrconf_dad_work+0x6f1/0xbd0 net/ipv6/addrconf.c:4284
 process_one_work kernel/workqueue.c:3229 [inline]
 process_scheduled_works+0x483/0x9a0 kernel/workqueue.c:3310
 worker_thread+0x51d/0x6f0 kernel/workqueue.c:3391
 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

read to 0xffff888115640340 of 8 bytes by interrupt on cpu 1:
 br_fdb_update+0x10e/0x480 net/bridge/br_fdb.c:910
 br_handle_frame_finish+0x32e/0xe70 net/bridge/br_input.c:141
 br_nf_hook_thresh+0x1e5/0x220
 br_nf_pre_routing_finish_ipv6+0x575/0x5a0
 NF_HOOK include/linux/netfilter.h:314 [inline]
 br_nf_pre_routing_ipv6+0x1f6/0x2a0 net/bridge/br_netfilter_ipv6.c:184
 br_nf_pre_routing+0x517/0xbc0 net/bridge/br_netfilter_hooks.c:533
 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline]
 nf_hook_bridge_pre net/bridge/br_input.c:277 [inline]
 br_handle_frame+0x4dd/0x9a0 net/bridge/br_input.c:424
 __netif_receive_skb_core+0xb00/0x2310 net/core/dev.c:5560
 __netif_receive_skb_one_core net/core/dev.c:5664 [inline]
 __netif_receive_skb+0x5a/0x280 net/core/dev.c:5779
 process_backlog+0x22e/0x440 net/core/dev.c:6111
 __napi_poll+0x63/0x3c0 net/core/dev.c:6775
 napi_poll net/core/dev.c:6844 [inline]
 net_rx_action+0x3a1/0x7f0 net/core/dev.c:6966
 handle_softirqs+0xbf/0x280 kernel/softirq.c:554
 do_softirq+0x5e/0x90 kernel/softirq.c:455
 __local_bh_enable_ip+0x6e/0x70 kernel/softirq.c:382
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 rcu_read_unlock_bh include/linux/rcupdate.h:919 [inline]
 __dev_queue_xmit+0xb4c/0x2040 net/core/dev.c:4455
 dev_queue_xmit include/linux/netdevice.h:3094 [inline]
 neigh_hh_output include/net/neighbour.h:526 [inline]
 neigh_output include/net/neighbour.h:540 [inline]
 ip6_finish_output2+0xa41/0xd20 net/ipv6/ip6_output.c:141
 ip6_finish_output+0x438/0x540 net/ipv6/ip6_output.c:226
 NF_HOOK_COND include/linux/netfilter.h:303 [inline]
 ip6_output+0xf5/0x230 net/ipv6/ip6_output.c:247
 dst_output include/net/dst.h:450 [inline]
 NF_HOOK include/linux/netfilter.h:314 [inline]
 mld_sendpack+0x421/0x6d0 net/ipv6/mcast.c:1819
 mld_send_cr net/ipv6/mcast.c:2120 [inline]
 mld_ifc_work+0x51a/0x7e0 net/ipv6/mcast.c:2651
 process_one_work kernel/workqueue.c:3229 [inline]
 process_scheduled_works+0x483/0x9a0 kernel/workqueue.c:3310
 worker_thread+0x51d/0x6f0 kernel/workqueue.c:3391
 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: 0x00000000ffff9cce -> 0x00000000ffff9cdc

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3324 Comm: kworker/1:2 Not tainted 6.12.0-rc3-syzkaller-00319-gb04ae0f45168 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Workqueue: mld mld_ifc_work
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