syzbot

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BUG: KCSAN: data-race in ktime_get_with_offset / timekeeping_update_from_shadow

write to 0xffffffff893ac488 of 304 bytes by interrupt on cpu 0:
 timekeeping_update_from_shadow+0x40d/0x440 kernel/time/timekeeping.c:829
 __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+0x32/0x80 arch/x86/kernel/apic/apic.c:1061
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697

read to 0xffffffff893ac4a0 of 4 bytes by task 7992 on cpu 1:
 timekeeping_cycles_to_ns kernel/time/timekeeping.c:444 [inline]
 timekeeping_get_ns kernel/time/timekeeping.c:449 [inline]
 ktime_get_with_offset+0x13a/0x260 kernel/time/timekeeping.c:1011
 ktime_get_boottime include/linux/timekeeping.h:106 [inline]
 ktime_get_boottime_ns include/linux/timekeeping.h:195 [inline]
 copy_process+0x193b/0x2370 kernel/fork.c:2405
 kernel_clone+0x1c0/0x5f0 kernel/fork.c:2722
 __do_sys_clone kernel/fork.c:2863 [inline]
 __se_sys_clone kernel/fork.c:2847 [inline]
 __x64_sys_clone+0x143/0x180 kernel/fork.c:2847
 x64_sys_call+0x1222/0x3020 arch/x86/include/generated/asm/syscalls_64.h:57
 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: 0x006cd8be -> 0x006cd8bd

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 7992 Comm: syz-executor Tainted: G        W           syzkaller #0 PREEMPT(lazy) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
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