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BUG: KCSAN: data-race in rcu_gp_fqs_check_wake / rcu_note_context_switch

write to 0xffffffff85a7d490 of 8 bytes by task 13452 on cpu 0:
 rcu_preempt_ctxt_queue kernel/rcu/tree_plugin.h:223 [inline]
 rcu_note_context_switch+0x6f6/0x760 kernel/rcu/tree_plugin.h:315
 __schedule+0xa4/0x640 kernel/sched/core.c:4007
 preempt_schedule_irq+0x57/0x90 kernel/sched/core.c:4319
 restore_regs_and_return_to_kernel+0x0/0x25
 should_watch kernel/kcsan/core.c:167 [inline]
 __kcsan_setup_watchpoint+0xa3/0x4a0 kernel/kcsan/core.c:307
 __tsan_read4 kernel/kcsan/kcsan.c:35 [inline]
 __tsan_read4+0x2c/0x30 kernel/kcsan/kcsan.c:35
 __rcu_read_unlock+0x41/0x3c0 kernel/rcu/tree_plugin.h:376
 rcu_read_unlock include/linux/rcupdate.h:652 [inline]
 inet_twsk_purge+0x259/0x2d0 net/ipv4/inet_timewait_sock.c:299
 dccp_v4_exit_batch+0x23/0x30 net/dccp/ipv4.c:1030
 ops_exit_list.isra.0+0xa2/0xc0 net/core/net_namespace.c:175
 setup_net+0x31c/0x4b0 net/core/net_namespace.c:357
 copy_net_ns+0x1dc/0x340 net/core/net_namespace.c:475
 create_new_namespaces+0x2e2/0x4b0 kernel/nsproxy.c:103
 unshare_nsproxy_namespaces+0xb9/0x170 kernel/nsproxy.c:202

read to 0xffffffff85a7d490 of 8 bytes by task 10 on cpu 1:
 rcu_gp_fqs_check_wake kernel/rcu/tree.c:1584 [inline]
 rcu_gp_fqs_check_wake+0x93/0xd0 kernel/rcu/tree.c:1574
 rcu_gp_fqs_loop+0x1df/0x580 kernel/rcu/tree.c:1639
 rcu_gp_kthread+0x143/0x230 kernel/rcu/tree.c:1799
 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: 1 PID: 10 Comm: rcu_preempt Not tainted 5.4.0-rc3+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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