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BUG: KCSAN: data-race in ps2_do_sendbyte / ps2_interrupt

write to 0xffff888103807c48 of 8 bytes by interrupt on cpu 0:
 ps2_interrupt+0x50d/0x550 drivers/input/serio/libps2.c:-1
 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+0x3e/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_irqrestore include/linux/spinlock_api_smp.h:211 [inline]
 _raw_spin_unlock_irqrestore+0x1a/0x30 kernel/locking/spinlock.c:221
 __mod_timer+0x6ff/0x990 kernel/time/timer.c:1139
 mod_timer+0x1f/0x30 kernel/time/timer.c:1195
 mrp_join_timer_arm net/802/mrp.c:597 [inline]
 mrp_join_timer+0x3db/0x400 net/802/mrp.c:612
 call_timer_fn+0x36/0x250 kernel/time/timer.c:1748
 expire_timers kernel/time/timer.c:1799 [inline]
 __run_timers kernel/time/timer.c:2374 [inline]
 __run_timer_base+0x40c/0x5f0 kernel/time/timer.c:2386
 run_timer_base kernel/time/timer.c:2395 [inline]
 run_timer_softirq+0x31/0x70 kernel/time/timer.c:2405
 handle_softirqs+0xcc/0x2a0 kernel/softirq.c:645
 __do_softirq kernel/softirq.c:679 [inline]
 invoke_softirq kernel/softirq.c:519 [inline]
 __irq_exit_rcu+0x44/0xe0 kernel/softirq.c:758
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
 sysvec_apic_timer_interrupt+0x74/0x80 arch/x86/kernel/apic/apic.c:1062
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
 __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
 spin_unlock_irq include/linux/spinlock.h:413 [inline]
 shmem_add_to_page_cache+0x3e6/0x5b0 mm/shmem.c:939
 shmem_alloc_and_add_folio mm/shmem.c:2004 [inline]
 shmem_get_folio_gfp+0x517/0xd90 mm/shmem.c:2531
 shmem_fault+0xf6/0x250 mm/shmem.c:2732
 __do_fault mm/memory.c:5565 [inline]
 do_read_fault mm/memory.c:6000 [inline]
 do_fault mm/memory.c:6134 [inline]
 do_pte_missing mm/memory.c:4700 [inline]
 handle_pte_fault mm/memory.c:6558 [inline]
 __handle_mm_fault mm/memory.c:6707 [inline]
 handle_mm_fault+0x2310/0x3bb0 mm/memory.c:6876
 faultin_page mm/gup.c:1126 [inline]
 __get_user_pages+0x12e9/0x1eb0 mm/gup.c:1428
 populate_vma_page_range mm/gup.c:1860 [inline]
 __mm_populate+0x242/0x390 mm/gup.c:1963
 mm_populate include/linux/mm.h:4288 [inline]
 vm_mmap_pgoff+0x23b/0x2d0 mm/util.c:586
 ksys_mmap_pgoff+0xc1/0x310 mm/mmap.c:619
 x64_sys_call+0x23b3/0x2550 arch/x86/include/generated/asm/syscalls_64.h:10
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x112/0x360 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888103807c48 of 8 bytes by task 17624 on cpu 1:
 ps2_do_sendbyte+0x17e/0x320 drivers/input/serio/libps2.c:65
 __ps2_command+0x364/0xaa0 drivers/input/serio/libps2.c:322
 ps2_command+0x52/0x90 drivers/input/serio/libps2.c:403
 synaptics_detect+0x5e/0x130 drivers/input/mouse/synaptics.c:102
 psmouse_do_detect drivers/input/mouse/psmouse-base.c:995 [inline]
 psmouse_extensions+0x4df/0x960 drivers/input/mouse/psmouse-base.c:1090
 __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_reconnect_subtree drivers/input/serio/serio.c:578 [inline]
 drvctl_store+0x2ac/0xc20 drivers/input/serio/serio.c:364
 dev_attr_store+0x4a/0x70 drivers/base/core.c:2509
 sysfs_kf_write+0xfe/0x120 fs/sysfs/file.c:145
 kernfs_fop_write_iter+0x1d2/0x2e0 fs/kernfs/file.c:345
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x57f/0x9a0 fs/read_write.c:687
 ksys_write+0xdc/0x1a0 fs/read_write.c:739
 __do_sys_write fs/read_write.c:750 [inline]
 __se_sys_write fs/read_write.c:747 [inline]
 __x64_sys_write+0x40/0x50 fs/read_write.c:747
 x64_sys_call+0x154e/0x2550 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x112/0x360 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000000000001 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 17624 Comm: syz.8.6041 Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
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input: ImExPS/2 Generic Explorer Mouse as /devices/platform/i8042/serio1/input/input19