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BUG: KCSAN: data-race in ktime_get_ts64 / timekeeping_advance

write to 0xffffffff8624b2c8 of 280 bytes by interrupt on cpu 0:
 timekeeping_advance+0x88e/0xd80 include/linux/string.h:380
 update_wall_time+0x19/0x20 kernel/time/timekeeping.c:2137
 tick_do_update_jiffies64+0x1a4/0x250 kernel/time/tick-sched.c:94
 tick_sched_do_timer+0xd4/0xe0 kernel/time/tick-sched.c:138
 tick_sched_timer+0x43/0xe0 kernel/time/tick-sched.c:1303
 __run_hrtimer kernel/time/hrtimer.c:1517 [inline]
 __hrtimer_run_queues+0x274/0x5f0 kernel/time/hrtimer.c:1579
 hrtimer_interrupt+0x22a/0x480 kernel/time/hrtimer.c:1641
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline]
 smp_apic_timer_interrupt+0xdc/0x280 arch/x86/kernel/apic/apic.c:1135
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829
 __read_once_size include/linux/compiler.h:232 [inline]
 compound_head include/linux/page-flags.h:174 [inline]
 virt_to_head_page include/linux/mm.h:733 [inline]
 virt_to_cache mm/slab.h:472 [inline]
 __ksize+0x3f/0xc0 mm/slab.c:4226
 __alloc_skb+0xdb/0x360 net/core/skbuff.c:216
 alloc_skb include/linux/skbuff.h:1049 [inline]
 alloc_skb_with_frags+0x8c/0x3d0 net/core/skbuff.c:5664
 sock_alloc_send_pskb+0x4f5/0x530 net/core/sock.c:2242
 sock_alloc_send_skb+0x3b/0x50 net/core/sock.c:2259
 __ip_append_data.isra.0+0x10a5/0x1e10 net/ipv4/ip_output.c:1091
 ip_make_skb+0x16c/0x1c0 net/ipv4/ip_output.c:1628
 udp_sendmsg+0x151f/0x1900 net/ipv4/udp.c:1173
 udpv6_sendmsg+0xe70/0x1d30 net/ipv6/udp.c:1284
 inet6_sendmsg+0x6d/0x90 net/ipv6/af_inet6.c:576
 sock_sendmsg_nosec net/socket.c:639 [inline]
 sock_sendmsg+0x9f/0xc0 net/socket.c:659
 ____sys_sendmsg+0x212/0x4d0 net/socket.c:2330
 ___sys_sendmsg+0xb5/0x100 net/socket.c:2384
 __sys_sendmmsg+0x123/0x350 net/socket.c:2474
 __do_sys_sendmmsg net/socket.c:2503 [inline]
 __se_sys_sendmmsg net/socket.c:2500 [inline]
 __x64_sys_sendmmsg+0x64/0x80 net/socket.c:2500
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffffffff8624b348 of 16 bytes by task 11831 on cpu 1:
 ktime_get_ts64+0x15a/0x2c0 kernel/time/timekeeping.c:893
 posix_ktime_get_ts+0x1f/0x30 kernel/time/posix-timers.c:192
 __do_sys_clock_gettime kernel/time/posix-timers.c:1070 [inline]
 __se_sys_clock_gettime kernel/time/posix-timers.c:1060 [inline]
 __x64_sys_clock_gettime+0xb3/0x170 kernel/time/posix-timers.c:1060
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 11831 Comm: syz-executor.3 Not tainted 5.5.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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