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BUG: KCSAN: data-race in ktime_get_coarse_real_ts64_mg / timekeeping_update_from_shadow

write to 0xffffffff893d04c8 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:2614
 timekeeping_advance kernel/time/timekeeping.c:2622 [inline]
 update_wall_time+0x21/0x50 kernel/time/timekeeping.c:2632
 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
 __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
 spin_unlock_irqrestore include/linux/spinlock.h:408 [inline]
 __skb_try_recv_datagram+0xd0/0x2b0 net/core/datagram.c:267
 __unix_dgram_recvmsg+0x257/0x860 net/unix/af_unix.c:2582
 unix_dgram_recvmsg+0x7e/0x90 net/unix/af_unix.c:2681
 sock_recvmsg_nosec+0xc2/0xf0 net/socket.c:1126
 ____sys_recvmsg+0x26f/0x280 net/socket.c:2902
 ___sys_recvmsg+0x11f/0x3a0 net/socket.c:2946
 do_recvmmsg+0x1e5/0x560 net/socket.c:3041
 __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 0xffffffff893d0538 of 4 bytes by task 3290 on cpu 1:
 tk_xtime_coarse kernel/time/timekeeping.c:217 [inline]
 ktime_get_coarse_real_ts64_mg+0x89/0x1a0 kernel/time/timekeeping.c:2688
 inode_set_ctime_current+0x43/0x8e0 fs/inode.c:2895
 shmem_xattr_handler_set+0x1ad/0x230 mm/shmem.c:4264
 __vfs_setxattr+0x2e6/0x310 fs/xattr.c:223
 __vfs_setxattr_noperm+0xdb/0x3f0 fs/xattr.c:257
 __vfs_setxattr_locked+0x105/0x220 fs/xattr.c:318
 vfs_setxattr+0x12c/0x2a0 fs/xattr.c:344
 do_setxattr fs/xattr.c:662 [inline]
 filename_setxattr+0x1c4/0x410 fs/xattr.c:690
 path_setxattrat+0x2c1/0x320 fs/xattr.c:734
 __do_sys_lsetxattr fs/xattr.c:775 [inline]
 __se_sys_lsetxattr fs/xattr.c:771 [inline]
 __x64_sys_lsetxattr+0x71/0x90 fs/xattr.c:771
 x64_sys_call+0x1300/0x3020 arch/x86/include/generated/asm/syscalls_64.h:190
 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: 0x0bb631db -> 0x0c4ec85b

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3290 Comm: udevd Tainted: G        W           syzkaller #0 PREEMPT(lazy) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
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