syzbot

bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:1c, vlan:0)
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BUG: KCSAN: data-race in br_fdb_update / br_fdb_update

write to 0xffff8880985a9008 of 8 bytes by interrupt on cpu 1:
 br_fdb_update+0x319/0x590 net/bridge/br_fdb.c:603
 br_handle_frame_finish+0x16d/0xa10 net/bridge/br_input.c:95
 br_nf_hook_thresh+0x184/0x1c0 net/bridge/br_netfilter_hooks.c:1021
 br_nf_pre_routing_finish_ipv6+0x4ab/0x4c0 net/bridge/br_netfilter_ipv6.c:187
 NF_HOOK include/linux/netfilter.h:301 [inline]
 br_nf_pre_routing_ipv6+0x1ed/0x280 net/bridge/br_netfilter_ipv6.c:236
 br_nf_pre_routing+0x4d6/0xb40 net/bridge/br_netfilter_hooks.c:505
 nf_hook_entry_hookfn include/linux/netfilter.h:136 [inline]
 nf_hook_bridge_pre net/bridge/br_input.c:228 [inline]
 br_handle_frame+0x413/0xb10 net/bridge/br_input.c:356
 __netif_receive_skb_core+0xea9/0x1da0 net/core/dev.c:5180
 __netif_receive_skb_one_core net/core/dev.c:5284 [inline]
 __netif_receive_skb+0x52/0x1b0 net/core/dev.c:5400
 process_backlog+0x29f/0x4a0 net/core/dev.c:6242
 napi_poll+0x178/0x4f0 net/core/dev.c:6688
 net_rx_action+0x1ba/0x530 net/core/dev.c:6758
 __do_softirq+0x198/0x360 kernel/softirq.c:298
 run_ksoftirqd+0x2f/0x60 kernel/softirq.c:652
 smpboot_thread_fn+0x347/0x530 kernel/smpboot.c:165
 kthread+0x20d/0x230 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

read to 0xffff8880985a9008 of 8 bytes by interrupt on cpu 0:
 br_fdb_update+0x1a4/0x590 net/bridge/br_fdb.c:601
 br_handle_frame_finish+0x16d/0xa10 net/bridge/br_input.c:95
 br_nf_hook_thresh+0x184/0x1c0 net/bridge/br_netfilter_hooks.c:1021
 br_nf_pre_routing_finish_ipv6+0x4ab/0x4c0 net/bridge/br_netfilter_ipv6.c:187
 NF_HOOK include/linux/netfilter.h:301 [inline]
 br_nf_pre_routing_ipv6+0x1ed/0x280 net/bridge/br_netfilter_ipv6.c:236
 br_nf_pre_routing+0x4d6/0xb40 net/bridge/br_netfilter_hooks.c:505
 nf_hook_entry_hookfn include/linux/netfilter.h:136 [inline]
 nf_hook_bridge_pre net/bridge/br_input.c:228 [inline]
 br_handle_frame+0x413/0xb10 net/bridge/br_input.c:356
 __netif_receive_skb_core+0xea9/0x1da0 net/core/dev.c:5180
 __netif_receive_skb_one_core net/core/dev.c:5284 [inline]
 __netif_receive_skb+0x52/0x1b0 net/core/dev.c:5400
 process_backlog+0x29f/0x4a0 net/core/dev.c:6242
 napi_poll+0x178/0x4f0 net/core/dev.c:6688
 net_rx_action+0x1ba/0x530 net/core/dev.c:6758
 __do_softirq+0x198/0x360 kernel/softirq.c:298
 run_ksoftirqd+0x2f/0x60 kernel/softirq.c:652
 smpboot_thread_fn+0x347/0x530 kernel/smpboot.c:165
 kthread+0x20d/0x230 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 9 Comm: ksoftirqd/0 Not tainted 5.9.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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