KCSAN: data-race in clockevents_program_event / print_tickdevice (14)

Status: moderation: reported on 2026/04/25 15:58
Subsystems: kernel
Labels: prio:low
[Documentation on labels]
Reported-by: syzbot+00e5a73d76c701febd2a@syzkaller.appspotmail.com
First crash: 101d, last: 1d07h
✨ AI Jobs (2)
ID Workflow Result Correct Bug Created Started Finished Revision Error
a9760286 assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ KCSAN: data-race in clockevents_program_event / print_tickdevice (14) 2026/05/25 17:23 2026/05/25 17:23 2026/05/25 18:02 c69befb3

			
		
0d0e8281 assessment-kcsan Benign: ✅ Confident: ✅ KCSAN: data-race in clockevents_program_event / print_tickdevice (14) 2026/04/25 15:58 2026/04/25 15:58 2026/04/25 16:17 9c2d0995

			
		
Similar bugs (13)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in clockevents_program_event / print_tickdevice (8) kernel 6 1 959d 959d 0/29 auto-obsoleted due to no activity on 2024/01/23 08:37
upstream KCSAN: data-race in clockevents_program_event / print_tickdevice (6) kernel 6 28 1145d 1437d 0/29 auto-obsoleted due to no activity on 2023/07/21 02:50
upstream KCSAN: data-race in clockevents_program_event / print_tickdevice (11) kernel 6 1 489d 489d 0/29 auto-obsoleted due to no activity on 2025/05/27 18:27
upstream KCSAN: data-race in clockevents_program_event / print_tickdevice (7) kernel 6 2 1012d 1013d 0/29 auto-obsoleted due to no activity on 2023/11/30 21:56
upstream KCSAN: data-race in clockevents_program_event / print_tickdevice (5) kernel 6 7 1484d 1510d 0/29 auto-closed as invalid on 2022/08/15 19:00
upstream KCSAN: data-race in clockevents_program_event / print_tickdevice (2) kernel 6 1 1845d 1845d 0/29 auto-closed as invalid on 2021/08/19 20:40
upstream KCSAN: data-race in clockevents_program_event / print_tickdevice (10) kernel 6 2 704d 710d 0/29 auto-obsoleted due to no activity on 2024/10/04 08:26
upstream KCSAN: data-race in clockevents_program_event / print_tickdevice (9) kernel 6 1 847d 847d 0/29 auto-obsoleted due to no activity on 2024/05/13 19:49
upstream KCSAN: data-race in clockevents_program_event / print_tickdevice (4) kernel 6 1 1634d 1634d 0/29 auto-closed as invalid on 2022/03/19 14:36
upstream KCSAN: data-race in clockevents_program_event / print_tickdevice kernel 6 1 1929d 1925d 0/29 auto-closed as invalid on 2021/05/28 09:07
upstream KCSAN: data-race in clockevents_program_event / print_tickdevice (13) kernel 6 1 225d 225d 0/29 auto-obsoleted due to no activity on 2026/02/16 14:17
upstream KCSAN: data-race in clockevents_program_event / print_tickdevice (3) kernel 6 5 1735d 1766d 0/29 auto-closed as invalid on 2021/12/08 10:38
upstream KCSAN: data-race in clockevents_program_event / print_tickdevice (12) kernel 6 4 291d 392d 0/29 auto-obsoleted due to no activity on 2025/12/11 22:50

Sample crash report:
==================================================================
BUG: KCSAN: data-race in clockevents_program_event / print_tickdevice

