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BUG: KCSAN: data-race in __folio_end_writeback / writeout_period

write to 0xffffffff86dc5130 of 8 bytes by interrupt on cpu 0:
 writeout_period+0xa6/0xe0 mm/page-writeback.c:623
 call_timer_fn+0x2e/0x240 kernel/time/timer.c:1421
 expire_timers+0x116/0x240 kernel/time/timer.c:1466
 __run_timers+0x368/0x410 kernel/time/timer.c:1734
 run_timer_softirq+0x56/0x60 kernel/time/timer.c:1749
 __do_softirq+0x158/0x2de kernel/softirq.c:558
 __irq_exit_rcu kernel/softirq.c:637 [inline]
 irq_exit_rcu+0x37/0x70 kernel/softirq.c:649
 sysvec_apic_timer_interrupt+0x8d/0xb0 arch/x86/kernel/apic/apic.c:1097
 asm_sysvec_apic_timer_interrupt+0x12/0x20
 native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
 arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
 acpi_safe_halt drivers/acpi/processor_idle.c:109 [inline]
 acpi_idle_do_entry drivers/acpi/processor_idle.c:553 [inline]
 acpi_idle_enter+0x282/0x300 drivers/acpi/processor_idle.c:688
 cpuidle_enter_state+0x2b4/0x7d0 drivers/cpuidle/cpuidle.c:237
 cpuidle_enter+0x3c/0x60 drivers/cpuidle/cpuidle.c:351
 call_cpuidle kernel/sched/idle.c:158 [inline]
 cpuidle_idle_call kernel/sched/idle.c:239 [inline]
 do_idle+0x1b2/0x250 kernel/sched/idle.c:306
 cpu_startup_entry+0x15/0x20 kernel/sched/idle.c:403
 rest_init+0xfa/0x100 init/main.c:725
 arch_call_rest_init+0xa/0xb
 start_kernel+0x5e4/0x669 init/main.c:1135
 secondary_startup_64_no_verify+0xb1/0xbb

read to 0xffffffff86dc5130 of 8 bytes by task 2589 on cpu 1:
 wb_domain_writeout_add mm/page-writeback.c:572 [inline]
 __wb_writeout_add mm/page-writeback.c:593 [inline]
 __folio_end_writeback+0x2b3/0x580 mm/page-writeback.c:2821
 folio_end_writeback+0x57/0x130 mm/filemap.c:1605
 end_page_writeback+0x37/0x50 mm/folio-compat.c:25
 ext4_finish_bio+0x3e2/0x430 fs/ext4/page-io.c:143
 ext4_release_io_end+0x98/0x200 fs/ext4/page-io.c:158
 ext4_end_io_end fs/ext4/page-io.c:192 [inline]
 ext4_do_flush_completed_IO fs/ext4/page-io.c:257 [inline]
 ext4_end_io_rsv_work+0x306/0x360 fs/ext4/page-io.c:271
 process_one_work+0x3fc/0x980 kernel/workqueue.c:2298
 worker_thread+0x616/0xa70 kernel/workqueue.c:2445
 kthread+0x2c7/0x2e0 kernel/kthread.c:327
 ret_from_fork+0x1f/0x30

value changed: 0x00000001000451e4 -> 0x0000000100045310

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 2589 Comm: kworker/u4:63 Tainted: G        W         5.16.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: ext4-rsv-conversion ext4_end_io_rsv_work
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