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BUG: KCSAN: data-race in __release_sock / __sk_receive_skb

read to 0xffff8880a0e328ec of 4 bytes by interrupt on cpu 0:
 sk_rcvqueues_full include/net/sock.h:918 [inline]
 __sk_receive_skb+0xf3/0x510 net/core/sock.c:508
 dccp_v6_rcv+0x862/0xc60 net/dccp/ipv6.c:775
 ip6_protocol_deliver_rcu+0x22a/0xbe0 net/ipv6/ip6_input.c:409
 ip6_input_finish+0x30/0x50 net/ipv6/ip6_input.c:450
 NF_HOOK include/linux/netfilter.h:305 [inline]
 NF_HOOK include/linux/netfilter.h:299 [inline]
 ip6_input+0x177/0x190 net/ipv6/ip6_input.c:459
 dst_input include/net/dst.h:442 [inline]
 ip6_rcv_finish+0x110/0x140 net/ipv6/ip6_input.c:76
 NF_HOOK include/linux/netfilter.h:305 [inline]
 NF_HOOK include/linux/netfilter.h:299 [inline]
 ipv6_rcv+0x1a1/0x1b0 net/ipv6/ip6_input.c:284
 __netif_receive_skb_one_core+0xa7/0xe0 net/core/dev.c:4929
 __netif_receive_skb+0x37/0xf0 net/core/dev.c:5043
 process_backlog+0x207/0x4b0 net/core/dev.c:5874
 napi_poll net/core/dev.c:6311 [inline]
 net_rx_action+0x3ae/0xa90 net/core/dev.c:6379
 __do_softirq+0x115/0x33f kernel/softirq.c:292
 do_softirq_own_stack+0x2a/0x40 arch/x86/entry/entry_64.S:1082
 do_softirq.part.0+0x6b/0x80 kernel/softirq.c:337
 do_softirq kernel/softirq.c:329 [inline]
 __local_bh_enable_ip+0x76/0x80 kernel/softirq.c:189
 local_bh_enable include/linux/bottom_half.h:32 [inline]
 rcu_read_unlock_bh include/linux/rcupdate.h:688 [inline]
 ip6_finish_output2+0x7bb/0xec0 net/ipv6/ip6_output.c:117
 __ip6_finish_output net/ipv6/ip6_output.c:142 [inline]
 __ip6_finish_output+0x2d7/0x330 net/ipv6/ip6_output.c:127
 ip6_finish_output+0x41/0x160 net/ipv6/ip6_output.c:152
 NF_HOOK_COND include/linux/netfilter.h:294 [inline]
 ip6_output+0xf2/0x280 net/ipv6/ip6_output.c:175
 dst_output include/net/dst.h:436 [inline]
 NF_HOOK include/linux/netfilter.h:305 [inline]
 NF_HOOK include/linux/netfilter.h:299 [inline]
 ip6_xmit+0x6cb/0xcd0 net/ipv6/ip6_output.c:279
 inet6_csk_xmit+0x170/0x1f0 net/ipv6/inet6_connection_sock.c:135
 dccp_transmit_skb+0x5a2/0x940 net/dccp/output.c:138
 dccp_send_ack+0x136/0x1e0 net/dccp/output.c:591
 ccid2_hc_rx_packet_recv+0xdd/0xf0 net/dccp/ccids/ccid2.c:766
 ccid_hc_rx_packet_recv net/dccp/ccid.h:182 [inline]
 dccp_deliver_input_to_ccids+0x92/0x140 net/dccp/input.c:176
 dccp_rcv_established net/dccp/input.c:374 [inline]
 dccp_rcv_established+0x91/0xc0 net/dccp/input.c:364
 dccp_v6_do_rcv+0x563/0x5f0 net/dccp/ipv6.c:606
 sk_backlog_rcv include/net/sock.h:950 [inline]
 __release_sock+0x135/0x1e0 net/core/sock.c:2439
 release_sock+0x61/0x160 net/core/sock.c:2955
 dccp_sendmsg+0x41b/0x780 net/dccp/proto.c:814
 inet_sendmsg+0x6d/0x90 net/ipv4/af_inet.c:807
 sock_sendmsg_nosec net/socket.c:637 [inline]
 sock_sendmsg+0x9f/0xc0 net/socket.c:657
 ___sys_sendmsg+0x2b7/0x5d0 net/socket.c:2311
 __sys_sendmmsg+0x123/0x350 net/socket.c:2413
 __do_sys_sendmmsg net/socket.c:2442 [inline]
 __se_sys_sendmmsg net/socket.c:2439 [inline]
 __x64_sys_sendmmsg+0x64/0x80 net/socket.c:2439
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffff8880a0e328ec of 4 bytes by task 22743 on cpu 1:
 __release_sock+0x17b/0x1e0 net/core/sock.c:2453
 release_sock+0x61/0x160 net/core/sock.c:2955
 dccp_sendmsg+0x41b/0x780 net/dccp/proto.c:814
 inet_sendmsg+0x6d/0x90 net/ipv4/af_inet.c:807
 sock_sendmsg_nosec net/socket.c:637 [inline]
 sock_sendmsg+0x9f/0xc0 net/socket.c:657
 ___sys_sendmsg+0x2b7/0x5d0 net/socket.c:2311
 __sys_sendmmsg+0x123/0x350 net/socket.c:2413
 __do_sys_sendmmsg net/socket.c:2442 [inline]
 __se_sys_sendmmsg net/socket.c:2439 [inline]
 __x64_sys_sendmmsg+0x64/0x80 net/socket.c:2439
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 22743 Comm: syz-executor.3 Not tainted 5.4.0-rc7+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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