syzbot


KCSAN: data-race in clockevents_program_event / print_tickdevice (13)

Status: moderation: reported on 2025/12/22 14:17
Subsystems: kernel
[Documentation on labels]
Reported-by: syzbot+6c4f83ab248e1807a405@syzkaller.appspotmail.com
First crash: 10d, last: 10d
Similar bugs (12)
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 745d 745d 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 931d 1223d 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 275d 275d 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 798d 799d 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 1270d 1296d 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 1631d 1631d 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 490d 496d 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 633d 633d 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 1419d 1419d 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 1715d 1711d 0/29 auto-closed as invalid on 2021/05/28 09:07
upstream KCSAN: data-race in clockevents_program_event / print_tickdevice (3) kernel 6 5 1521d 1551d 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 77d 178d 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 0xffff888237c17b58 of 8 bytes by task 15527 on cpu 0:
 clockevents_program_event+0x3e/0x4c0 kernel/time/clockevents.c:313
 tick_program_event+0x79/0xc0 kernel/time/tick-oneshot.c:48
 __hrtimer_reprogram kernel/time/hrtimer.c:678 [inline]
 hrtimer_reprogram+0x1d4/0x220 kernel/time/hrtimer.c:861
 hrtimer_start_range_ns+0x6b1/0x740 kernel/time/hrtimer.c:1323
 hrtimer_start_expires include/linux/hrtimer.h:273 [inline]
 hrtimer_sleeper_start_expires kernel/time/hrtimer.c:2039 [inline]
 do_nanosleep+0x79/0x330 kernel/time/hrtimer.c:2113
 hrtimer_nanosleep+0x1b8/0x360 kernel/time/hrtimer.c:2163
 common_nsleep+0x62/0x80 kernel/time/posix-timers.c:1352
 __do_sys_clock_nanosleep kernel/time/posix-timers.c:1398 [inline]
 __se_sys_clock_nanosleep+0x21a/0x250 kernel/time/posix-timers.c:1375
 __x64_sys_clock_nanosleep+0x55/0x70 kernel/time/posix-timers.c:1375
 x64_sys_call+0x2734/0x3000 arch/x86/include/generated/asm/syscalls_64.h:231
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xca/0x2b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888237c17b58 of 8 bytes by task 15546 on cpu 1:
 print_tickdevice+0x142/0x340 kernel/time/timer_list.c:206
 timer_list_show+0x6c/0x170 kernel/time/timer_list.c:298
 seq_read_iter+0x636/0x950 fs/seq_file.c:272
 proc_reg_read_iter+0x110/0x180 fs/proc/inode.c:299
 copy_splice_read+0x442/0x660 fs/splice.c:363
 do_splice_read fs/splice.c:982 [inline]
 splice_direct_to_actor+0x26f/0x680 fs/splice.c:1086
 do_splice_direct_actor fs/splice.c:1204 [inline]
 do_splice_direct+0xda/0x150 fs/splice.c:1230
 do_sendfile+0x380/0x650 fs/read_write.c:1370
 __do_sys_sendfile64 fs/read_write.c:1431 [inline]
 __se_sys_sendfile64 fs/read_write.c:1417 [inline]
 __x64_sys_sendfile64+0x105/0x150 fs/read_write.c:1417
 x64_sys_call+0x2db1/0x3000 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xca/0x2b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000056df16c980 -> 0x00000056df1330e0

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 15546 Comm: syz.5.2744 Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/12/22 14:17 upstream 9448598b22c5 d6526ea3 .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.