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BUG: KCSAN: data-race in __wb_writeout_add / writeout_period

write to 0xffffffff87125d70 of 8 bytes by interrupt on cpu 0:
 writeout_period+0xa6/0xe0 mm/page-writeback.c:614
 call_timer_fn+0x37/0x2f0 kernel/time/timer.c:1700
 expire_timers kernel/time/timer.c:1751 [inline]
 __run_timers+0x448/0x630 kernel/time/timer.c:2038
 run_timer_softirq+0x31/0x40 kernel/time/timer.c:2053
 __do_softirq+0xc4/0x27b kernel/softirq.c:553
 invoke_softirq kernel/softirq.c:427 [inline]
 __irq_exit_rcu kernel/softirq.c:632 [inline]
 irq_exit_rcu+0x3b/0x90 kernel/softirq.c:644
 sysvec_apic_timer_interrupt+0x6f/0x80 arch/x86/kernel/apic/apic.c:1076
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:649
 is_atomic kernel/kcsan/core.c:249 [inline]
 should_watch kernel/kcsan/core.c:277 [inline]
 check_access kernel/kcsan/core.c:752 [inline]
 __tsan_read8+0xe4/0x180 kernel/kcsan/core.c:1025
 pv_queued_spin_unlock arch/x86/include/asm/paravirt.h:589 [inline]
 queued_spin_unlock arch/x86/include/asm/qspinlock.h:57 [inline]
 do_raw_spin_unlock include/linux/spinlock.h:204 [inline]
 __raw_spin_unlock include/linux/spinlock_api_smp.h:142 [inline]
 _raw_spin_unlock+0x14/0x40 kernel/locking/spinlock.c:186
 spin_unlock include/linux/spinlock.h:391 [inline]
 kernfs_put+0x19d/0x2a0 fs/kernfs/dir.c:568
 kernfs_remove_by_name_ns+0x91/0xe0 fs/kernfs/dir.c:1686
 kernfs_remove_by_name include/linux/kernfs.h:623 [inline]
 remove_files fs/sysfs/group.c:28 [inline]
 sysfs_remove_group+0x95/0x190 fs/sysfs/group.c:292
 sysfs_remove_groups+0x3a/0x80 fs/sysfs/group.c:316
 device_remove_groups drivers/base/core.c:2748 [inline]
 device_remove_attrs+0x10d/0x190 drivers/base/core.c:2923
 device_del+0x35b/0x7a0 drivers/base/core.c:3827
 netdev_unregister_kobject+0x10c/0x120 net/core/net-sysfs.c:2027
 unregister_netdevice_many_notify+0xb17/0xf00 net/core/dev.c:11113
 unregister_netdevice_many+0x19/0x20 net/core/dev.c:11139
 ip_tunnel_delete_nets+0x20b/0x240 net/ipv4/ip_tunnel.c:1144
 ipgre_exit_batch_net+0x2e/0x30 net/ipv4/ip_gre.c:1030
 ops_exit_list net/core/net_namespace.c:175 [inline]
 cleanup_net+0x419/0x770 net/core/net_namespace.c:618
 process_one_work kernel/workqueue.c:2633 [inline]
 process_scheduled_works+0x5b8/0xa40 kernel/workqueue.c:2706
 worker_thread+0x525/0x730 kernel/workqueue.c:2787
 kthread+0x1d7/0x210 kernel/kthread.c:388
 ret_from_fork+0x48/0x60 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242

read to 0xffffffff87125d70 of 8 bytes by task 5372 on cpu 1:
 wb_domain_writeout_add mm/page-writeback.c:563 [inline]
 __wb_writeout_add+0x8a/0x1d0 mm/page-writeback.c:584
 __folio_end_writeback+0x21b/0x4a0 mm/page-writeback.c:2963
 folio_end_writeback+0x74/0x1f0 mm/filemap.c:1599
 ext4_finish_bio+0x47b/0x8e0 fs/ext4/page-io.c:145
 ext4_release_io_end+0x8c/0x1e0 fs/ext4/page-io.c:160
 ext4_end_io_end fs/ext4/page-io.c:194 [inline]
 ext4_do_flush_completed_IO fs/ext4/page-io.c:259 [inline]
 ext4_end_io_rsv_work+0x2d3/0x360 fs/ext4/page-io.c:273
 process_one_work kernel/workqueue.c:2633 [inline]
 process_scheduled_works+0x5b8/0xa40 kernel/workqueue.c:2706
 worker_thread+0x525/0x730 kernel/workqueue.c:2787
 kthread+0x1d7/0x210 kernel/kthread.c:388
 ret_from_fork+0x48/0x60 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242

value changed: 0x00000001000052ae -> 0x00000001000053da

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 5372 Comm: kworker/u4:10 Not tainted 6.8.0-rc5-syzkaller-00029-g39133352cbed #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
Workqueue: ext4-rsv-conversion ext4_end_io_rsv_work
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