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BUG: KCSAN: data-race in ktime_get_mono_fast_ns / update_fast_timekeeper

write to 0xffffffff86d4fb88 of 56 bytes by interrupt on cpu 0:
 update_fast_timekeeper+0x38/0x70 kernel/time/timekeeping.c:476
 timekeeping_update_from_shadow+0x3ab/0x440 kernel/time/timekeeping.c:812
 __timekeeping_advance+0xa5d/0xc10 kernel/time/timekeeping.c:2532
 timekeeping_advance kernel/time/timekeeping.c:2540 [inline]
 update_wall_time+0x21/0x50 kernel/time/timekeeping.c:2550
 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+0x8d/0x3d0 kernel/time/tick-sched.c:312
 __run_hrtimer kernel/time/hrtimer.c:1930 [inline]
 __hrtimer_run_queues+0x276/0x4f0 kernel/time/hrtimer.c:1994
 hrtimer_interrupt+0x261/0x850 kernel/time/hrtimer.c:2113
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 __sysvec_apic_timer_interrupt+0x5f/0x1c0 arch/x86/kernel/apic/apic.c:1067
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline]
 sysvec_apic_timer_interrupt+0x6f/0x80 arch/x86/kernel/apic/apic.c:1061
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
 console_flush_one_record arch/x86/include/asm/irqflags.h:-1 [inline]
 console_flush_all+0x540/0x6c0 kernel/printk/printk.c:3343
 __console_flush_and_unlock kernel/printk/printk.c:3373 [inline]
 console_unlock+0xa1/0x280 kernel/printk/printk.c:3413
 vprintk_emit+0x3e4/0x600 kernel/printk/printk.c:2479
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2494
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x79/0xa0 kernel/printk/printk.c:2504
 inode_doinit_use_xattr+0x29e/0x2d0 security/selinux/hooks.c:1403
 inode_doinit_with_dentry+0x59f/0x7b0 security/selinux/hooks.c:1508
 selinux_d_instantiate+0x27/0x40 security/selinux/hooks.c:6658
 security_d_instantiate+0x76/0x90 security/security.c:3704
 d_splice_alias_ops+0x53/0x320 fs/dcache.c:3141
 d_splice_alias+0x1f/0x30 fs/dcache.c:3206
 ext4_lookup+0x1a6/0x3a0 fs/ext4/namei.c:1812
 __lookup_slow+0x19d/0x260 fs/namei.c:1915
 lookup_slow+0x3c/0x60 fs/namei.c:1932
 walk_component fs/namei.c:2278 [inline]
 lookup_last fs/namei.c:2785 [inline]
 path_lookupat+0x2f7/0x500 fs/namei.c:2809
 filename_lookup+0x190/0x390 fs/namei.c:2838
 filename_listxattr fs/xattr.c:963 [inline]
 path_listxattrat+0xd1/0x2b0 fs/xattr.c:993
 __do_sys_llistxattr fs/xattr.c:1012 [inline]
 __se_sys_llistxattr fs/xattr.c:1009 [inline]
 __x64_sys_llistxattr+0x4d/0x60 fs/xattr.c:1009
 x64_sys_call+0x2d09/0x3020 arch/x86/include/generated/asm/syscalls_64.h:196
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff86d4fb98 of 8 bytes by task 4963 on cpu 1:
 timekeeping_cycles_to_ns kernel/time/timekeeping.c:426 [inline]
 timekeeping_get_ns kernel/time/timekeeping.c:449 [inline]
 __ktime_get_fast_ns kernel/time/timekeeping.c:497 [inline]
 ktime_get_mono_fast_ns+0x92/0x1a0 kernel/time/timekeeping.c:537
 ktime_get_boot_fast_ns+0xf/0x40 kernel/time/timekeeping.c:581
 ____bpf_ktime_get_boot_ns kernel/bpf/helpers.c:193 [inline]
 bpf_ktime_get_boot_ns+0xe/0x20 kernel/bpf/helpers.c:190
 bpf_prog_2af77e62765ed1a8+0x23/0x29
 bpf_dispatcher_nop_func include/linux/bpf.h:1402 [inline]
 __bpf_prog_run include/linux/filter.h:711 [inline]
 bpf_prog_run include/linux/filter.h:729 [inline]
 bpf_test_run+0x421/0x620 net/bpf/test_run.c:423
 bpf_prog_test_run_skb+0xab1/0x11c0 net/bpf/test_run.c:1192
 bpf_prog_test_run+0x204/0x340 kernel/bpf/syscall.c:4742
 __sys_bpf+0x52e/0x7e0 kernel/bpf/syscall.c:6266
 __do_sys_bpf kernel/bpf/syscall.c:6361 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:6359 [inline]
 __x64_sys_bpf+0x41/0x50 kernel/bpf/syscall.c:6359
 x64_sys_call+0x10cb/0x3020 arch/x86/include/generated/asm/syscalls_64.h:322
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000031e3fa84da -> 0x00000031e699e7b4

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 4963 Comm: syz.2.258 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
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