FAULT_INJECTION: forcing a failure.
name fail_usercopy, interval 1, probability 0, space 0, times 0
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.4.2904/18831 is trying to acquire lock:
ffffffff8e0d1440 (console_owner){-.-.}-{0:0}, at: console_lock_spinning_enable+0x61/0x80 kernel/printk/printk.c:1897
but task is already holding lock:
ffff8880b863a358 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:646 [inline]
ffff8880b863a358 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x7e/0x130 kernel/sched/core.c:631
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #4 (&rq->__lock){-.-.}-{2:2}:
_raw_spin_lock_nested+0x31/0x40 kernel/locking/spinlock.c:378
raw_spin_rq_lock_nested+0x29/0x130 kernel/sched/core.c:638
raw_spin_rq_lock kernel/sched/sched.h:1546 [inline]
task_rq_lock+0xcf/0x490 kernel/sched/core.c:738
cgroup_move_task+0x81/0x2a0 kernel/sched/psi.c:1170
css_set_move_task+0x288/0x5f0 kernel/cgroup/cgroup.c:951
cgroup_post_fork+0x201/0x9d0 kernel/cgroup/cgroup.c:6913
copy_process+0x602d/0x76a0 kernel/fork.c:2425
kernel_clone+0xfc/0x930 kernel/fork.c:2609
user_mode_thread+0xc8/0x110 kernel/fork.c:2685
rest_init+0x23/0x2b0 init/main.c:722
start_kernel+0x3f3/0x4e0 init/main.c:1111
x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:310
x86_64_start_kernel+0x130/0x190 arch/x86/kernel/head64.c:291
common_startup_64+0x13e/0x148
-> #3 (&p->pi_lock){-.-.}-{2:2}:
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162
class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:557 [inline]
try_to_wake_up+0xb7/0x1870 kernel/sched/core.c:4181
__wake_up_common+0x135/0x1f0 kernel/sched/wait.c:108
__wake_up_common_lock kernel/sched/wait.c:125 [inline]
__wake_up+0x31/0x60 kernel/sched/wait.c:146
tty_port_default_wakeup+0x2a/0x40 drivers/tty/tty_port.c:69
serial8250_tx_chars+0x68e/0x860 drivers/tty/serial/8250/8250_port.c:1728
serial8250_handle_irq+0x761/0xcb0 drivers/tty/serial/8250/8250_port.c:1836
serial8250_default_handle_irq+0x9a/0x250 drivers/tty/serial/8250/8250_port.c:1856
serial8250_interrupt+0xf5/0x1b0 drivers/tty/serial/8250/8250_core.c:82
__handle_irq_event_percpu+0x236/0x920 kernel/irq/handle.c:203
handle_irq_event_percpu kernel/irq/handle.c:240 [inline]
handle_irq_event+0xab/0x1e0 kernel/irq/handle.c:257
handle_edge_irq+0x3ca/0x9e0 kernel/irq/chip.c:855
generic_handle_irq_desc include/linux/irqdesc.h:173 [inline]
handle_irq arch/x86/kernel/irq.c:254 [inline]
call_irq_handler arch/x86/kernel/irq.c:310 [inline]
__common_interrupt+0xd0/0x2f0 arch/x86/kernel/irq.c:325
common_interrupt+0xba/0xe0 arch/x86/kernel/irq.c:318
asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline]
_raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:194
debug_object_activate+0x2ec/0x4c0 lib/debugobjects.c:836
debug_rcu_head_queue kernel/rcu/rcu.h:236 [inline]
__call_rcu_common.constprop.0+0x35/0xa10 kernel/rcu/tree.c:3108
slab_free_hook mm/slub.c:2478 [inline]
slab_free mm/slub.c:6566 [inline]
kmem_cache_free+0x171/0x6c0 mm/slub.c:6676
exit_mmap+0x50a/0xb90 mm/mmap.c:1305
__mmput+0x12a/0x410 kernel/fork.c:1133
mmput+0x62/0x70 kernel/fork.c:1156
exit_mm kernel/exit.c:582 [inline]
do_exit+0x7c7/0x2bf0 kernel/exit.c:954
do_group_exit+0xd3/0x2a0 kernel/exit.c:1107
__do_sys_exit_group kernel/exit.c:1118 [inline]
__se_sys_exit_group kernel/exit.c:1116 [inline]
__x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1116
x64_sys_call+0x150b/0x1730 arch/x86/include/generated/asm/syscalls_64.h:232
