================================ WARNING: inconsistent lock state syzkaller #0 Tainted: G L -------------------------------- inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-W} usage. syz.7.5980/16899 [HC1[1]:SC1[1]:HE0:SE0] takes: ffff888032429868 (&dev->spinlock){?...}-{3:3}, at: spin_lock include/linux/spinlock.h:341 [inline] ffff888032429868 (&dev->spinlock){?...}-{3:3}, at: das16m1_interrupt+0x5e/0x180 drivers/comedi/drivers/das16m1.c:460 {HARDIRQ-ON-W} state was registered at: lock_acquire+0xf0/0x2e0 kernel/locking/lockdep.c:5868 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:150 [inline] _raw_spin_lock_bh+0x36/0x50 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:347 [inline] waveform_ao_cancel+0x8d/0x120 drivers/comedi/drivers/comedi_test.c:628 do_cancel drivers/comedi/comedi_fops.c:818 [inline] comedi_close+0x27e/0x5e0 drivers/comedi/comedi_fops.c:3036 __fput+0x44f/0xa70 fs/file_table.c:469 task_work_run+0x1d9/0x270 kernel/task_work.c:233 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] __exit_to_user_mode_loop kernel/entry/common.c:67 [inline] exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline] do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f irq event stamp: 1681 hardirqs last enabled at (1680): [] handle_softirqs+0x158/0x870 kernel/softirq.c:610 hardirqs last disabled at (1681): [] common_interrupt+0x13/0xe0 arch/x86/kernel/irq.c:326 softirqs last enabled at (1664): [] __do_softirq kernel/softirq.c:660 [inline] softirqs last enabled at (1664): [] invoke_softirq kernel/softirq.c:496 [inline] softirqs last enabled at (1664): [] __irq_exit_rcu+0x5f/0x150 kernel/softirq.c:727 softirqs last disabled at (1679): [] __do_softirq kernel/softirq.c:660 [inline] softirqs last disabled at (1679): [] invoke_softirq kernel/softirq.c:496 [inline] softirqs last disabled at (1679): [] __irq_exit_rcu+0x5f/0x150 kernel/softirq.c:727 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&dev->spinlock); lock(&dev->spinlock); *** DEADLOCK *** 2 locks held by syz.7.5980/16899: #0: ffff88807fa392e8 (&tty->termios_rwsem){++++}-{4:4}, at: class_rwsem_write_constructor include/linux/rwsem.h:270 [inline] #0: ffff88807fa392e8 (&tty->termios_rwsem){++++}-{4:4}, at: uart_ioctl+0x109/0x1af0 drivers/tty/serial/serial_core.c:1561 #1: ffff8881412a0e90 (&port->mutex){+.+.}-{4:4}, at: class_mutex_intr_constructor include/linux/mutex.h:255 [inline] #1: ffff8881412a0e90 (&port->mutex){+.+.}-{4:4}, at: uart_do_autoconfig drivers/tty/serial/serial_core.c:1145 [inline] #1: ffff8881412a0e90 (&port->mutex){+.+.}-{4:4}, at: uart_ioctl+0x133/0x1af0 drivers/tty/serial/serial_core.c:1562 stack backtrace: CPU: 0 UID: 0 PID: 16899 Comm: syz.7.5980 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_usage_bug+0x28b/0x2e0 kernel/locking/lockdep.c:4042 valid_state kernel/locking/lockdep.c:4056 [inline] mark_lock_irq+0x410/0x420 kernel/locking/lockdep.c:-1 mark_lock+0x115/0x190 kernel/locking/lockdep.c:4753 mark_usage kernel/locking/lockdep.c:4639 [inline] __lock_acquire+0x661/0x2cf0 kernel/locking/lockdep.c:5191 lock_acquire+0xf0/0x2e0 kernel/locking/lockdep.c:5868 __raw_spin_lock include/linux/spinlock_api_smp.h:158 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:341 [inline] das16m1_interrupt+0x5e/0x180 drivers/comedi/drivers/das16m1.c:460 __handle_irq_event_percpu+0x227/0x9e0 kernel/irq/handle.c:209 handle_irq_event_percpu kernel/irq/handle.c:246 [inline] handle_irq_event+0x8b/0x1e0 kernel/irq/handle.c:263 