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BUG: KCSAN: data-race in __wb_writeout_add / writeout_period

write to 0xffffffff88404f68 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
 __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
 kcsan_setup_watchpoint+0x404/0x410 kernel/kcsan/core.c:705
 sctp_bind_addr_state+0x56/0xf0 net/sctp/bind_addr.c:411
 sctp_copy_local_addr_list+0x166/0x220 net/sctp/protocol.c:162
 sctp_copy_one_addr+0x83/0x410 net/sctp/bind_addr.c:466
 sctp_bind_addr_copy+0x81/0x2b0 net/sctp/bind_addr.c:56
 sctp_assoc_set_bind_addr_from_ep+0xc0/0xd0 net/sctp/associola.c:1588
 sctp_connect_new_asoc+0x1d0/0x3b0 net/sctp/socket.c:1095
 __sctp_connect+0x41d/0x7a0 net/sctp/socket.c:1197
 sctp_connect net/sctp/socket.c:4819 [inline]
 sctp_inet_connect+0xe5/0x100 net/sctp/socket.c:4834
 __sys_connect_file net/socket.c:2048 [inline]
 __sys_connect+0x1a9/0x1c0 net/socket.c:2065
 __do_sys_connect net/socket.c:2075 [inline]
 __se_sys_connect net/socket.c:2072 [inline]
 __x64_sys_connect+0x41/0x50 net/socket.c:2072
 x64_sys_call+0x2929/0x2d30 arch/x86/include/generated/asm/syscalls_64.h:43
 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 0xffffffff88404f68 of 8 bytes by task 28837 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: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: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: 0x0000000100040c4d -> 0x0000000100040d79

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 28837 Comm: kworker/u8:0 Tainted: G        W          6.9.0-rc6-syzkaller-00046-g18daea77cca6 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Workqueue: ext4-rsv-conversion ext4_end_io_rsv_work
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