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0x4e0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #2 (&tty->write_wait){-.-.}-{3:3}:
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162
__wake_up_common_lock kernel/sched/wait.c:124 [inline]
__wake_up+0x1c/0x60 kernel/sched/wait.c:146
tty_port_default_wakeup+0x2a/0x40 drivers/tty/tty_port.c:69
serial8250_tx_chars+0x68e/0x860 drivers/tty/serial/8250/8250_port.c:1728
serial8250_handle_irq+0x761/0xcb0 drivers/tty/serial/8250/8250_port.c:1836
serial8250_default_handle_irq+0x9a/0x250 drivers/tty/serial/8250/8250_port.c:1856
serial8250_interrupt+0xf5/0x1b0 drivers/tty/serial/8250/8250_core.c:82
__handle_irq_event_percpu+0x236/0x920 kernel/irq/handle.c:203
handle_irq_event_percpu kernel/irq/handle.c:240 [inline]
handle_irq_event+0xab/0x1e0 kernel/irq/handle.c:257
handle_edge_irq+0x3ca/0x9e0 kernel/irq/chip.c:855
generic_handle_irq_desc include/linux/irqdesc.h:173 [inline]
handle_irq arch/x86/kernel/irq.c:254 [inline]
call_irq_handler arch/x86/kernel/irq.c:310 [inline]
__common_interrupt+0xd0/0x2f0 arch/x86/kernel/irq.c:325
common_interrupt+0xba/0xe0 arch/x86/kernel/irq.c:318
asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline]
_raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:194
spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
uart_port_unlock_irqrestore include/linux/serial_core.h:788 [inline]
uart_port_unlock_deref drivers/tty/serial/serial_core.c:91 [inline]
uart_port_unlock_deref drivers/tty/serial/serial_core.c:88 [inline]
uart_write+0x2a4/0xb30 drivers/tty/serial/serial_core.c:637
process_output_block drivers/tty/n_tty.c:561 [inline]
n_tty_write+0x41b/0x11e0 drivers/tty/n_tty.c:2377
iterate_tty_write drivers/tty/tty_io.c:1006 [inline]
file_tty_write.constprop.0+0x503/0x9b0 drivers/tty/tty_io.c:1081
tty_write drivers/tty/tty_io.c:1102 [inline]
redirected_tty_write drivers/tty/tty_io.c:1125 [inline]
redirected_tty_write+0xd4/0x150 drivers/tty/tty_io.c:1105
new_sync_write fs/read_write.c:593 [inline]
vfs_write+0x7d3/0x11d0 fs/read_write.c:686
ksys_write+0x12a/0x250 fs/read_write.c:738
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0x4e0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #1 (&port_lock_key){-.-.}-{3:3}:
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162
uart_port_lock_irqsave include/linux/serial_core.h:717 [inline]
serial8250_console_write+0x181/0x1890 drivers/tty/serial/8250/8250_port.c:3355
console_emit_next_record kernel/printk/printk.c:3111 [inline]
console_flush_all+0x801/0xc60 kernel/printk/printk.c:3199
__console_flush_and_unlock kernel/printk/printk.c:3258 [inline]
console_unlock+0xd8/0x210 kernel/printk/printk.c:3298
vprintk_emit+0x3d7/0x680 kernel/printk/printk.c:2423
_printk+0xc7/0x100 kernel/printk/printk.c:2448
register_console+0xc2d/0x11b0 kernel/printk/printk.c:4099
univ8250_console_init+0x5f/0x90 drivers/tty/serial/8250/8250_core.c:516
console_init+0x14f/0x680 kernel/printk/printk.c:4298
start_kernel+0x29f/0x4e0 init/main.c:1048
x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:310
x86_64_start_kernel+0x130/0x190 arch/x86/kernel/head64.c:291
common_startup_64+0x13e/0x148
-> #0 (console_owner){-.-.}-{0:0}:
check_prev_add kernel/locking/lockdep.c:3165 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain kernel/locking/lockdep.c:3908 [inline]
