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BUG: KCSAN: data-race in fprop_new_period / fprop_reflect_period_percpu

read-write to 0xffffffff86ef7d60 of 4 bytes by interrupt on cpu 1:
 fprop_new_period+0xaa/0xe0 lib/flex_proportions.c:79
 writeout_period+0x59/0xe0 mm/page-writeback.c:613
 call_timer_fn+0x37/0x2f0 kernel/time/timer.c:1700
 expire_timers kernel/time/timer.c:1751 [inline]
 __run_timers+0x46c/0x650 kernel/time/timer.c:2022
 run_timer_softirq+0x31/0x40 kernel/time/timer.c:2037
 __do_softirq+0xc4/0x279 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+0x6d/0x80 arch/x86/kernel/apic/apic.c:1076
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:649
 check_access kernel/kcsan/core.c:787 [inline]
 __tsan_read8+0x11d/0x180 kernel/kcsan/core.c:1025
 mas_is_none include/linux/maple_tree.h:507 [inline]
 mas_state_walk+0x121/0x5d0 lib/maple_tree.c:3706
 mt_find+0xc6/0x310 lib/maple_tree.c:6542
 find_vma+0x4b/0x70 mm/mmap.c:1882
 gup_vma_lookup mm/gup.c:1105 [inline]
 __get_user_pages+0x205/0xe40 mm/gup.c:1207
 __get_user_pages_locked mm/gup.c:1507 [inline]
 get_dump_page+0xb7/0x1b0 mm/gup.c:2029
 dump_user_range+0x86/0x480 fs/coredump.c:913
 elf_core_dump+0x1a85/0x1ba0 fs/binfmt_elf.c:2077
 do_coredump+0x102a/0x1890 fs/coredump.c:764
 get_signal+0xdb5/0x10a0 kernel/signal.c:2890
 arch_do_signal_or_restart+0x95/0x4b0 arch/x86/kernel/signal.c:309
 exit_to_user_mode_loop+0x6f/0xe0 kernel/entry/common.c:168
 exit_to_user_mode_prepare+0x6c/0xb0 kernel/entry/common.c:204
 irqentry_exit_to_user_mode+0x9/0x20 kernel/entry/common.c:309
 irqentry_exit+0x12/0x40 kernel/entry/common.c:412
 asm_exc_stack_segment+0x26/0x30 arch/x86/include/asm/idtentry.h:563

read to 0xffffffff86ef7d60 of 4 bytes by task 15242 on cpu 0:
 fprop_reflect_period_percpu+0x22/0x1a0 lib/flex_proportions.c:188
 __fprop_add_percpu lib/flex_proportions.c:219 [inline]
 __fprop_add_percpu_max+0x58/0x180 lib/flex_proportions.c:277
 wb_domain_writeout_add mm/page-writeback.c:560 [inline]
 __wb_writeout_add+0x7e/0x1d0 mm/page-writeback.c:584
 __folio_end_writeback+0x21b/0x4a0 mm/page-writeback.c:2963
 folio_end_writeback+0x74/0x1f0 mm/filemap.c:1598
 ext4_finish_bio+0x45c/0x8c0 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:2627 [inline]
 process_scheduled_works+0x5b8/0xa30 kernel/workqueue.c:2700
 worker_thread+0x525/0x730 kernel/workqueue.c:2781
 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: 0x0000010b -> 0x0000010c

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 15242 Comm: kworker/u4:9 Not tainted 6.7.0-rc7-syzkaller-00029-g8735c7c84d1b #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
Workqueue: ext4-rsv-conversion ext4_end_io_rsv_work
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