KCSAN: data-race in hrtimer_interrupt / print_tickdevice (17)

Status: moderation: reported on 2026/10/05 06:47
Subsystems: kernel
Labels: race:benign prio:low
[Documentation on labels]
Reported-by: syzbot+0b91948d3c6b28c0d4c7@syzkaller.appspotmail.com
First crash: 4d10h, last: 4d10h
▶ ▼ ✨ AI Jobs (2)
ID Workflow Result Correct Bug Created Started Finished Revision
2b7df5c9 assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ KCSAN: data-race in hrtimer_interrupt / print_tickdevice (17) 2026/10/07 01:51 2026/10/07 01:51 2026/10/07 02:40 f7710056
0966483e assessment-kcsan Benign: ✅ ❓ KCSAN: data-race in hrtimer_interrupt / print_tickdevice (17) 2026/10/05 06:52 2026/10/05 06:52 2026/10/05 07:16 57bbd979
▶ ▼ Similar bugs (16)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in hrtimer_interrupt / print_tickdevice (6) kernel 6 5 1539d 1563d 0/29 auto-closed as invalid on 2022/08/27 09:49
upstream KCSAN: data-race in hrtimer_interrupt / print_tickdevice (13) kernel 6 2 785d 791d 0/29 auto-obsoleted due to no activity on 2024/09/19 01:50
upstream KCSAN: data-race in hrtimer_interrupt / print_tickdevice (8) kernel 6 3 1410d 1434d 0/29 auto-obsoleted due to no activity on 2023/01/03 04:47
upstream KCSAN: data-race in hrtimer_interrupt / print_tickdevice (15) kernel 6 9 409d 607d 0/29 auto-obsoleted due to no activity on 2025/10/21 07:50
upstream KCSAN: data-race in hrtimer_interrupt / print_tickdevice (4) kernel 6 14 1675d 1840d 0/29 auto-closed as invalid on 2022/04/13 14:16
upstream KCSAN: data-race in hrtimer_interrupt / print_tickdevice (2) kernel 6 3 1975d 1980d 0/29 auto-closed as invalid on 2021/06/16 18:46
upstream KCSAN: data-race in hrtimer_interrupt / print_tickdevice (10) kernel 6 1 1136d 1136d 0/29 auto-obsoleted due to no activity on 2023/10/04 07:33
upstream KCSAN: data-race in hrtimer_interrupt / print_tickdevice (5) kernel 6 2 1612d 1612d 0/29 auto-closed as invalid on 2022/06/15 02:31
upstream KCSAN: data-race in hrtimer_interrupt / print_tickdevice (14) kernel 6 8 665d 735d 0/29 auto-obsoleted due to no activity on 2025/02/06 20:55
upstream KCSAN: data-race in hrtimer_interrupt / print_tickdevice (7) kernel 6 1 1483d 1483d 0/29 auto-obsoleted due to no activity on 2022/10/22 07:07
upstream KCSAN: data-race in hrtimer_interrupt / print_tickdevice (11) kernel 6 2 1020d 1033d 0/29 auto-obsoleted due to no activity on 2024/01/28 02:00
upstream KCSAN: data-race in hrtimer_interrupt / print_tickdevice (3) kernel 6 2 1890d 1925d 0/29 auto-closed as invalid on 2021/09/10 15:52
upstream KCSAN: data-race in hrtimer_interrupt / print_tickdevice kernel 6 1 2091d 2091d 0/29 auto-closed as invalid on 2021/02/20 21:54
upstream KCSAN: data-race in hrtimer_interrupt / print_tickdevice (16) prio:low kernel 6 10 89d 242d 0/29 auto-obsoleted due to no activity on 2026/09/05 17:51
upstream KCSAN: data-race in hrtimer_interrupt / print_tickdevice (12) kernel 6 1 890d 890d 0/29 auto-obsoleted due to no activity on 2024/06/05 19:29
upstream KCSAN: data-race in hrtimer_interrupt / print_tickdevice (9) kernel 6 20 1202d 1351d 0/29 auto-obsoleted due to no activity on 2023/07/30 02:27

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

write to 0xffff888237c179e0 of 8 bytes by interrupt on cpu 0:
 hrtimer_interrupt+0x6e/0x860 kernel/time/hrtimer.c:2229
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline]
 __sysvec_apic_timer_interrupt+0x5f/0x1c0 arch/x86/kernel/apic/apic.c:1068
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
 sysvec_apic_timer_interrupt+0x32/0x80 arch/x86/kernel/apic/apic.c:1062
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674

read to 0xffff888237c179e0 of 8 bytes by task 3923 on cpu 1:
 print_tickdevice+0x144/0x340 kernel/time/timer_list.c:202
 timer_list_show+0x6c/0x170 kernel/time/timer_list.c:294
 seq_read_iter+0x2d9/0x8f0 fs/seq_file.c:231
 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+0x1015/0x2550 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x112/0x360 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000c18ca64ab -> 0x0000000c18cb00eb

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3923 Comm: syz.3.110 Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/10/05 06:46 upstream a90ee4305c4a 57bbd979 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_tickdevice
* Struck through repros no longer work on HEAD.