__lock_acquire+0x12a6/0x1ce0 kernel/locking/lockdep.c:5237
lock_acquire kernel/locking/lockdep.c:5868 [inline]
lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5825
console_lock_spinning_enable+0x72/0x80 kernel/printk/printk.c:1897
console_emit_next_record kernel/printk/printk.c:3105 [inline]
console_flush_all+0x7aa/0xc60 kernel/printk/printk.c:3199
__console_flush_and_unlock kernel/printk/printk.c:3258 [inline]
console_unlock+0xd8/0x210 kernel/printk/printk.c:3298
vprintk_emit+0x3d7/0x680 kernel/printk/printk.c:2423
_printk+0xc7/0x100 kernel/printk/printk.c:2448
fail_dump lib/fault-inject.c:66 [inline]
should_fail_ex+0x4e7/0x640 lib/fault-inject.c:174
strncpy_from_user+0x3b/0x2e0 lib/strncpy_from_user.c:118
strncpy_from_user_nofault+0x7f/0x180 mm/maccess.c:192
bpf_trace_copy_string kernel/bpf/helpers.c:764 [inline]
bpf_bprintf_prepare+0xe90/0x13f0 kernel/bpf/helpers.c:976
____bpf_trace_printk kernel/trace/bpf_trace.c:372 [inline]
bpf_trace_printk+0xda/0x190 kernel/trace/bpf_trace.c:362
bpf_prog_930ede9872f2967c+0x3e/0x44
bpf_dispatcher_nop_func include/linux/bpf.h:1350 [inline]
__bpf_prog_run include/linux/filter.h:721 [inline]
bpf_prog_run include/linux/filter.h:728 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:2075 [inline]
bpf_trace_run2+0x236/0x590 kernel/trace/bpf_trace.c:2116
__bpf_trace_contention_begin+0xc9/0x110 include/trace/events/lock.h:95
__preempt_count_dec_and_test arch/x86/include/asm/preempt.h:95 [inline]
class_preempt_notrace_destructor include/linux/preempt.h:471 [inline]
__do_trace_contention_begin include/trace/events/lock.h:95 [inline]
trace_contention_begin.constprop.0+0xde/0x160 include/trace/events/lock.h:95
__pv_queued_spin_lock_slowpath+0x109/0xcf0 kernel/locking/qspinlock.c:219
pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:557 [inline]
queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:51 [inline]
queued_spin_lock include/asm-generic/qspinlock.h:114 [inline]
do_raw_spin_lock+0x20e/0x2b0 kernel/locking/spinlock_debug.c:116
raw_spin_rq_lock_nested kernel/sched/core.c:646 [inline]
raw_spin_rq_lock_nested+0x7e/0x130 kernel/sched/core.c:631
raw_spin_rq_lock kernel/sched/sched.h:1546 [inline]
rq_lock kernel/sched/sched.h:1868 [inline]
__schedule+0x307/0x5de0 kernel/sched/core.c:6833
preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7256
irqentry_exit+0x36/0x90 kernel/entry/common.c:211
asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:707
__inb arch/x86/include/asm/shared/io.h:22 [inline]
c6xdigio_chk_status drivers/comedi/drivers/c6xdigio.c:53 [inline]
c6xdigio_write_data.isra.0+0xbb/0x110 drivers/comedi/drivers/c6xdigio.c:66
c6xdigio_get_encoder_bits drivers/comedi/drivers/c6xdigio.c:82 [inline]
c6xdigio_encoder_read drivers/comedi/drivers/c6xdigio.c:119 [inline]
c6xdigio_encoder_insn_read+0x159/0x470 drivers/comedi/drivers/c6xdigio.c:201
parse_insn+0xf49/0x1970 drivers/comedi/comedi_fops.c:1454
do_insn_ioctl+0x152/0x4e0 drivers/comedi/comedi_fops.c:1679
comedi_unlocked_ioctl+0x1618/0x2f00 drivers/comedi/comedi_fops.c:2308
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl fs/ioctl.c:583 [inline]
__x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0x4e0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
other info that might help us debug this:
Chain exists of:
console_owner --> &p->pi_lock --> &rq->__lock
