syzbot

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BUG: KCSAN: data-race in ktime_get / timekeeping_update_from_shadow

write to 0xffffffff893c6108 of 280 bytes by interrupt on cpu 0:
 timekeeping_update_from_shadow+0x2b4/0x2f0 kernel/time/timekeeping.c:753
 __timekeeping_advance+0xa5b/0xbe0 kernel/time/timekeeping.c:2377
 timekeeping_advance kernel/time/timekeeping.c:2385 [inline]
 update_wall_time+0x24/0x90 kernel/time/timekeeping.c:2395
 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:1785 [inline]
 __hrtimer_run_queues+0x218/0x4f0 kernel/time/hrtimer.c:1849
 hrtimer_interrupt+0x269/0x810 kernel/time/hrtimer.c:1911
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline]
 __sysvec_apic_timer_interrupt+0x5f/0x1f0 arch/x86/kernel/apic/apic.c:1062
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
 sysvec_apic_timer_interrupt+0x6f/0x80 arch/x86/kernel/apic/apic.c:1056
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
 unix_dgram_recvmsg+0x12/0x90 net/unix/af_unix.c:2661
 sock_recvmsg_nosec+0xc2/0xf0 net/socket.c:1078
 ____sys_recvmsg+0x26f/0x280 net/socket.c:2810
 ___sys_recvmsg+0x11f/0x3b0 net/socket.c:2854
 do_recvmmsg+0x1ef/0x560 net/socket.c:2949
 __sys_recvmmsg net/socket.c:3023 [inline]
 __do_sys_recvmmsg net/socket.c:3046 [inline]
 __se_sys_recvmmsg net/socket.c:3039 [inline]
 __x64_sys_recvmmsg+0xe5/0x170 net/socket.c:3039
 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/0x370 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff893c6128 of 8 bytes by task 21632 on cpu 1:
 timekeeping_cycles_to_ns kernel/time/timekeeping.c:399 [inline]
 timekeeping_get_ns kernel/time/timekeeping.c:404 [inline]
 ktime_get+0x12e/0x210 kernel/time/timekeeping.c:826
 ktime_get_ns include/linux/timekeeping.h:175 [inline]
 bpf_test_timer_continue+0x155/0x350 net/bpf/test_run.c:72
 bpf_test_run+0x2f8/0x620 net/bpf/test_run.c:427
 bpf_prog_test_run_skb+0x9a4/0xef0 net/bpf/test_run.c:1159
 bpf_prog_test_run+0x204/0x340 kernel/bpf/syscall.c:4722
 __sys_bpf+0x52e/0x7e0 kernel/bpf/syscall.c:6246
 __do_sys_bpf kernel/bpf/syscall.c:6341 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:6339 [inline]
 __x64_sys_bpf+0x41/0x50 kernel/bpf/syscall.c:6339
 x64_sys_call+0x10cb/0x3020 arch/x86/include/generated/asm/syscalls_64.h:322
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x370 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00185571f895e259 -> 0x0018ee0aa8661294

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 21632 Comm: syz.5.3922 Tainted: G        W           syzkaller #0 PREEMPT(full) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
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