syzbot

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

write to 0xffffffff893ca4c8 of 304 bytes by interrupt on cpu 0:
 timekeeping_update_from_shadow+0x40d/0x440 kernel/time/timekeeping.c:835
 __timekeeping_advance+0xa68/0xc10 kernel/time/timekeeping.c:2613
 timekeeping_advance kernel/time/timekeeping.c:2621 [inline]
 update_wall_time+0x21/0x50 kernel/time/timekeeping.c:2631
 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
 __put_user_4+0x14/0x30 arch/x86/lib/putuser.S:95
 do_recvmmsg+0x208/0x560 net/socket.c:3047
 __sys_recvmmsg net/socket.c:3115 [inline]
 __do_sys_recvmmsg net/socket.c:3138 [inline]
 __se_sys_recvmmsg net/socket.c:3131 [inline]
 __x64_sys_recvmmsg+0xe5/0x170 net/socket.c:3131
 x64_sys_call+0x80f/0x3020 arch/x86/include/generated/asm/syscalls_64.h:300
 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

read to 0xffffffff893ca4e8 of 8 bytes by task 3287 on cpu 1:
 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_finish+0x1dd/0x440 fs/select.c:313
 do_pselect fs/select.c:771 [inline]
 __do_sys_pselect6 fs/select.c:809 [inline]
 __se_sys_pselect6+0x253/0x2a0 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: 0x0021cf43753be6f0 -> 0x00226f7401effa92

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 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 05/09/2026
==================================================================