syzbot


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

Status: moderation: reported on 2026/04/25 15:58
Subsystems: kernel
[Documentation on labels]
Reported-by: syzbot+00e5a73d76c701febd2a@syzkaller.appspotmail.com
First crash: 2d00h, last: 2d00h
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision Error
0d0e8281-9116-4168-a65f-f0ac7e466498 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 9c2d0995bb06e7518555bd3b755e327c89b59823
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 860d 860d 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 1046d 1338d 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 390d 390d 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 913d 914d 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 1385d 1411d 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 1746d 1746d 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 605d 611d 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 748d 748d 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 1535d 1535d 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 1830d 1826d 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 126d 126d 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 1636d 1666d 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 192d 293d 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 0xffff888237c17ba0 of 8 bytes by task 17100 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:2039 [inline]
 __hrtimer_rearm_deferred+0x571/0x670 kernel/time/hrtimer.c:2059
 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:513 [inline]
 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:550 [inline]
 irqentry_exit+0x527/0x5b0 kernel/entry/common.c:164
 sysvec_apic_timer_interrupt+0x44/0x80 arch/x86/kernel/apic/apic.c:1061
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
 finish_task_switch+0x132/0x320 kernel/sched/core.c:5244
 context_switch kernel/sched/core.c:5390 [inline]
 __schedule+0x936/0xd20 kernel/sched/core.c:7188
 __schedule_loop kernel/sched/core.c:7267 [inline]
 schedule+0x5e/0xd0 kernel/sched/core.c:7282
 schedule_timeout+0x53/0x180 kernel/time/sleep_timeout.c:75
 unix_wait_for_peer+0x135/0x1a0 net/unix/af_unix.c:1622
 unix_dgram_sendmsg+0x8de/0x1050 net/unix/af_unix.c:2261
 sock_sendmsg_nosec net/socket.c:787 [inline]
 __sock_sendmsg net/socket.c:802 [inline]
 ____sys_sendmsg+0x563/0x5b0 net/socket.c:2698
 ___sys_sendmsg+0x195/0x1e0 net/socket.c:2752
 __sys_sendmmsg+0x185/0x320 net/socket.c:2841
 __do_sys_sendmmsg net/socket.c:2868 [inline]
 __se_sys_sendmmsg net/socket.c:2865 [inline]
 __x64_sys_sendmmsg+0x57/0x70 net/socket.c:2865
 x64_sys_call+0x27aa/0x3020 arch/x86/include/generated/asm/syscalls_64.h:308
 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

read to 0xffff888237c17ba0 of 8 bytes by task 17098 on cpu 1:
 print_tickdevice+0x142/0x340 kernel/time/timer_list.c:204
 timer_list_show+0x6c/0x170 kernel/time/timer_list.c:296
 seq_read_iter+0x636/0x940 fs/seq_file.c:273
 proc_reg_read_iter+0x110/0x180 fs/proc/inode.c:299
 copy_splice_read+0x471/0x6c0 fs/splice.c:362
 do_splice_read fs/splice.c:980 [inline]
 splice_direct_to_actor+0x26e/0x670 fs/splice.c:1084
 do_splice_direct_actor fs/splice.c:1202 [inline]
 do_splice_direct+0x119/0x1a0 fs/splice.c:1228
 do_sendfile+0x382/0x650 fs/read_write.c:1372
 __do_sys_sendfile64 fs/read_write.c:1433 [inline]
 __se_sys_sendfile64 fs/read_write.c:1419 [inline]
 __x64_sys_sendfile64+0x105/0x150 fs/read_write.c:1419
 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+0x12c/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x7fffffffffffffff -> 0x0000006fa15375aa

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 17098 Comm: syz.4.3227 Tainted: G        W           syzkaller #0 PREEMPT(full) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
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.