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BUG: KCSAN: data-race in hsr_forward_skb / hsr_forward_skb

write to 0xffff888100a49120 of 8 bytes by interrupt on cpu 1:
 hsr_forward_skb+0x9d9/0xaf0 net/hsr/hsr_forward.c:547
 hsr_dev_xmit+0x56/0x80 net/hsr/hsr_device.c:220
 __netdev_start_xmit include/linux/netdevice.h:4634 [inline]
 netdev_start_xmit include/linux/netdevice.h:4648 [inline]
 xmit_one+0xc0/0x310 net/core/dev.c:3561
 dev_hard_start_xmit net/core/dev.c:3577 [inline]
 __dev_queue_xmit+0xf00/0x15a0 net/core/dev.c:4136
 dev_queue_xmit+0x13/0x20 net/core/dev.c:4169
 br_dev_queue_push_xmit+0x3bf/0x420 net/bridge/br_forward.c:52
 NF_HOOK include/linux/netfilter.h:301 [inline]
 br_forward_finish net/bridge/br_forward.c:65 [inline]
 NF_HOOK include/linux/netfilter.h:301 [inline]
 __br_forward+0x2d2/0x400 net/bridge/br_forward.c:109
 deliver_clone net/bridge/br_forward.c:125 [inline]
 maybe_deliver net/bridge/br_forward.c:181 [inline]
 br_flood+0x3af/0x5b0 net/bridge/br_forward.c:223
 br_handle_frame_finish+0x96f/0xa10 net/bridge/br_input.c:166
 nf_hook_bridge_pre net/bridge/br_input.c:250 [inline]
 br_handle_frame+0x4d8/0xb10 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 0xffff888100a49120 of 8 bytes by task 22471 on cpu 0:
 hsr_forward_skb+0x9ca/0xaf0 net/hsr/hsr_forward.c:547
 hsr_dev_xmit+0x56/0x80 net/hsr/hsr_device.c:220
 __netdev_start_xmit include/linux/netdevice.h:4634 [inline]
 netdev_start_xmit include/linux/netdevice.h:4648 [inline]
 xmit_one+0xc0/0x310 net/core/dev.c:3561
 dev_hard_start_xmit net/core/dev.c:3577 [inline]
 __dev_queue_xmit+0xf00/0x15a0 net/core/dev.c:4136
 dev_queue_xmit+0x13/0x20 net/core/dev.c:4169
 br_dev_queue_push_xmit+0x3bf/0x420 net/bridge/br_forward.c:52
 NF_HOOK include/linux/netfilter.h:301 [inline]
 br_forward_finish net/bridge/br_forward.c:65 [inline]
 NF_HOOK include/linux/netfilter.h:301 [inline]
 __br_forward+0x2d2/0x400 net/bridge/br_forward.c:109
 deliver_clone net/bridge/br_forward.c:125 [inline]
 maybe_deliver net/bridge/br_forward.c:181 [inline]
 br_flood+0x3af/0x5b0 net/bridge/br_forward.c:223
 br_dev_xmit+0x7dc/0x870 net/bridge/br_device.c:95
 __netdev_start_xmit include/linux/netdevice.h:4634 [inline]
 netdev_start_xmit include/linux/netdevice.h:4648 [inline]
 xmit_one+0xc0/0x310 net/core/dev.c:3561
 dev_hard_start_xmit net/core/dev.c:3577 [inline]
 __dev_queue_xmit+0xf00/0x15a0 net/core/dev.c:4136
 dev_queue_xmit+0x13/0x20 net/core/dev.c:4169
 neigh_hh_output include/net/neighbour.h:498 [inline]
 neigh_output include/net/neighbour.h:507 [inline]
 ip_finish_output2+0x707/0xb60 net/ipv4/ip_output.c:228
 __ip_finish_output+0x395/0x3e0 net/ipv4/ip_output.c:306
 ip_finish_output+0x39/0x160 net/ipv4/ip_output.c:316
 NF_HOOK_COND include/linux/netfilter.h:290 [inline]
 ip_mc_output+0x301/0x4d0 net/ipv4/ip_output.c:415
 dst_output include/net/dst.h:443 [inline]
 ip_local_out net/ipv4/ip_output.c:125 [inline]
 ip_send_skb+0x6e/0xe0 net/ipv4/ip_output.c:1566
 udp_send_skb+0x62d/0x860 net/ipv4/udp.c:948
 udp_sendmsg+0x1298/0x1550 net/ipv4/udp.c:1235
 inet_sendmsg+0x5f/0x80 net/ipv4/af_inet.c:817
 sock_sendmsg_nosec net/socket.c:651 [inline]
 sock_sendmsg net/socket.c:671 [inline]
 ____sys_sendmsg+0x360/0x4d0 net/socket.c:2353
 ___sys_sendmsg net/socket.c:2407 [inline]
 __sys_sendmmsg+0x322/0x4b0 net/socket.c:2497
 __do_sys_sendmmsg net/socket.c:2526 [inline]
 __se_sys_sendmmsg net/socket.c:2523 [inline]
 __x64_sys_sendmmsg+0x53/0x60 net/socket.c:2523
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 22471 Comm: syz-executor.4 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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