==================================================================
BUG: KCSAN: data-race in ktime_get_ts64 / timekeeping_update_from_shadow

write to 0xffffffff895fa508 of 320 bytes by interrupt on cpu 1:
 timekeeping_update_from_shadow+0x448/0x480 kernel/time/timekeeping.c:866
 __timekeeping_advance+0xb36/0xcf0 kernel/time/timekeeping.c:2663
 timekeeping_advance kernel/time/timekeeping.c:2671 [inline]
 update_wall_time+0x21/0x50 kernel/time/timekeeping.c:2681
 tick_do_update_jiffies64+0x169/0x1c0 kernel/time/tick-sched.c:149
 tick_sched_do_timer kernel/time/tick-sched.c:253 [inline]
 tick_nohz_handler+0x88/0x380 kernel/time/tick-sched.c:310
 __run_hrtimer kernel/time/hrtimer.c:2074 [inline]
 __hrtimer_run_queues+0x1f8/0x510 kernel/time/hrtimer.c:2131
 hrtimer_interrupt+0x27b/0x860 kernel/time/hrtimer.c:2250
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline]
 __sysvec_apic_timer_interrupt+0x5f/0x1c0 arch/x86/kernel/apic/apic.c:1068
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
 sysvec_apic_timer_interrupt+0x6f/0x80 arch/x86/kernel/apic/apic.c:1062
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
 __preempt_count_dec_and_test arch/x86/include/asm/preempt.h:123 [inline]
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:211 [inline]
 _raw_spin_unlock_irqrestore+0x1a/0x30 kernel/locking/spinlock.c:221
 spin_unlock_irqrestore include/linux/spinlock.h:425 [inline]
 __uart_port_unlock_irqrestore include/linux/serial_core.h:622 [inline]
 univ8250_console_device_unlock+0x36/0x40 drivers/tty/serial/8250/8250_core.c:420
 nbcon_emit_one kernel/printk/nbcon.c:1165 [inline]
 nbcon_kthread_func+0x595/0x690 kernel/printk/nbcon.c:1271
 kthread+0x223/0x270 kernel/kthread.c:436
 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffffffff895fa528 of 8 bytes by task 2986 on cpu 0:
 timekeeping_cycles_to_ns kernel/time/timekeeping.c:477 [inline]
 timekeeping_get_ns kernel/time/timekeeping.c:482 [inline]
 ktime_get_ts64+0x155/0x350 kernel/time/timekeeping.c:1147
 ep_timeout_to_timespec fs/eventpoll.c:2190 [inline]
 __do_sys_epoll_wait fs/eventpoll.c:2838 [inline]
 __se_sys_epoll_wait fs/eventpoll.c:2832 [inline]
 __x64_sys_epoll_wait+0xd9/0x190 fs/eventpoll.c:2832
 x64_sys_call+0x1ce9/0x2550 arch/x86/include/generated/asm/syscalls_64.h:233
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x112/0x360 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0033a4a98bec1998 -> 0x0034d5d68c4ae124

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 2986 Comm: udevd Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
==================================================================