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BUG: KCSAN: data-race in ktime_get_ts64 / timekeeping_update_from_shadow

write to 0xffffffff893da4c8 of 304 bytes by interrupt on cpu 1:
 timekeeping_update_from_shadow+0x40d/0x440 kernel/time/timekeeping.c:835
 __timekeeping_advance+0xa68/0xc10 kernel/time/timekeeping.c:2614
 timekeeping_advance kernel/time/timekeeping.c:2622 [inline]
 update_wall_time+0x21/0x50 kernel/time/timekeeping.c:2632
 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:2032 [inline]
 __hrtimer_run_queues+0x1f8/0x510 kernel/time/hrtimer.c:2096
 hrtimer_interrupt+0x257/0x810 kernel/time/hrtimer.c:2215
 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:95 [inline]
 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:188 [inline]
 _raw_spin_unlock_irq+0x12/0x30 kernel/locking/spinlock.c:206
 spin_unlock_irq include/linux/spinlock.h:402 [inline]
 filemap_remove_folio+0x75/0x1d0 mm/filemap.c:258
 truncate_inode_folio+0x42/0x50 mm/truncate.c:176
 shmem_undo_range+0x27f/0xb60 mm/shmem.c:1155
 shmem_truncate_range mm/shmem.c:1287 [inline]
 shmem_evict_inode+0x132/0x520 mm/shmem.c:1417
 evict+0x2a5/0x510 fs/inode.c:825
 iput_final fs/inode.c:2019 [inline]
 iput+0x430/0x5a0 fs/inode.c:2068
 dentry_unlink_inode+0x24a/0x260 fs/dcache.c:479
 dentry_kill+0x184/0x500 fs/dcache.c:826
 finish_dput+0x16/0x1d0 fs/dcache.c:1001
 dput+0x48/0x50 fs/dcache.c:1042
 __fput+0x43e/0x630 fs/file_table.c:520
 ____fput+0x1c/0x30 fs/file_table.c:540
 task_work_run+0x130/0x1a0 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:70 [inline]
 exit_to_user_mode_loop+0x1e4/0x8c0 kernel/entry/common.c:101
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
 do_syscall_64+0x23c/0x3c0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff893da4e8 of 8 bytes by task 3287 on cpu 0:
 timekeeping_cycles_to_ns kernel/time/timekeeping.c:450 [inline]
 timekeeping_get_ns kernel/time/timekeeping.c:455 [inline]
 ktime_get_ts64+0x155/0x350 kernel/time/timekeeping.c:1116
 poll_select_set_timeout fs/select.c:282 [inline]
 do_pselect fs/select.c:762 [inline]
 __do_sys_pselect6 fs/select.c:809 [inline]
 __se_sys_pselect6+0x176/0x2a0 fs/select.c:800
 __x64_sys_pselect6+0x78/0x90 fs/select.c:800
 x64_sys_call+0x8d5/0x3020 arch/x86/include/generated/asm/syscalls_64.h:271
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0031c309081e1026 -> 0x00325b9f884d73ec

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3287 Comm: syz-executor Tainted: G        W           syzkaller #0 PREEMPT(lazy) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
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