KCSAN: data-race in __ps2_command / ps2_interrupt

Status: moderation: reported on 2026/07/24 21:38
Subsystems: input
Labels: race:benign prio:high
[Documentation on labels]
Reported-by: syzbot+1ecceabfed79f6a96c7d@syzkaller.appspotmail.com
First crash: 49d, last: 2d06h
✨ AI Jobs (2)
ID Workflow Result Correct Bug Created Started Finished Revision
a48e11bb assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ✅ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ✅ KCSAN: data-race in __ps2_command / ps2_interrupt 2026/07/26 02:33 2026/07/26 02:33 2026/07/26 02:37 492bab15
f7b71f5b assessment-kcsan Benign: ✅ KCSAN: data-race in __ps2_command / ps2_interrupt 2026/07/24 21:38 2026/07/24 21:38 2026/07/24 22:08 1bdb5c57

Sample crash report:
==================================================================
BUG: KCSAN: data-race in __ps2_command / ps2_interrupt

write to 0xffff888103a5a658 of 1 bytes by interrupt on cpu 0:
 ps2_handle_response drivers/input/serio/libps2.c:479 [inline]
 ps2_interrupt+0x1be/0x550 drivers/input/serio/libps2.c:608
 serio_interrupt+0x66/0xf0 drivers/input/serio/serio.c:967
 i8042_handle_data+0x388/0x680 drivers/input/serio/i8042.c:598
 i8042_interrupt+0x15/0x90 drivers/input/serio/i8042.c:605
 __handle_irq_event_percpu+0x8b/0x480 kernel/irq/handle.c:209
 handle_irq_event_percpu kernel/irq/handle.c:246 [inline]
 handle_irq_event+0x64/0xf0 kernel/irq/handle.c:263
 handle_edge_irq+0x155/0x440 kernel/irq/chip.c:859
 generic_handle_irq_desc include/linux/irqdesc.h:188 [inline]
 handle_irq arch/x86/kernel/irq.c:209 [inline]
 call_irq_handler arch/x86/kernel/irq.c:-1 [inline]
 __common_interrupt+0x60/0xb0 arch/x86/kernel/irq.c:280
 common_interrupt+0x7e/0x90 arch/x86/kernel/irq.c:273
 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:665
 __preempt_count_dec_and_test arch/x86/include/asm/preempt.h:123 [inline]
 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:220 [inline]
 _raw_spin_unlock_irq+0x12/0x30 kernel/locking/spinlock.c:229
 process_one_work kernel/workqueue.c:3362 [inline]
 process_scheduled_works+0x4f6/0xa50 kernel/workqueue.c:3479
 worker_thread+0x569/0x750 kernel/workqueue.c:3560
 kthread+0x223/0x270 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 to 0xffff888103a5a658 of 1 bytes by task 3399 on cpu 1:
 __ps2_command+0x591/0xaa0 drivers/input/serio/libps2.c:343
 ps2_command+0x52/0x90 drivers/input/serio/libps2.c:403
 ps2pp_detect+0xa2/0x940 drivers/input/mouse/logips2pp.c:372
 psmouse_do_detect drivers/input/mouse/psmouse-base.c:995 [inline]
 psmouse_try_protocol+0x25e/0x310 drivers/input/mouse/psmouse-base.c:1009
 psmouse_extensions+0x7ec/0x960 drivers/input/mouse/psmouse-base.c:1162
 __psmouse_reconnect+0x3dd/0x880 drivers/input/mouse/psmouse-base.c:1685
 psmouse_reconnect+0x23/0x40 drivers/input/mouse/psmouse-base.c:1723
 serio_reconnect_driver drivers/input/serio/serio.c:52 [inline]
 serio_reconnect_port drivers/input/serio/serio.c:558 [inline]
 serio_handle_event+0x1c7/0xac0 drivers/input/serio/serio.c:201
 process_one_work kernel/workqueue.c:3396 [inline]
 process_scheduled_works+0x56a/0xa50 kernel/workqueue.c:3479
 worker_thread+0x569/0x750 kernel/workqueue.c:3560
 kthread+0x223/0x270 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: 0x02 -> 0x01

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3399 Comm: kworker/1:5 Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: events_long serio_handle_event
==================================================================

Crashes (7):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/10 02:26 upstream 50d05c7c76c9 4e8b1cc6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __ps2_command / ps2_interrupt
2026/09/01 05:48 upstream bf1079577a11 316d9396 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __ps2_command / ps2_interrupt
2026/08/25 09:02 upstream 66498c75b4f8 614e416a .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __ps2_command / ps2_interrupt
2026/08/05 07:11 upstream c21bb4193868 52aa2820 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __ps2_command / ps2_interrupt
2026/07/27 03:01 upstream 4235cb24ec1e 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __ps2_command / ps2_interrupt
2026/07/24 21:38 upstream 48a5a7ab8d6a dd737a83 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __ps2_command / ps2_interrupt
2026/07/24 21:38 upstream 48a5a7ab8d6a dd737a83 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __ps2_command / ps2_interrupt
* Struck through repros no longer work on HEAD.