================================================================== BUG: KCSAN: data-race in ktime_get_mono_fast_ns / update_fast_timekeeper write to 0xffffffff86d4f8c8 of 56 bytes by interrupt on cpu 0: update_fast_timekeeper+0x38/0x70 kernel/time/timekeeping.c:476 timekeeping_update_from_shadow+0x3ab/0x440 kernel/time/timekeeping.c:812 __timekeeping_advance+0xa68/0xc10 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+0x88/0x3d0 kernel/time/tick-sched.c:312 __run_hrtimer kernel/time/hrtimer.c:1930 [inline] __hrtimer_run_queues+0x1f8/0x510 kernel/time/hrtimer.c:1994 hrtimer_interrupt+0x257/0x810 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 console_flush_one_record arch/x86/include/asm/irqflags.h:-1 [inline] console_flush_all+0x513/0x6b0 kernel/printk/printk.c:3343 __console_flush_and_unlock kernel/printk/printk.c:3373 [inline] console_unlock+0xa1/0x280 kernel/printk/printk.c:3413 vprintk_emit+0x3e4/0x600 kernel/printk/printk.c:2479 vprintk_default+0x26/0x30 kernel/printk/printk.c:2494 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82 _printk+0x79/0xa0 kernel/printk/printk.c:2504 br_set_state+0x2b9/0x390 net/bridge/br_stp.c:57 br_init_port+0x5c/0xf0 net/bridge/br_stp_if.c:39 new_nbp+0x22b/0x300 net/bridge/br_if.c:443 br_add_if+0x1e7/0xa60 net/bridge/br_if.c:586 br_add_slave+0x2c/0x40 net/bridge/br_device.c:375 do_set_master+0x37b/0x450 net/core/rtnetlink.c:2986 do_setlink+0x976/0x2890 net/core/rtnetlink.c:3188 rtnl_changelink net/core/rtnetlink.c:3800 [inline] __rtnl_newlink net/core/rtnetlink.c:3973 [inline] rtnl_newlink+0x1086/0x1400 net/core/rtnetlink.c:4110 rtnetlink_rcv_msg+0x64b/0x720 net/core/rtnetlink.c:6997 netlink_rcv_skb+0x11e/0x220 net/netlink/af_netlink.c:2555 rtnetlink_rcv+0x1c/0x30 net/core/rtnetlink.c:7024 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x5a7/0x680 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x5be/0x6f0 net/netlink/af_netlink.c:1899 sock_sendmsg_nosec net/socket.c:787 [inline] __sock_sendmsg net/socket.c:802 [inline] __sys_sendto+0x42e/0x490 net/socket.c:2266 __do_sys_sendto net/socket.c:2273 [inline] __se_sys_sendto net/socket.c:2269 [inline] __x64_sys_sendto+0x76/0x90 net/socket.c:2269 x64_sys_call+0x2d35/0x3020 arch/x86/include/generated/asm/syscalls_64.h:45 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 0xffffffff86d4f8e8 of 8 bytes by task 6307 on cpu 1: timekeeping_cycles_to_ns kernel/time/timekeeping.c:444 [inline] timekeeping_get_ns kernel/time/timekeeping.c:449 [inline] __ktime_get_fast_ns kernel/time/timekeeping.c:497 [inline] ktime_get_mono_fast_ns+0xdf/0x1a0 kernel/time/timekeeping.c:537 ____bpf_ktime_get_ns kernel/bpf/helpers.c:181 [inline] bpf_ktime_get_ns+0xe/0x20 kernel/bpf/helpers.c:178 bpf_prog_160878b8e03077ee+0x4b/0x53 bpf_dispatcher_nop_func include/linux/bpf.h:1402 [inline] __bpf_prog_run include/linux/filter.h:722 [inline] bpf_prog_run include/linux/filter.h:729 [inline] bpf_prog_run_pin_on_cpu include/linux/filter.h:746 [inline] bpf_flow_dissect+0x14f/0x340 net/core/flow_dissector.c:1024 bpf_prog_test_run_flow_dissector+0x25d/0x360 net/bpf/test_run.c:1525 bpf_prog_test_run+0x208/0x340 kernel/bpf/syscall.c:4742 __sys_bpf+0x52e/0x7e0 kernel/bpf/syscall.c:6292 __do_sys_bpf kernel/bpf/syscall.c:6387 [inline] __se_sys_bpf kernel/bpf/syscall.c:6385 [inline] __x64_sys_bpf+0x41/0x50 kernel/bpf/syscall.c:6385 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+0x136/0x3c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f value changed: 0x002ea508a03794ba -> 0x002f33c3b08e10cc Reported by Kernel Concurrency Sanitizer on: CPU: 1 UID: 0 PID: 6307 Comm: syz.5.9104 Tainted: G W syzkaller #0 PREEMPT(lazy) Tainted: [W]=WARN Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 ==================================================================