KCSAN: data-race in ktime_get_coarse_ts64 / timekeeping_update_from

ID	Workflow	Result	Correct	Bug	Created	Started	Finished	Revision	Error
0d917c8f	assessment-security	DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ✅ UserNamespace: ✅ VMGuestTrigger: ❌ VMHostTrigger: ❌	❓	KCSAN: data-race in ktime_get_coarse_ts64 / timekeeping_update_from_shadow	2026/05/30 17:33	2026/05/30 17:33	2026/05/30 18:19	6b4a8443
1f8ca214	assessment-security		💥	KCSAN: data-race in ktime_get_coarse_ts64 / timekeeping_update_from_shadow	2026/05/14 11:16	2026/05/14 11:16	2026/05/14 11:17	6ccb967e	failed to run ["git" "pull" "origin" "HEAD" "--depth=1" "--allow-unrelated-histories"]: exit status 128 From /app/workdir/repo/linux * branch HEAD -> FETCH_HEAD Updating files: ... truncated to first 200 bytes; open job for full error
92032cb3	assessment-kcsan	Benign: ✅ Confident: ✅	❓	KCSAN: data-race in ktime_get_coarse_ts64 / timekeeping_update_from_shadow	2026/04/21 22:23	2026/04/21 22:23	2026/04/21 22:25	0b6ab7ec

Kernel	Title	Rank 🛈	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in ktime_get_coarse_ts64 / timekeeping_update_from_shadow (2) race:benign prio:high kernel	6				1	30d	30d	0/29	moderation: reported on 2026/07/03 06:25

Kernel

Title

Rank 🛈

upstream

KCSAN: data-race in ktime_get_coarse_ts64 / timekeeping_update_from_shadow (2) race:benign prio:high kernel

30d

0/29

moderation: reported on 2026/07/03 06:25

================================================================== BUG: KCSAN: data-race in ktime_get_coarse_ts64 / timekeeping_update_from_shadow write to 0xffffffff895d8488 of 304 bytes by interrupt on cpu 1: 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 native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline] pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:62 arch_safe_halt arch/x86/kernel/process.c:766 [inline] default_idle+0x9/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x3b/0x60 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:199 [inline] do_idle+0x17f/0x2b0 kernel/sched/idle.c:352 cpu_startup_entry+0x24/0x30 kernel/sched/idle.c:451 start_secondary+0x95/0xa0 arch/x86/kernel/smpboot.c:312 common_startup_64+0x13e/0x147 read to 0xffffffff895d84f8 of 4 bytes by task 4851 on cpu 0: tk_xtime_coarse kernel/time/timekeeping.c:212 [inline] ktime_get_coarse_ts64+0x6d/0x120 kernel/time/timekeeping.c:2685 ktime_get_coarse include/linux/timekeeping.h:133 [inline] ktime_get_coarse_ns include/linux/timekeeping.h:139 [inline] ____bpf_ktime_get_coarse_ns kernel/bpf/helpers.c:204 [inline] bpf_ktime_get_coarse_ns+0x39/0xb0 kernel/bpf/helpers.c:202 bpf_prog_ce3dfd7f9330a559+0x1e/0x29 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+0x158/0x350 net/core/flow_dissector.c:1024 bpf_prog_test_run_flow_dissector+0x25d/0x360 net/bpf/test_run.c:1525 bpf_prog_test_run+0x204/0x340 kernel/bpf/syscall.c:4742 __sys_bpf+0x52e/0x7e0 kernel/bpf/syscall.c:6266 __do_sys_bpf kernel/bpf/syscall.c:6361 [inline] __se_sys_bpf kernel/bpf/syscall.c:6359 [inline] __x64_sys_bpf+0x41/0x50 kernel/bpf/syscall.c:6359 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/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f value changed: 0x1972605a -> 0x1a0c2809 Reported by Kernel Concurrency Sanitizer on: CPU: 0 UID: 0 PID: 4851 Comm: syz.6.270 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 ==================================================================

Crashes (1):
Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Assets (help?)	Manager	Title
2026/04/21 22:23	upstream	4ee64205ffaa	0b6ab7ec	.config	console log	report			info	[disk image] [vmlinux] [kernel image]	ci2-upstream-kcsan-gce	KCSAN: data-race in ktime_get_coarse_ts64 / timekeeping_update_from_shadow

Crashes (1):

Assets (help?)