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BUG: KCSAN: data-race in __rcu_read_unlock / rcu_report_exp_cpu_mult

write to 0xffffffff85a7d180 of 8 bytes by task 14866 on cpu 1:
 rcu_report_exp_cpu_mult+0x4f/0xa0 kernel/rcu/tree_exp.h:244
 sync_rcu_exp_select_node_cpus+0x478/0x510 kernel/rcu/tree_exp.h:414
 sync_rcu_exp_select_cpus+0x30c/0x590 kernel/rcu/tree_exp.h:439
 rcu_exp_sel_wait_wake kernel/rcu/tree_exp.h:575 [inline]
 wait_rcu_exp_gp+0x25/0x40 kernel/rcu/tree_exp.h:589
 process_one_work+0x3d4/0x890 kernel/workqueue.c:2269
 worker_thread+0xa0/0x800 kernel/workqueue.c:2415
 kthread+0x1d4/0x200 drivers/block/aoe/aoecmd.c:1253
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352

read to 0xffffffff85a7d180 of 8 bytes by task 7551 on cpu 0:
 rcu_read_unlock_special kernel/rcu/tree_plugin.h:615 [inline]
 __rcu_read_unlock+0x381/0x3c0 kernel/rcu/tree_plugin.h:383
 rcu_read_unlock include/linux/rcupdate.h:652 [inline]
 __ip_queue_xmit+0x3b0/0xa40 net/ipv4/ip_output.c:533
 ip_queue_xmit+0x45/0x60 include/net/ip.h:237
 __tcp_transmit_skb+0xe81/0x1d60 net/ipv4/tcp_output.c:1169
 tcp_transmit_skb net/ipv4/tcp_output.c:1185 [inline]
 tcp_write_xmit+0xa54/0x3120 net/ipv4/tcp_output.c:2440
 tcp_tsq_write.part.0+0xec/0x160 net/ipv4/tcp_output.c:799
 tcp_tsq_write include/net/sock.h:658 [inline]
 tcp_release_cb+0x1bc/0x200 net/ipv4/tcp_output.c:869
 release_sock+0x96/0x160 net/core/sock.c:2961
 tcp_sendmsg+0x44/0x60 net/ipv4/tcp.c:1437
 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
 sock_write_iter+0x16b/0x210 net/socket.c:989
 call_write_iter include/linux/fs.h:1895 [inline]
 new_sync_write+0x388/0x4a0 fs/read_write.c:483
 __vfs_write+0xb1/0xc0 fs/read_write.c:496
 vfs_write fs/read_write.c:558 [inline]
 vfs_write+0x18a/0x390 fs/read_write.c:542
 ksys_write+0xd5/0x1b0 fs/read_write.c:611
 __do_sys_write fs/read_write.c:623 [inline]
 __se_sys_write fs/read_write.c:620 [inline]
 __x64_sys_write+0x4c/0x60 fs/read_write.c:620
 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: 0 PID: 7551 Comm: syz-fuzzer Not tainted 5.4.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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