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BUG: KCSAN: data-race in rcu_gp_fqs_check_wake / rcu_preempt_deferred_qs_irqrestore

write to 0xffffffff85c7d0d0 of 8 bytes by task 17748 on cpu 1:
 rcu_preempt_deferred_qs_irqrestore+0x43d/0x580 kernel/rcu/tree_plugin.h:496
 rcu_read_unlock_special kernel/rcu/tree_plugin.h:644 [inline]
 __rcu_read_unlock+0x16a/0x3d0 kernel/rcu/tree_plugin.h:383
 rcu_read_unlock include/linux/rcupdate.h:670 [inline]
 inet_twsk_purge+0x2db/0x390 net/ipv4/inet_timewait_sock.c:299
 dccp_v6_exit_batch+0x23/0x30 net/dccp/ipv6.c:1114
 ops_exit_list.isra.0+0xa2/0xc0 net/core/net_namespace.c:175
 setup_net+0x319/0x4b0 net/core/net_namespace.c:358
 copy_net_ns+0x1e7/0x400 net/core/net_namespace.c:476
 create_new_namespaces+0x2e2/0x550 kernel/nsproxy.c:103
 unshare_nsproxy_namespaces+0xb9/0x170 kernel/nsproxy.c:202
 ksys_unshare+0x2dc/0x710 kernel/fork.c:2935
 __do_sys_unshare kernel/fork.c:3003 [inline]
 __se_sys_unshare kernel/fork.c:3001 [inline]
 __x64_sys_unshare+0x28/0x40 kernel/fork.c:3001
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffffffff85c7d0d0 of 8 bytes by task 10 on cpu 0:
 rcu_gp_fqs_check_wake kernel/rcu/tree.c:1606 [inline]
 rcu_gp_fqs_check_wake+0x93/0xd0 kernel/rcu/tree.c:1596
 rcu_gp_fqs_loop+0x39d/0x580 kernel/rcu/tree.c:1661
 rcu_gp_kthread+0x143/0x230 kernel/rcu/tree.c:1821
 kthread+0x1d4/0x200 drivers/block/aoe/aoecmd.c:1253
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 10 Comm: rcu_preempt Not tainted 5.5.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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