BUG: KCSAN: data-race in wq_worker_tick / wq_worker_tick

read-write to 0xffff88810100e0b8 of 8 bytes by interrupt on cpu 0:
 wq_worker_tick+0x63/0x240 kernel/workqueue.c:1474
 sched_tick+0xd2/0x110 kernel/sched/core.c:5609
 update_process_times+0x15a/0x180 kernel/time/timer.c:2524
 tick_sched_handle kernel/time/tick-sched.c:276 [inline]
 tick_nohz_handler+0x250/0x2d0 kernel/time/tick-sched.c:297
 __run_hrtimer kernel/time/hrtimer.c:1691 [inline]
 __hrtimer_run_queues+0x20d/0x5e0 kernel/time/hrtimer.c:1755
 hrtimer_interrupt+0x210/0x7b0 kernel/time/hrtimer.c:1817
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1026 [inline]
 __sysvec_apic_timer_interrupt+0x5c/0x1a0 arch/x86/kernel/apic/apic.c:1043
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1037 [inline]
 sysvec_apic_timer_interrupt+0x6e/0x80 arch/x86/kernel/apic/apic.c:1037
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
 preempt_count arch/x86/include/asm/preempt.h:26 [inline]
 get_ctx kernel/kcsan/core.c:206 [inline]
 check_access kernel/kcsan/core.c:750 [inline]
 __tsan_read1+0xb6/0x180 kernel/kcsan/core.c:1022
 ext4_do_writepages+0x4b0/0x2130 fs/ext4/inode.c:2646
 ext4_writepages+0x159/0x2e0 fs/ext4/inode.c:2813
 do_writepages+0x1d8/0x480 mm/page-writeback.c:2683
 __writeback_single_inode+0x89/0x850 fs/fs-writeback.c:1658
 writeback_sb_inodes+0x461/0xa30 fs/fs-writeback.c:1954
 wb_writeback+0x262/0x640 fs/fs-writeback.c:2134
 wb_do_writeback fs/fs-writeback.c:2281 [inline]
 wb_workfn+0x1a8/0x940 fs/fs-writeback.c:2321
 process_one_work kernel/workqueue.c:3229 [inline]
 process_scheduled_works+0x483/0x9a0 kernel/workqueue.c:3310
 worker_thread+0x51d/0x6f0 kernel/workqueue.c:3391
 kthread+0x1d1/0x210 kernel/kthread.c:389
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

read-write to 0xffff88810100e0b8 of 8 bytes by interrupt on cpu 1:
 wq_worker_tick+0x63/0x240 kernel/workqueue.c:1474
 sched_tick+0xd2/0x110 kernel/sched/core.c:5609
 update_process_times+0x15a/0x180 kernel/time/timer.c:2524
 tick_sched_handle kernel/time/tick-sched.c:276 [inline]
 tick_nohz_handler+0x250/0x2d0 kernel/time/tick-sched.c:297
 __run_hrtimer kernel/time/hrtimer.c:1691 [inline]
 __hrtimer_run_queues+0x20d/0x5e0 kernel/time/hrtimer.c:1755
 hrtimer_interrupt+0x210/0x7b0 kernel/time/hrtimer.c:1817
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1026 [inline]
 __sysvec_apic_timer_interrupt+0x5c/0x1a0 arch/x86/kernel/apic/apic.c:1043
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1037 [inline]
 sysvec_apic_timer_interrupt+0x6e/0x80 arch/x86/kernel/apic/apic.c:1037
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
 __preempt_count_dec_and_test arch/x86/include/asm/preempt.h:94 [inline]
 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline]
 _raw_spin_unlock_irq+0x2f/0x50 kernel/locking/spinlock.c:202
 spin_unlock_irq include/linux/spinlock.h:401 [inline]
 tag_pages_for_writeback+0x26b/0x2a0 mm/page-writeback.c:2429
 ext4_do_writepages+0x694/0x2130 fs/ext4/inode.c:2660
 ext4_writepages+0x159/0x2e0 fs/ext4/inode.c:2813
 do_writepages+0x1d8/0x480 mm/page-writeback.c:2683
 __writeback_single_inode+0x89/0x850 fs/fs-writeback.c:1658
 writeback_sb_inodes+0x461/0xa30 fs/fs-writeback.c:1954
 wb_writeback+0x262/0x640 fs/fs-writeback.c:2134
 wb_do_writeback fs/fs-writeback.c:2281 [inline]
 wb_workfn+0x1a8/0x940 fs/fs-writeback.c:2321
 process_one_work kernel/workqueue.c:3229 [inline]
 process_scheduled_works+0x483/0x9a0 kernel/workqueue.c:3310
 worker_thread+0x51d/0x6f0 kernel/workqueue.c:3391
 kthread+0x1d1/0x210 kernel/kthread.c:389
 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: 0x0000000001620100 -> 0x0000000001622810

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 2497 Comm: kworker/u8:11 Not tainted 6.12.0-rc1-syzkaller-00046-g7ec462100ef9 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Workqueue: writeback wb_workfn (flush-7:1)
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