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&rq->__lock);
lock(&p->pi_lock);
lock(&rq->__lock);
lock(console_owner);
*** DEADLOCK ***
5 locks held by syz.4.2904/18831:
#0: ffff88814c9498f8 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_unlocked_ioctl+0x167/0x2f00 drivers/comedi/comedi_fops.c:2166
#1: ffff8880b863a358 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:646 [inline]
#1: ffff8880b863a358 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x7e/0x130 kernel/sched/core.c:631
#2: ffffffff8e1c4120 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#2: ffffffff8e1c4120 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#2: ffffffff8e1c4120 (rcu_read_lock){....}-{1:3}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2074 [inline]
#2: ffffffff8e1c4120 (rcu_read_lock){....}-{1:3}, at: bpf_trace_run2+0x1bc/0x590 kernel/trace/bpf_trace.c:2116
#3: ffffffff8e1b1880 (console_lock){+.+.}-{0:0}, at: _printk+0xc7/0x100 kernel/printk/printk.c:2448
#4: ffffffff8e1b18f0 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:336 [inline]
#4: ffffffff8e1b18f0 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:319 [inline]
#4: ffffffff8e1b18f0 (console_srcu){....}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:289 [inline]
#4: ffffffff8e1b18f0 (console_srcu){....}-{0:0}, at: console_flush_all+0x158/0xc60 kernel/printk/printk.c:3176
stack backtrace:
CPU: 1 UID: 0 PID: 18831 Comm: syz.4.2904 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
print_circular_bug+0x275/0x350 kernel/locking/lockdep.c:2043
check_noncircular+0x14c/0x170 kernel/locking/lockdep.c:2175
check_prev_add kernel/locking/lockdep.c:3165 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain kernel/locking/lockdep.c:3908 [inline]
__lock_acquire+0x12a6/0x1ce0 kernel/locking/lockdep.c:5237
lock_acquire kernel/locking/lockdep.c:5868 [inline]
lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5825
console_lock_spinning_enable+0x72/0x80 kernel/printk/printk.c:1897
console_emit_next_record kernel/printk/printk.c:3105 [inline]
console_flush_all+0x7aa/0xc60 kernel/printk/printk.c:3199
__console_flush_and_unlock kernel/printk/printk.c:3258 [inline]
console_unlock+0xd8/0x210 kernel/printk/printk.c:3298
vprintk_emit+0x3d7/0x680 kernel/printk/printk.c:2423
_printk+0xc7/0x100 kernel/printk/printk.c:2448
fail_dump lib/fault-inject.c:66 [inline]
should_fail_ex+0x4e7/0x640 lib/fault-inject.c:174
strncpy_from_user+0x3b/0x2e0 lib/strncpy_from_user.c:118
strncpy_from_user_nofault+0x7f/0x180 mm/maccess.c:192
bpf_trace_copy_string kernel/bpf/helpers.c:764 [inline]
bpf_bprintf_prepare+0xe90/0x13f0 kernel/bpf/helpers.c:976
____bpf_trace_printk kernel/trace/bpf_trace.c:372 [inline]
bpf_trace_printk+0xda/0x190 kernel/trace/bpf_trace.c:362
bpf_prog_930ede9872f2967c+0x3e/0x44
bpf_dispatcher_nop_func include/linux/bpf.h:1350 [inline]
__bpf_prog_run include/linux/filter.h:721 [inline]
bpf_prog_run include/linux/filter.h:728 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:2075 [inline]
bpf_trace_run2+0x236/0x590 kernel/trace/bpf_trace.c:2116
__bpf_trace_contention_begin+0xc9/0x110 include/trace/events/lock.h:95
__preempt_count_dec_and_test arch/x86/include/asm/preempt.h:95 [inline]
class_preempt_notrace_destructor include/linux/preempt.h:471 [inline]
__do_trace_contention_begin include/trace/events/lock.h:95 [inline]
trace_contention_begin.constprop.0+0xde/0x160 include/trace/events/lock.h:95
