KCSAN: data-race in wq_worker_tick / wq_worker_tick

Status: moderation: reported on 2023/12/07 10:03
Subsystems: kernel
Labels: prio:low
[Documentation on labels]
Reported-by: syzbot+1f9c6a9361cf67ffc0d9@syzkaller.appspotmail.com
First crash: 1145d, last: 36m
✨ AI Jobs (4)
ID Workflow Result Correct Bug Created Started Finished Revision
828176b6 assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ✅ NetworkTrigger: ✅ PeripheralTrigger: ✅ RemoteTrigger: ✅ Unprivileged: ✅ UserNamespace: ✅ VMGuestTrigger: ✅ VMHostTrigger: ✅ KCSAN: data-race in wq_worker_tick / wq_worker_tick 2026/05/13 05:10 2026/05/13 05:10 2026/05/13 06:07 a0949470
6d2acab0 repro KCSAN: data-race in wq_worker_tick / wq_worker_tick 2026/03/06 03:15 2026/03/06 03:15 2026/03/06 03:17 31e9c887
9f147d12 assessment-kcsan Benign: ✅ Confident: ✅ KCSAN: data-race in wq_worker_tick / wq_worker_tick 2026/02/24 16:13 2026/02/24 16:13 2026/02/24 16:16 305c0ec5
900af779 assessment-kcsan 💥 KCSAN: data-race in wq_worker_tick / wq_worker_tick 2026/01/09 14:24 2026/01/09 14:24 2026/01/09 14:26 9ee25c60

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

read-write to 0xffff8881000c5cd8 of 8 bytes by interrupt on cpu 1:
 wq_worker_tick+0x64/0x240 kernel/workqueue.c:1508
 sched_tick+0xbc/0x1f0 kernel/sched/core.c:5804
 update_process_times+0x15e/0x190 kernel/time/timer.c:2480
 tick_sched_handle kernel/time/tick-sched.c:296 [inline]
 tick_nohz_handler+0x227/0x380 kernel/time/tick-sched.c:317
 __run_hrtimer kernel/time/hrtimer.c:2032 [inline]
 __hrtimer_run_queues+0x1f8/0x510 kernel/time/hrtimer.c:2096
 hrtimer_interrupt+0x257/0x810 kernel/time/hrtimer.c:2215
 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
 rdtsc_ordered arch/x86/include/asm/tsc.h:57 [inline]
 __pvclock_clocksource_read arch/x86/kernel/pvclock.c:77 [inline]
 pvclock_clocksource_read_nowd+0xd/0x90 arch/x86/kernel/pvclock.c:120
 kvm_sched_clock_read+0x11/0x20 arch/x86/kernel/kvmclock.c:113
 sched_clock+0x17/0x60 arch/x86/kernel/tsc.c:297
 trace_clock_local+0x17/0x60 kernel/trace/trace_clock.c:42
 rb_time_stamp kernel/trace/ring_buffer.c:1127 [inline]
 __rb_reserve_next+0xe7/0x6c0 kernel/trace/ring_buffer.c:4735
 rb_reserve_next_event kernel/trace/ring_buffer.c:4928 [inline]
 ring_buffer_lock_reserve+0x68c/0x830 kernel/trace/ring_buffer.c:4987
 __trace_buffer_lock_reserve kernel/trace/trace.h:1676 [inline]
 trace_event_buffer_lock_reserve+0x148/0x300 kernel/trace/trace.c:1924
 trace_event_buffer_reserve+0x120/0x180 kernel/trace/trace_events.c:688
 do_trace_event_raw_event_softirq include/trace/events/irq.h:103 [inline]
 trace_event_raw_event_softirq+0x74/0xd0 include/trace/events/irq.h:103
 __do_trace_softirq_entry include/trace/events/irq.h:128 [inline]
 trace_softirq_entry include/trace/events/irq.h:128 [inline]
 handle_softirqs+0x173/0x280 kernel/softirq.c:621
 do_softirq+0x45/0x60 kernel/softirq.c:523
 __local_bh_enable_ip+0x70/0x80 kernel/softirq.c:450
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 __alloc_skb+0x6b1/0x6f0 net/core/skbuff.c:699
 alloc_skb include/linux/skbuff.h:1384 [inline]
 nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:819 [inline]
 nsim_dev_trap_report drivers/net/netdevsim/dev.c:876 [inline]
 nsim_dev_trap_report_work+0x18b/0x630 drivers/net/netdevsim/dev.c:922
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0x4d4/0x9a0 kernel/workqueue.c:3405
 worker_thread+0x569/0x750 kernel/workqueue.c:3486
 kthread+0x221/0x270 kernel/kthread.c:436
 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read-write to 0xffff8881000c5cd8 of 8 bytes by interrupt on cpu 0:
 wq_worker_tick+0x64/0x240 kernel/workqueue.c:1508
 sched_tick+0xbc/0x1f0 kernel/sched/core.c:5804
 update_process_times+0x15e/0x190 kernel/time/timer.c:2480
 tick_sched_handle kernel/time/tick-sched.c:296 [inline]
 tick_nohz_handler+0x227/0x380 kernel/time/tick-sched.c:317
 __run_hrtimer kernel/time/hrtimer.c:2032 [inline]
 __hrtimer_run_queues+0x1f8/0x510 kernel/time/hrtimer.c:2096
 hrtimer_interrupt+0x257/0x810 kernel/time/hrtimer.c:2215
 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+0x6f/0x80 arch/x86/kernel/apic/apic.c:1062
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
 crng_make_state+0xc1/0x200 drivers/char/random.c:384
 _get_random_bytes+0x85/0x1b0 drivers/char/random.c:396
 get_random_bytes+0x1d/0x30 drivers/char/random.c:427
 eth_random_addr include/linux/etherdevice.h:239 [inline]
 nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:826 [inline]
 nsim_dev_trap_report drivers/net/netdevsim/dev.c:876 [inline]
 nsim_dev_trap_report_work+0x211/0x630 drivers/net/netdevsim/dev.c:922
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0x4d4/0x9a0 kernel/workqueue.c:3405
 worker_thread+0x569/0x750 kernel/workqueue.c:3486
 kthread+0x221/0x270 kernel/kthread.c:436
 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

