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BUG: KCSAN: data-race in ktime_get_coarse_real_ts64_mg / timekeeping_update_from_shadow

write to 0xffffffff893a8488 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+0x6f/0x80 arch/x86/kernel/apic/apic.c:1061
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
 __preempt_count_dec_and_test arch/x86/include/asm/preempt.h:95 [inline]
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:179 [inline]
 _raw_spin_unlock_irqrestore+0x1a/0x30 kernel/locking/spinlock.c:198
 __unix_dgram_recvmsg+0x3a7/0x870 net/unix/af_unix.c:2612
 unix_dgram_recvmsg+0x7e/0x90 net/unix/af_unix.c:2686
 sock_recvmsg_nosec+0xc2/0xf0 net/socket.c:1137
 ____sys_recvmsg+0x26f/0x280 net/socket.c:2916
 ___sys_recvmsg+0x11f/0x3b0 net/socket.c:2960
 do_recvmmsg+0x1ef/0x560 net/socket.c:3055
 __sys_recvmmsg net/socket.c:3129 [inline]
 __do_sys_recvmmsg net/socket.c:3152 [inline]
 __se_sys_recvmmsg net/socket.c:3145 [inline]
 __x64_sys_recvmmsg+0xe5/0x170 net/socket.c:3145
 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+0x12c/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff893a84f8 of 4 bytes by task 3743 on cpu 1:
 tk_xtime_coarse kernel/time/timekeeping.c:212 [inline]
 ktime_get_coarse_real_ts64_mg+0x89/0x1a0 kernel/time/timekeeping.c:2606
 inode_set_ctime_current+0x43/0x8c0 fs/inode.c:2836
 simple_inode_init_ts+0x19/0x70 fs/libfs.c:2124
 __shmem_get_inode mm/shmem.c:3085 [inline]
 shmem_get_inode+0x2b6/0x790 mm/shmem.c:3175
 shmem_symlink+0x8b/0x3b0 mm/shmem.c:4093
 vfs_symlink+0x106/0x220 fs/namei.c:5643
 filename_symlinkat+0xe8/0x2b0 fs/namei.c:5668
 __do_sys_symlinkat fs/namei.c:5688 [inline]
 __se_sys_symlinkat+0x43/0x1b0 fs/namei.c:5683
 __x64_sys_symlinkat+0x43/0x50 fs/namei.c:5683
 x64_sys_call+0x2b7d/0x3020 arch/x86/include/generated/asm/syscalls_64.h:267
 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: 0x181332b0 -> 0x18abc930

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3743 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
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