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BUG: KCSAN: data-race in wq_worker_tick / wq_worker_tick

read-write to 0xffff8881000734b8 of 8 bytes by interrupt on cpu 0:
 wq_worker_tick+0x60/0x230 kernel/workqueue.c:1478
 sched_tick+0x11a/0x270 kernel/sched/core.c:5648
 update_process_times+0x15f/0x190 kernel/time/timer.c:2478
 tick_sched_handle kernel/time/tick-sched.c:276 [inline]
 tick_nohz_handler+0x249/0x2d0 kernel/time/tick-sched.c:297
 __run_hrtimer kernel/time/hrtimer.c:1761 [inline]
 __hrtimer_run_queues+0x20f/0x5a0 kernel/time/hrtimer.c:1825
 hrtimer_interrupt+0x21a/0x460 kernel/time/hrtimer.c:1887
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline]
 __sysvec_apic_timer_interrupt+0x5c/0x1d0 arch/x86/kernel/apic/apic.c:1056
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 sysvec_apic_timer_interrupt+0x6f/0x80 arch/x86/kernel/apic/apic.c:1050
 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:95 [inline]
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
 _raw_spin_unlock_irqrestore+0x3c/0x60 kernel/locking/spinlock.c:194
 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
 tty_insert_flip_string_and_push_buffer+0x1aa/0x1f0 drivers/tty/tty_buffer.c:561
 pty_write+0x70/0x90 drivers/tty/pty.c:118
 tty_put_char+0x8c/0xc0 drivers/tty/tty_io.c:3154
 n_tty_process_echo_ops drivers/tty/n_tty.c:647 [inline]
 __process_echoes+0x2f9/0x6b0 drivers/tty/n_tty.c:693
 commit_echoes drivers/tty/n_tty.c:756 [inline]
 n_tty_receive_char+0x588/0x6a0 drivers/tty/n_tty.c:1421
 n_tty_receive_buf_standard+0x473/0x2f10 drivers/tty/n_tty.c:1590
 __receive_buf drivers/tty/n_tty.c:1624 [inline]
 n_tty_receive_buf_common+0x805/0xbe0 drivers/tty/n_tty.c:1723
 n_tty_receive_buf2+0x33/0x40 drivers/tty/n_tty.c:1769
 tty_ldisc_receive_buf+0x66/0xf0 drivers/tty/tty_buffer.c:387
 tty_port_default_receive_buf+0x59/0x90 drivers/tty/tty_port.c:37
 receive_buf drivers/tty/tty_buffer.c:445 [inline]
 flush_to_ldisc+0x145/0x340 drivers/tty/tty_buffer.c:495
 process_one_work kernel/workqueue.c:3236 [inline]
 process_scheduled_works+0x4ce/0x9d0 kernel/workqueue.c:3319
 worker_thread+0x582/0x770 kernel/workqueue.c:3400
 kthread+0x486/0x510 kernel/kthread.c:463
 ret_from_fork+0xda/0x150 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read-write to 0xffff8881000734b8 of 8 bytes by interrupt on cpu 1:
 wq_worker_tick+0x60/0x230 kernel/workqueue.c:1478
 sched_tick+0x11a/0x270 kernel/sched/core.c:5648
 update_process_times+0x15f/0x190 kernel/time/timer.c:2478
 tick_sched_handle kernel/time/tick-sched.c:276 [inline]
 tick_nohz_handler+0x249/0x2d0 kernel/time/tick-sched.c:297
 __run_hrtimer kernel/time/hrtimer.c:1761 [inline]
 __hrtimer_run_queues+0x20f/0x5a0 kernel/time/hrtimer.c:1825
 hrtimer_interrupt+0x21a/0x460 kernel/time/hrtimer.c:1887
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline]
 __sysvec_apic_timer_interrupt+0x5c/0x1d0 arch/x86/kernel/apic/apic.c:1056
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 sysvec_apic_timer_interrupt+0x6f/0x80 arch/x86/kernel/apic/apic.c:1050
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
 is_atomic kernel/kcsan/core.c:260 [inline]
 should_watch kernel/kcsan/core.c:277 [inline]
 check_access kernel/kcsan/core.c:752 [inline]
 __tsan_read8+0xfc/0x190 kernel/kcsan/core.c:1025
 __vlan_group_get_device net/8021q/vlan.h:59 [inline]
 vlan_device_event+0x3fc/0x11b0 net/8021q/vlan.c:427
 notifier_call_chain kernel/notifier.c:85 [inline]
 raw_notifier_call_chain+0x6c/0x1b0 kernel/notifier.c:453
 call_netdevice_notifiers_info+0xae/0x100 net/core/dev.c:2229
 netif_state_change+0x16d/0x1f0 net/core/dev.c:1583
 linkwatch_do_dev+0xb9/0xf0 net/core/link_watch.c:186
 __linkwatch_run_queue+0x582/0x850 net/core/link_watch.c:244
 linkwatch_event+0x40/0x50 net/core/link_watch.c:304
 process_one_work kernel/workqueue.c:3236 [inline]
 process_scheduled_works+0x4ce/0x9d0 kernel/workqueue.c:3319
 worker_thread+0x582/0x770 kernel/workqueue.c:3400
 kthread+0x486/0x510 kernel/kthread.c:463
 ret_from_fork+0xda/0x150 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

value changed: 0x00000000000dbba0 -> 0x00000000000de2b0

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 31 Comm: kworker/u8:1 Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Workqueue: events_unbound linkwatch_event
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