write to 0xffff888237c179e0 of 8 bytes by task 10604 on cpu 0:
 clockevents_program_event+0x46/0x340 kernel/time/clockevents.c:347
 tick_program_event+0x79/0xc0 kernel/time/tick-oneshot.c:48
 hrtimer_rearm_event kernel/time/hrtimer.c:707 [inline]
 hrtimer_rearm kernel/time/hrtimer.c:2141 [inline]
 __hrtimer_rearm_deferred+0x569/0x650 kernel/time/hrtimer.c:2161
 hrtimer_rearm_deferred_tif include/linux/hrtimer_rearm.h:53 [inline]
 hrtimer_rearm_deferred include/linux/hrtimer_rearm.h:62 [inline]
 irqentry_exit_to_kernel_mode_after_preempt include/linux/irq-entry-common.h:505 [inline]
 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:542 [inline]
 irqentry_exit+0x58f/0x610 kernel/entry/common.c:167
 sysvec_apic_timer_interrupt+0x44/0x80 arch/x86/kernel/apic/apic.c:1062
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
 do_jit+0x20b1/0x8c10 arch/x86/net/bpf_jit_comp.c:1835
 bpf_int_jit_compile+0x587/0xdc0 arch/x86/net/bpf_jit_comp.c:3929
 bpf_prog_jit_compile kernel/bpf/core.c:2627 [inline]
 __bpf_prog_select_runtime+0x461/0x7c0 kernel/bpf/core.c:2696
 bpf_prog_select_runtime+0x1f/0x30 kernel/bpf/core.c:2736
 bpf_migrate_filter net/core/filter.c:1318 [inline]
 bpf_prepare_filter+0xbe7/0xc40 net/core/filter.c:1366
 bpf_prog_create_from_user+0x1e3/0x260 net/core/filter.c:1460
 seccomp_prepare_filter kernel/seccomp.c:701 [inline]
 seccomp_prepare_user_filter kernel/seccomp.c:738 [inline]
 seccomp_set_mode_filter kernel/seccomp.c:1990 [inline]
 do_seccomp+0x5ef/0xa40 kernel/seccomp.c:2110
 __do_sys_seccomp kernel/seccomp.c:2129 [inline]
 __se_sys_seccomp kernel/seccomp.c:2126 [inline]
 __x64_sys_seccomp+0x40/0x50 kernel/seccomp.c:2126
 x64_sys_call+0x3f9/0x3020 arch/x86/include/generated/asm/syscalls_64.h:318
 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 0xffff888237c179e0 of 8 bytes by task 10606 on cpu 1:
 print_tickdevice+0x144/0x340 kernel/time/timer_list.c:200
 timer_list_show+0x6c/0x170 kernel/time/timer_list.c:292
 seq_read_iter+0x5f6/0x8f0 fs/seq_file.c:273
 proc_reg_read_iter+0x110/0x180 fs/proc/inode.c:299
 copy_splice_read+0x47a/0x6b0 fs/splice.c:362
 do_splice_read fs/splice.c:980 [inline]
 splice_direct_to_actor+0x261/0x680 fs/splice.c:1084
 do_splice_direct_actor fs/splice.c:1202 [inline]
 do_splice_direct+0x119/0x1a0 fs/splice.c:1228
 do_sendfile+0x37d/0x640 fs/read_write.c:1371
 __do_sys_sendfile64 fs/read_write.c:1432 [inline]
 __se_sys_sendfile64 fs/read_write.c:1418 [inline]
 __x64_sys_sendfile64+0x105/0x150 fs/read_write.c:1418
 x64_sys_call+0x2dc4/0x3020 arch/x86/include/generated/asm/syscalls_64.h:41
 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: 0x7fffffffffffffff -> 0x0000002fa3f3bb5f

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 10606 Comm: syz.1.2650 Tainted: G        W           syzkaller #0 PREEMPT(lazy) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
==================================================================

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/03 09:23 upstream 075b74841bd0 e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in clockevents_program_event / print_tickdevice
2026/06/29 15:30 upstream dc59e4fea9d8 6a0c72dc .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in clockevents_program_event / print_tickdevice
2026/05/31 03:04 upstream 9d87d0fc8c8e 6b4a8443 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in clockevents_program_event / print_tickdevice
2026/05/01 12:00 upstream 26fd6bff2c05 753c55b9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in clockevents_program_event / print_tickdevice
2026/04/25 15:58 upstream 27d128c1cff6 9c2d0995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in clockevents_program_event / print_tickdevice
* Struck through repros no longer work on HEAD.