__pv_queued_spin_lock_slowpath+0x109/0xcf0 kernel/locking/qspinlock.c:219
pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:557 [inline]
queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:51 [inline]
queued_spin_lock include/asm-generic/qspinlock.h:114 [inline]
do_raw_spin_lock+0x20e/0x2b0 kernel/locking/spinlock_debug.c:116
raw_spin_rq_lock_nested kernel/sched/core.c:646 [inline]
raw_spin_rq_lock_nested+0x7e/0x130 kernel/sched/core.c:631
raw_spin_rq_lock kernel/sched/sched.h:1546 [inline]
rq_lock kernel/sched/sched.h:1868 [inline]
__schedule+0x307/0x5de0 kernel/sched/core.c:6833
preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7256
irqentry_exit+0x36/0x90 kernel/entry/common.c:211
asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:707
RIP: 0010:c6xdigio_chk_status drivers/comedi/drivers/c6xdigio.c:54 [inline]
RIP: 0010:c6xdigio_write_data.isra.0+0xbb/0x110 drivers/comedi/drivers/c6xdigio.c:66
Code: 31 ed 41 83 c5 01 eb 19 e8 d2 15 fb f8 83 c5 01 bf 14 00 00 00 89 ee e8 03 11 fb f8 83 fd 14 74 20 e8 b9 15 fb f8 44 89 ea ec <89> c3 44 89 e6 81 e3 80 00 00 00 89 df e8 23 10 fb f8 44 39 e3 74
RSP: 0018:ffffc9001d507a90 EFLAGS: 00000293
RAX: 00000000000000e9 RBX: 0000000000000080 RCX: ffffffff88c01eed
RDX: 0000000000000402 RSI: ffffffff88c01ef7 RDI: 0000000000000005
RBP: 0000000000000001 R08: 0000000000000005 R09: 0000000000000014
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000080
R13: 0000000000000402 R14: 0000000000000050 R15: 000000000000002e
c6xdigio_get_encoder_bits drivers/comedi/drivers/c6xdigio.c:82 [inline]
c6xdigio_encoder_read drivers/comedi/drivers/c6xdigio.c:119 [inline]
c6xdigio_encoder_insn_read+0x159/0x470 drivers/comedi/drivers/c6xdigio.c:201
parse_insn+0xf49/0x1970 drivers/comedi/comedi_fops.c:1454
do_insn_ioctl+0x152/0x4e0 drivers/comedi/comedi_fops.c:1679
comedi_unlocked_ioctl+0x1618/0x2f00 drivers/comedi/comedi_fops.c:2308
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl fs/ioctl.c:583 [inline]
__x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0x4e0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4dcb58eec9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f4dcc3b6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f4dcb7e5fa0 RCX: 00007f4dcb58eec9
RDX: 0000200000000000 RSI: 000000008028640c RDI: 0000000000000003
RBP: 00007f4dcc3b6090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007f4dcb7e6038 R14: 00007f4dcb7e5fa0 R15: 00007ffdebf1b4a8
CPU: 1 UID: 0 PID: 18831 Comm: syz.4.2904 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
fail_dump lib/fault-inject.c:73 [inline]
should_fail_ex+0x512/0x640 lib/fault-inject.c:174
strncpy_from_user+0x3b/0x2e0 lib/strncpy_from_user.c:118
strncpy_from_user_nofault+0x7f/0x180 mm/maccess.c:192
bpf_trace_copy_string kernel/bpf/helpers.c:764 [inline]
bpf_bprintf_prepare+0xe90/0x13f0 kernel/bpf/helpers.c:976
____bpf_trace_printk kernel/trace/bpf_trace.c:372 [inline]
bpf_trace_printk+0xda/0x190 kernel/trace/bpf_trace.c:362
bpf_prog_930ede9872f2967c+0x3e/0x44
bpf_dispatcher_nop_func include/linux/bpf.h:1350 [inline]
__bpf_prog_run include/linux/filter.h:721 [inline]
bpf_prog_run include/linux/filter.h:728 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:2075 [inline]
bpf_trace_run2+0x236/0x590 kernel/trace/bpf_trace.c:2116
