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BUG: KCSAN: data-race in rcu_gp_fqs_loop / rcu_preempt_deferred_qs_irqrestore

write to 0xffffffff85c7d0d0 of 8 bytes by task 8022 on cpu 0:
 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]
 __fib6_clean_all+0x128/0x150 net/ipv6/ip6_fib.c:2173
 fib6_clean_all+0x34/0x50 net/ipv6/ip6_fib.c:2179
 rt6_sync_up+0x9f/0x110 net/ipv6/route.c:4612
 addrconf_notify+0x254/0x1550 net/ipv6/addrconf.c:3604
 notifier_call_chain+0xd7/0x160 kernel/notifier.c:83
 __raw_notifier_call_chain kernel/notifier.c:361 [inline]
 raw_notifier_call_chain+0x37/0x50 kernel/notifier.c:368
 call_netdevice_notifiers_info net/core/dev.c:1893 [inline]
 call_netdevice_notifiers_info+0x9a/0x120 net/core/dev.c:1878
 netdev_state_change net/core/dev.c:1378 [inline]
 netdev_state_change+0xb2/0xd0 net/core/dev.c:1371
 linkwatch_do_dev+0xd8/0xf0 net/core/link_watch.c:159
 __linkwatch_run_queue+0x1a9/0x510 net/core/link_watch.c:204
 linkwatch_event+0x54/0x70 net/core/link_watch.c:243
 process_one_work+0x3d4/0x890 kernel/workqueue.c:2264
 worker_thread+0xa0/0x800 kernel/workqueue.c:2410
 kthread+0x1d4/0x200 drivers/block/aoe/aoecmd.c:1253
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352

read to 0xffffffff85c7d0d0 of 8 bytes by task 10 on cpu 1:
 rcu_gp_fqs_loop+0x23c/0x580 kernel/rcu/tree.c:1667
 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: 1 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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