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

Status: moderation: reported on 2026/02/09 15:15
Subsystems: kernel
Labels: prio:low
[Documentation on labels]
Reported-by: syzbot+fe1058f12ef7ca496af9@syzkaller.appspotmail.com
First crash: 112d, last: 2d10h
▶ ▼ ✨ AI Jobs (3)
ID Workflow Result Correct Bug Created Started Finished Revision Error
75aee22b-2583-45bc-81e2-a837a23cc39d assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ KCSAN: data-race in hrtimer_interrupt / print_tickdevice (16) 2026/05/25 17:05 2026/05/25 17:05 2026/05/25 17:34 c69befb30ac10e158cc9d1557b508ee3f0eca1de
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 1409d 1433d 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 655d 662d 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 1280d 1304d 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 279d 477d 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 1545d 1710d 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 1846d 1850d 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 1006d 1006d 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 1482d 1482d 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 536d 605d 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 1353d 1353d 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 890d 904d 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 1760d 1795d 0/29 auto-closed as invalid on 2021/09/10 15:52
upstream KCSAN: data-race in hrtimer_interrupt / print_tickdevice kernel 6 1 1962d 1962d 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 761d 761d 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 1072d 1222d 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 0xffff888237c17ba0 of 8 bytes by interrupt on cpu 0:
 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
 crng_make_state+0xc1/0x200 drivers/char/random.c:384
 get_random_bytes_user+0x92/0x2b0 drivers/char/random.c:445
 __do_sys_getrandom drivers/char/random.c:1406 [inline]
 __se_sys_getrandom drivers/char/random.c:1380 [inline]
 __x64_sys_getrandom+0xcf/0x1a0 drivers/char/random.c:1380
 x64_sys_call+0x2a28/0x3020 arch/x86/include/generated/asm/syscalls_64.h:319
 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 25293 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: 0x000000d836839047 -> 0x000000d836940e57

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 25293 Comm: syz.6.6404 Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
==================================================================

Crashes (7):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/05/30 14:16 upstream f5e5d3509bff 6b4a8443 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_tickdevice
2026/05/23 04:21 upstream 79bd2dded182 c69befb3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_tickdevice
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.