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BUG: KCSAN: data-race in __wb_writeout_add / writeout_period

write to 0xffffffff883cff68 of 8 bytes by interrupt on cpu 1:
 writeout_period+0xa6/0xe0 mm/page-writeback.c:614
 call_timer_fn+0x3a/0x300 kernel/time/timer.c:1792
 expire_timers kernel/time/timer.c:1843 [inline]
 __run_timers kernel/time/timer.c:2408 [inline]
 __run_timer_base+0x417/0x640 kernel/time/timer.c:2419
 run_timer_base kernel/time/timer.c:2428 [inline]
 run_timer_softirq+0x45/0x70 kernel/time/timer.c:2439
 __do_softirq+0xc8/0x285 kernel/softirq.c:554
 invoke_softirq kernel/softirq.c:428 [inline]
 __irq_exit_rcu kernel/softirq.c:633 [inline]
 irq_exit_rcu+0x3c/0x90 kernel/softirq.c:645
 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
 __folio_start_writeback+0x0/0x450
 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:2612
 filemap_fdatawrite_wbc+0xdb/0x100 mm/filemap.c:397
 __filemap_fdatawrite_range mm/filemap.c:430 [inline]
 __filemap_fdatawrite mm/filemap.c:436 [inline]
 filemap_flush+0x61/0x90 mm/filemap.c:463
 ext4_alloc_da_blocks+0x50/0x130 fs/ext4/inode.c:3072
 ext4_release_file+0x5f/0x1c0 fs/ext4/file.c:169
 __fput+0x2c1/0x660 fs/file_table.c:422
 ____fput+0x15/0x20 fs/file_table.c:450
 task_work_run+0x13a/0x1a0 kernel/task_work.c:180
 exit_task_work include/linux/task_work.h:38 [inline]
 do_exit+0x5fd/0x1740 kernel/exit.c:878
 do_group_exit+0x102/0x150 kernel/exit.c:1027
 get_signal+0xf2f/0x1080 kernel/signal.c:2911
 arch_do_signal_or_restart+0x95/0x4b0 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop kernel/entry/common.c:105 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 irqentry_exit_to_user_mode+0x94/0x130 kernel/entry/common.c:225
 irqentry_exit+0x12/0x50 kernel/entry/common.c:328
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623

read to 0xffffffff883cff68 of 8 bytes by task 49 on cpu 0:
 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:3017
 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:3254 [inline]
 process_scheduled_works+0x465/0x990 kernel/workqueue.c:3335
 worker_thread+0x526/0x730 kernel/workqueue.c:3416
 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:243

value changed: 0x0000000100007c78 -> 0x0000000100007da4

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 49 Comm: kworker/u8:3 Tainted: G        W          6.8.0-syzkaller-11608-gd95fcdf4961d #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
Workqueue: ext4-rsv-conversion ext4_end_io_rsv_work
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