__bpf_trace_contention_begin+0xc9/0x110 include/trace/events/lock.h:95
__preempt_count_dec_and_test arch/x86/include/asm/preempt.h:95 [inline]
class_preempt_notrace_destructor include/linux/preempt.h:471 [inline]
__do_trace_contention_begin include/trace/events/lock.h:95 [inline]
trace_contention_begin.constprop.0+0xde/0x160 include/trace/events/lock.h:95
__pv_queued_spin_lock_slowpath+0x109/0xcf0 kernel/locking/qspinlock.c:219
pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:557 [inline]
queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:51 [inline]
queued_spin_lock include/asm-generic/qspinlock.h:114 [inline]
do_raw_spin_lock+0x20e/0x2b0 kernel/locking/spinlock_debug.c:116
raw_spin_rq_lock_nested kernel/sched/core.c:646 [inline]
raw_spin_rq_lock_nested+0x7e/0x130 kernel/sched/core.c:631
raw_spin_rq_lock kernel/sched/sched.h:1546 [inline]
rq_lock kernel/sched/sched.h:1868 [inline]
__schedule+0x307/0x5de0 kernel/sched/core.c:6833
preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7256
irqentry_exit+0x36/0x90 kernel/entry/common.c:211
asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:707
RIP: 0010:c6xdigio_chk_status drivers/comedi/drivers/c6xdigio.c:54 [inline]
RIP: 0010:c6xdigio_write_data.isra.0+0xbb/0x110 drivers/comedi/drivers/c6xdigio.c:66
Code: 31 ed 41 83 c5 01 eb 19 e8 d2 15 fb f8 83 c5 01 bf 14 00 00 00 89 ee e8 03 11 fb f8 83 fd 14 74 20 e8 b9 15 fb f8 44 89 ea ec <89> c3 44 89 e6 81 e3 80 00 00 00 89 df e8 23 10 fb f8 44 39 e3 74
RSP: 0018:ffffc9001d507a90 EFLAGS: 00000293
RAX: 00000000000000e9 RBX: 0000000000000080 RCX: ffffffff88c01eed
RDX: 0000000000000402 RSI: ffffffff88c01ef7 RDI: 0000000000000005
RBP: 0000000000000001 R08: 0000000000000005 R09: 0000000000000014
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000080
R13: 0000000000000402 R14: 0000000000000050 R15: 000000000000002e
c6xdigio_get_encoder_bits drivers/comedi/drivers/c6xdigio.c:82 [inline]
c6xdigio_encoder_read drivers/comedi/drivers/c6xdigio.c:119 [inline]
c6xdigio_encoder_insn_read+0x159/0x470 drivers/comedi/drivers/c6xdigio.c:201
parse_insn+0xf49/0x1970 drivers/comedi/comedi_fops.c:1454
do_insn_ioctl+0x152/0x4e0 drivers/comedi/comedi_fops.c:1679
comedi_unlocked_ioctl+0x1618/0x2f00 drivers/comedi/comedi_fops.c:2308
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl fs/ioctl.c:583 [inline]
__x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0x4e0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4dcb58eec9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f4dcc3b6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f4dcb7e5fa0 RCX: 00007f4dcb58eec9
RDX: 0000200000000000 RSI: 000000008028640c RDI: 0000000000000003
RBP: 00007f4dcc3b6090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007f4dcb7e6038 R14: 00007f4dcb7e5fa0 R15: 00007ffdebf1b4a8
----------------
Code disassembly (best guess):
0: 31 ed xor %ebp,%ebp
2: 41 83 c5 01 add $0x1,%r13d
6: eb 19 jmp 0x21
8: e8 d2 15 fb f8 call 0xf8fb15df
d: 83 c5 01 add $0x1,%ebp
10: bf 14 00 00 00 mov $0x14,%edi
15: 89 ee mov %ebp,%esi
17: e8 03 11 fb f8 call 0xf8fb111f
1c: 83 fd 14 cmp $0x14,%ebp
1f: 74 20 je 0x41
21: e8 b9 15 fb f8 call 0xf8fb15df
26: 44 89 ea mov %r13d,%edx
29: ec in (%dx),%al
* 2a: 89 c3 mov %eax,%ebx <-- trapping instruction
2c: 44 89 e6 mov %r12d,%esi
2f: 81 e3 80 00 00 00 and $0x80,%ebx
35: 89 df mov %ebx,%edi
37: e8 23 10 fb f8 call 0xf8fb105f
3c: 44 39 e3 cmp %r12d,%ebx
3f: 74 .byte 0x74