handle_edge_irq+0x23b/0xa10 kernel/irq/chip.c:855 generic_handle_irq_desc include/linux/irqdesc.h:186 [inline] handle_irq arch/x86/kernel/irq.c:262 [inline] call_irq_handler arch/x86/kernel/irq.c:-1 [inline] __common_interrupt+0x141/0x1f0 arch/x86/kernel/irq.c:333 common_interrupt+0x5e/0xe0 arch/x86/kernel/irq.c:326 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:688 RIP: 0010:variable_ffs arch/x86/include/asm/bitops.h:312 [inline] RIP: 0010:handle_softirqs+0x160/0x870 kernel/softirq.c:614 Code: 89 6c 24 20 0f b7 db 48 c7 c7 80 28 cb 8b e8 d7 a7 32 0a 65 66 c7 05 45 ba b9 11 00 00 e8 48 82 45 00 fb 48 c7 c5 c0 c0 60 8e ff ff ff ff 0f bc c3 41 89 c6 41 ff c6 0f 84 30 04 00 00 89 5c RSP: 0018:ffffc90000007f38 EFLAGS: 00000216 RAX: 0000000000000690 RBX: 0000000000000100 RCX: 0000000080000101 RDX: 0000000000000002 RSI: ffffffff8e0150a1 RDI: ffffffff8c2a0b00 RBP: ffffffff8e60c0c0 R08: ffffffff9033cab7 R09: 1ffffffff2067956 R10: dffffc0000000000 R11: fffffbfff2067957 R12: 0000000000000000 R13: 0000000000000000 R14: ffff8880a5263c80 R15: 0000000000000000 __do_softirq kernel/softirq.c:660 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0x5f/0x150 kernel/softirq.c:727 irq_exit_rcu+0x9/0x30 kernel/softirq.c:743 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:179 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x47/0x80 kernel/locking/spinlock.c:194 Code: f7 e8 ed 02 e5 f5 f7 c3 00 02 00 00 74 05 e8 d0 57 10 f6 9c 58 a9 00 02 00 00 75 27 f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 34 c9 d6 f5 65 8b 05 9d 8f 84 07 85 c0 74 18 5b 41 5e e9 81 48 RSP: 0018:ffffc90003637a28 EFLAGS: 00000206 RAX: 0000000000000006 RBX: 0000000000000293 RCX: 0000000080000001 RDX: 0000000000000006 RSI: ffffffff8e0150a1 RDI: 0000000000000001 RBP: ffffc90003637be0 R08: ffffffff9033cab7 R09: 1ffffffff2067956 R10: dffffc0000000000 R11: fffffbfff2067957 R12: 0000000000000100 R13: dffffc0000000000 R14: ffffffff9a830520 R15: ffffffff8f22c720 spin_unlock_irqrestore include/linux/spinlock.h:407 [inline] uart_port_unlock_irqrestore include/linux/serial_core.h:788 [inline] autoconfig drivers/tty/serial/8250/8250_port.c:1199 [inline] serial8250_config_port+0x1467/0x5300 drivers/tty/serial/8250/8250_port.c:3083 univ8250_config_port+0x3b9/0x980 drivers/tty/serial/8250/8250_rsa.c:72 uart_do_autoconfig drivers/tty/serial/serial_core.c:1170 [inline] uart_ioctl+0x1570/0x1af0 drivers/tty/serial/serial_core.c:1562 tty_ioctl+0x928/0xde0 drivers/tty/tty_io.c:2792 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f4d91b9c629 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f4d92aa8028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f4d91e15fa0 RCX: 00007f4d91b9c629 RDX: 0000000000000000 RSI: 0000000000005453 RDI: 0000000000000003 RBP: 00007f4d91c32b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f4d91e16038 R14: 00007f4d91e15fa0 R15: 00007ffd3d3a69c8 comedi comedi3: fifo overflow ---------------- Code disassembly (best guess): 0: 89 6c 24 20 mov %ebp,0x20(%rsp) 4: 0f b7 db movzwl %bx,%ebx 7: 48 c7 c7 80 28 cb 8b mov $0xffffffff8bcb2880,%rdi e: e8 d7 a7 32 0a call 0xa32a7ea 13: 65 66 c7 05 45 ba b9 movw $0x0,%gs:0x11b9ba45(%rip) # 0x11b9ba62 1a: 11 00 00 1d: e8 48 82 45 00 call 0x45826a 22: fb sti 23: 48 c7 c5 c0 c0 60 8e mov $0xffffffff8e60c0c0,%rbp * 2a: b8 ff ff ff ff mov $0xffffffff,%eax <-- trapping instruction 2f: 0f bc c3 bsf %ebx,%eax 32: 41 89 c6 mov %eax,%r14d 35: 41 ff c6 inc %r14d 38: 0f 84 30 04 00 00 je 0x46e 3e: 89 .byte 0x89 3f: 5c pop %rsp