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BUG: KCSAN: data-race in __wb_writeout_add / writeout_period

write to 0xffffffff88408f28 of 8 bytes by interrupt on cpu 0:
 writeout_period+0xa6/0xe0 mm/page-writeback.c:614
 call_timer_fn+0x3a/0x300 kernel/time/timer.c:1793
 expire_timers kernel/time/timer.c:1844 [inline]
 __run_timers kernel/time/timer.c:2418 [inline]
 __run_timer_base+0x417/0x640 kernel/time/timer.c:2429
 run_timer_base kernel/time/timer.c:2438 [inline]
 run_timer_softirq+0x45/0x70 kernel/time/timer.c:2449
 handle_softirqs+0xc8/0x290 kernel/softirq.c:554
 __do_softirq kernel/softirq.c:588 [inline]
 invoke_softirq kernel/softirq.c:428 [inline]
 __irq_exit_rcu kernel/softirq.c:637 [inline]
 irq_exit_rcu+0x3e/0x90 kernel/softirq.c:649
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
 sysvec_apic_timer_interrupt+0x73/0x80 arch/x86/kernel/apic/apic.c:1043
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
 __preempt_count_dec_and_test arch/x86/include/asm/preempt.h:94 [inline]
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
 _raw_spin_unlock_irqrestore+0x3d/0x60 kernel/locking/spinlock.c:194
 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
 __folio_start_writeback+0x327/0x450 mm/page-writeback.c:3082
 ext4_bio_write_folio+0x592/0x9a0 fs/ext4/page-io.c:557
 mpage_submit_folio fs/ext4/inode.c:1869 [inline]
 mpage_map_and_submit_buffers fs/ext4/inode.c:2115 [inline]
 mpage_map_and_submit_extent fs/ext4/inode.c:2254 [inline]
 ext4_do_writepages+0x13a7/0x2110 fs/ext4/inode.c:2679
 ext4_writepages+0x159/0x2e0 fs/ext4/inode.c:2768
 do_writepages+0x1d8/0x480 mm/page-writeback.c:2613
 filemap_fdatawrite_wbc+0xdb/0x100 mm/filemap.c:397
 __filemap_fdatawrite_range mm/filemap.c:430 [inline]
 filemap_write_and_wait_range+0xb6/0x1f0 mm/filemap.c:685
 filemap_write_and_wait include/linux/pagemap.h:66 [inline]
 ext4_bmap+0x14e/0x180 fs/ext4/inode.c:3109
 bmap+0x5d/0x90 fs/inode.c:1792
 ioctl_fibmap fs/ioctl.c:77 [inline]
 file_ioctl fs/ioctl.c:328 [inline]
 do_vfs_ioctl+0x1353/0x1560 fs/ioctl.c:883
 __do_sys_ioctl fs/ioctl.c:902 [inline]
 __se_sys_ioctl+0x81/0x150 fs/ioctl.c:890
 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:890
 x64_sys_call+0x155d/0x2d30 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff88408f28 of 8 bytes by task 16070 on cpu 1:
 wb_domain_writeout_add mm/page-writeback.c:563 [inline]
 __wb_writeout_add+0x8a/0x1e0 mm/page-writeback.c:584
 __folio_end_writeback+0x21b/0x4a0 mm/page-writeback.c:3018
 folio_end_writeback+0x74/0x1f0 mm/filemap.c:1608
 ext4_finish_bio+0x47b/0x8f0 fs/ext4/page-io.c:145
 ext4_release_io_end+0x8c/0x1f0 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+0x2d3/0x370 fs/ext4/page-io.c:273
 process_one_work kernel/workqueue.c:3267 [inline]
 process_scheduled_works+0x465/0x990 kernel/workqueue.c:3348
 worker_thread+0x526/0x730 kernel/workqueue.c:3429
 kthread+0x1d1/0x210 kernel/kthread.c:388
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

value changed: 0x000000010002c7e8 -> 0x000000010002c914

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 16070 Comm: kworker/u8:19 Tainted: G        W          6.9.0-syzkaller-01768-ga5131c3fdf26 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
Workqueue: ext4-rsv-conversion ext4_end_io_rsv_work
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