syzbot


KCSAN: data-race in hrtimer_interrupt / print_tickdevice (16)

Status: moderation: reported on 2026/02/09 15:15
Subsystems: kernel
[Documentation on labels]
Reported-by: syzbot+fe1058f12ef7ca496af9@syzkaller.appspotmail.com
First crash: 102d, last: 1d23h
✨ AI Jobs (2)
ID Workflow Result Correct Bug Created Started Finished Revision Error
058e6d8f-794d-47ca-a691-77776660c17e assessment-kcsan Benign: ✅ Confident: ✅ KCSAN: data-race in hrtimer_interrupt / print_tickdevice (16) 2026/02/25 03:30 2026/02/25 03:30 2026/02/25 03:32 305c0ec5cd886e2d13738e28e1b2df9b0ec20fc9
af9da953-4483-416b-91d0-ac34dacefcf6 assessment-kcsan 💥 KCSAN: data-race in hrtimer_interrupt / print_tickdevice (16) 2026/02/09 15:15 2026/02/09 15:15 2026/02/09 15:15 97745f52f5b9361548048f53f0b3b51b9313fedf fork/exec ./syz-agent: no such file or directory
Similar bugs (15)
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 1399d 1423d 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 645d 651d 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 1270d 1294d 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 269d 467d 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 1535d 1700d 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 1835d 1840d 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 996d 996d 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 1472d 1472d 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 525d 595d 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 1343d 1343d 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 880d 893d 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 1750d 1785d 0/29 auto-closed as invalid on 2021/09/10 15:52
upstream KCSAN: data-race in hrtimer_interrupt / print_tickdevice kernel 6 1 1951d 1951d 0/29 auto-closed as invalid on 2021/02/20 21:54
upstream KCSAN: data-race in hrtimer_interrupt / print_tickdevice (12) kernel 6 1 750d 750d 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 1062d 1211d 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 0xffff888237d17ba0 of 8 bytes by interrupt on cpu 1:
 hrtimer_interrupt+0x69/0x850 kernel/time/hrtimer.c:2092
 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
 bpf_stack_slot_alive+0x0/0x440 kernel/bpf/liveness.c:357
 __clean_func_state kernel/bpf/states.c:420 [inline]
 clean_verifier_state kernel/bpf/states.c:486 [inline]
 bpf_is_state_visited+0x4c1/0x27e0 kernel/bpf/states.c:1229
 do_check kernel/bpf/verifier.c:17701 [inline]
 do_check_common+0x109c/0x2bd0 kernel/bpf/verifier.c:18804
 do_check_main kernel/bpf/verifier.c:18887 [inline]
 bpf_check+0x2a87/0x2e70 kernel/bpf/verifier.c:20058
 bpf_prog_load+0xedc/0x1030 kernel/bpf/syscall.c:3082
 __sys_bpf+0x505/0x7e0 kernel/bpf/syscall.c:6248
 __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

read to 0xffff888237d17ba0 of 8 bytes by task 2500 on cpu 0:
 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: 0x000000805c83c82a -> 0x7fffffffffffffff

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 2500 Comm: syz.7.10818 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 (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/05/20 16:50 upstream df685633c3db 62fb93a2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_tickdevice
2026/05/03 12:59 upstream 66edb901bf87 a0d91488 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_tickdevice
2026/03/26 17:34 upstream 0138af2472df 766b6434 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_tickdevice
2026/03/09 18:13 upstream 1f318b96cc84 176bead5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_tickdevice
2026/02/09 15:15 upstream 05f7e89ab973 df949cd9 .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.