value changed: 0x00000000011874e0 -> 0x0000000001189bf0

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 12 Comm: kworker/u8:0 Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: events_unbound nsim_dev_trap_report_work
==================================================================

Crashes (721):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/18 07:10 upstream ff68e5f557f6 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/08/17 01:15 upstream dcb68831eac7 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/08/16 07:57 upstream 3eb40771c00a 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/08/15 02:06 upstream dac3e89a2c90 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/08/14 01:01 upstream 3aa1dcaa4f6f b13552fe .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/08/12 18:57 upstream 3d6d817622b0 359b2492 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/08/12 03:23 upstream f5bbbfec59b4 f8d35649 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/08/11 21:18 upstream f5bbbfec59b4 71790083 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/08/11 02:20 upstream d58772d8520c 508909ea .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/08/09 08:41 upstream 06cf61899d64 5d63f80b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/08/08 21:26 upstream a7c7074b58d2 5d63f80b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/08/08 04:31 upstream bcc44b6785f2 5d63f80b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/08/08 02:24 upstream bcc44b6785f2 e4ef95d6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/08/07 18:30 upstream f9a2394a2348 e4ef95d6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/08/07 03:11 upstream fcaeecb8b0cd c38879ea .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/08/06 14:36 upstream 0d8395707651 c38879ea .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/08/05 19:28 upstream 0d8395707651 cd5b1963 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/08/05 05:32 upstream c21bb4193868 52aa2820 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/08/04 00:57 upstream 848acc8ffe1b 9451e17e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/08/03 14:46 upstream 075b74841bd0 6b7c9f71 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/08/01 17:05 upstream 02dc699f83d0 e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/08/01 07:20 upstream 0131b508c0e2 e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/07/31 14:26 upstream 8ba098e6b6ff 7664cf44 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/07/31 08:40 upstream 3708dd948844 aaffb173 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/07/29 11:46 upstream fc02acf6ac0c 19622d9d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/07/28 01:41 upstream 62cc90241548 45ae1df4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/07/23 07:05 upstream 4539944e5151 881ce5c2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/07/20 23:10 upstream 1590cf032971 de6a700d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/07/20 08:15 upstream 82a47586c0b9 72524a66 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/07/19 13:45 upstream c6859eed755d 72524a66 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/07/19 00:25 upstream 1229e2e57a5c 72524a66 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/07/16 14:59 upstream 37e2f878a7a6 71b49442 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/07/14 09:04 upstream 3b029c035b34 2130f682 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/07/10 20:47 upstream d96fcfe1b7f9 99e64375 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/07/09 22:17 upstream 2c7c88a412aa a0c310a3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/07/09 04:03 upstream 0e35b9b6ec0f b9f1ceaa .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/07/06 22:48 upstream 8cdeaa50eae8 88b240e4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/07/03 00:07 upstream 4a50a141f05a 2b70b115 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/07/01 16:10 upstream 665159e24674 00a5cf1c .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/06/27 09:07 upstream 5a66900afbd6 fb92f11c .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/06/25 04:44 upstream ab9de95c9cf9 cfa969bf .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/06/21 07:21 upstream 390d73adf896 43bfcdb0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/05/13 03:24 upstream c21b90f77687 a0949470 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/03/05 22:04 upstream c107785c7e8d d20b04c8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/02/24 08:01 upstream 7dff99b35460 41d2fa6a .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2026/01/09 06:31 upstream 623fb9912f6a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2023/12/01 12:41 upstream e8f60209d6cf f819d6f7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
2023/11/28 23:33 upstream 18d46e76d7c2 1adfb6f6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wq_worker_tick / wq_worker_tick
* Struck through repros no longer work on HEAD.