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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
 kcsan_setup_watchpoint+0x3fe/0x410 kernel/kcsan/core.c:705
 should_fail_ex+0x2d/0x230 lib/fault-inject.c:125
 __should_fail_alloc_page+0xfd/0x110 mm/fail_page_alloc.c:42
 prepare_alloc_pages mm/page_alloc.c:4340 [inline]
 __alloc_pages+0x108/0x340 mm/page_alloc.c:4556
 alloc_pages_mpol+0xb1/0x1d0 mm/mempolicy.c:2133
 alloc_pages mm/mempolicy.c:2204 [inline]
 folio_alloc+0xea/0x120 mm/mempolicy.c:2211
 filemap_alloc_folio+0x68/0x220 mm/filemap.c:975
 __filemap_get_folio+0x298/0x5a0 mm/filemap.c:1919
 ext4_da_write_begin+0x2eb/0x550 fs/ext4/inode.c:2885
 generic_perform_write+0x1c9/0x410 mm/filemap.c:3930
 ext4_buffered_write_iter+0x1f6/0x370 fs/ext4/file.c:299
 ext4_file_write_iter+0x297/0xe10
 __kernel_write_iter+0x25f/0x480 fs/read_write.c:523
 dump_emit_page fs/coredump.c:888 [inline]
 dump_user_range+0x25d/0x480 fs/coredump.c:915
 elf_core_dump+0x1a8e/0x1bb0 fs/binfmt_elf.c:2077
 do_coredump+0x102a/0x1890 fs/coredump.c:764
 get_signal+0xdb5/0x10a0 kernel/signal.c:2879
 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+0x9c/0x130 kernel/entry/common.c:225
 irqentry_exit+0x12/0x40 kernel/entry/common.c:328
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:570

read to 0xffffffff87125d70 of 8 bytes by task 11300 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: 0x00000001000328e5 -> 0x0000000100032a11

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 11300 Comm: kworker/u4:49 Not tainted 6.8.0-rc4-syzkaller-00034-g8d3dea210042 #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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