------------[ cut here ]------------
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.0.1760/12837 is trying to acquire lock:
ffffffff8e2d1820 (console_owner){-.-.}-{0:0}, at: console_lock_spinning_enable+0x61/0x80 kernel/printk/printk.c:1897
but task is already holding lock:
ffff8880b843a4d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:646 [inline]
ffff8880b843a4d8 (&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:1547 [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+0x3f6/0x4e0 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
pty_close+0x226/0x4f0 drivers/tty/pty.c:68
tty_release+0x3af/0x1430 drivers/tty/tty_io.c:1745
__fput+0x402/0xb70 fs/file_table.c:468
task_work_run+0x150/0x240 kernel/task_work.c:227
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
exit_to_user_mode_loop+0xec/0x130 kernel/entry/common.c:43
exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
do_syscall_64+0x426/0xfa0 arch/x86/entry/syscall_64.c:100
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+0x47/0x60 drivers/tty/tty_port.c:67
serial8250_tx_chars+0x68e/0x860 drivers/tty/serial/8250/8250_port.c:1719
__start_tx+0x3df/0x490 drivers/tty/serial/8250/8250_port.c:1426
serial8250_start_tx+0x368/0x530 drivers/tty/serial/8250/8250_port.c:1535
__uart_start+0x295/0x500 drivers/tty/serial/serial_core.c:161
uart_write+0x218/0xb30 drivers/tty/serial/serial_core.c:633
process_output_block drivers/tty/n_tty.c:561 [inline]
n_tty_write+0x41e/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/0xfa0 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:3301
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:511
console_init+0x152/0x680 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+0x126f/0x1c90 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
__report_bug lib/bug.c:191 [inline]
report_bug+0x435/0x580 lib/bug.c:215
handle_bug+0x184/0x210 arch/x86/kernel/traps.c:338
exc_invalid_op+0x17/0x50 arch/x86/kernel/traps.c:392
asm_exc_invalid_op+0x1a/0x20 arch/x86/include/asm/idtentry.h:616
lockdep_assert_rq_held kernel/sched/sched.h:1538 [inline]
lockdep_assert_rq_held kernel/sched/sched.h:1536 [inline]
update_rq_clock+0x34a/0xc70 kernel/sched/core.c:836
pick_next_task kernel/sched/core.c:6158 [inline]
__schedule+0x27fc/0x5de0 kernel/sched/core.c:6870
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:702
queue_work_on+0x86/0x1f0 kernel/workqueue.c:2385
queue_work include/linux/workqueue.h:669 [inline]
snd_virmidi_output_trigger+0xf1/0x130 sound/core/seq/seq_virmidi.c:178
snd_rawmidi_output_trigger sound/core/rawmidi.c:213 [inline]
snd_rawmidi_output_trigger sound/core/rawmidi.c:209 [inline]
snd_rawmidi_kernel_write1+0x3fb/0x8a0 sound/core/rawmidi.c:1576
snd_rawmidi_write+0x26e/0xc10 sound/core/rawmidi.c:1629
vfs_write+0x2a0/0x11d0 fs/read_write.c:684
ksys_write+0x1f8/0x250 fs/read_write.c:738
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xfa0 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 ***
3 locks held by syz.0.1760/12837:
#0: ffff8880b843a4d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:646 [inline]
#0: ffff8880b843a4d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x7e/0x130 kernel/sched/core.c:631
#1: ffffffff8e3b1c60 (console_lock){+.+.}-{0:0}, at: _printk+0xc7/0x100 kernel/printk/printk.c:2448
#2: ffffffff8e3b1cd0 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:336 [inline]
#2: ffffffff8e3b1cd0 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:335 [inline]
#2: ffffffff8e3b1cd0 (console_srcu){....}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:289 [inline]
#2: ffffffff8e3b1cd0 (console_srcu){....}-{0:0}, at: console_flush_all+0x158/0xc60 kernel/printk/printk.c:3176
stack backtrace:
CPU: 0 UID: 0 PID: 12837 Comm: syz.0.1760 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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+0x126f/0x1c90 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
__report_bug lib/bug.c:191 [inline]
report_bug+0x435/0x580 lib/bug.c:215
handle_bug+0x184/0x210 arch/x86/kernel/traps.c:338
exc_invalid_op+0x17/0x50 arch/x86/kernel/traps.c:392
asm_exc_invalid_op+0x1a/0x20 arch/x86/include/asm/idtentry.h:616
RIP: 0010:lockdep_assert_rq_held kernel/sched/sched.h:1538 [inline]
RIP: 0010:lockdep_assert_rq_held kernel/sched/sched.h:1536 [inline]
RIP: 0010:update_rq_clock+0x34a/0xc70 kernel/sched/core.c:836
Code: ab 48 0b 00 00 48 83 c4 18 5b 5d 41 5c 41 5d 41 5e 41 5f e9 88 f8 d6 09 a8 04 0f 84 9c fd ff ff 90 0f 0b 90 e9 93 fd ff ff 90 <0f> 0b 90 e9 4f fd ff ff 48 8d bb 18 0e 00 00 48 b8 00 00 00 00 00
RSP: 0018:ffffc90004337800 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffff8880b853a4c0 RCX: 0000000000000001
RDX: 0000000000000000 RSI: ffffffff8da03cc9 RDI: ffffffff8bf07940
RBP: 0000000000000001 R08: 0000000000000000 R09: fffffbfff2104a7a
R10: ffffffff908253d7 R11: 0000000000000001 R12: ffffffff90828434
R13: ffff88801d2dbc80 R14: ffff8880b853a4c0 R15: ffff8880b843afc8
pick_next_task kernel/sched/core.c:6158 [inline]
__schedule+0x27fc/0x5de0 kernel/sched/core.c:6870
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:702
RIP: 0010:queue_work_on+0x86/0x1f0 kernel/workqueue.c:2397
Code: 38 00 45 84 f6 74 38 e8 48 ba 38 00 9c 5b 81 e3 00 02 00 00 31 ff 48 89 de e8 a6 b5 38 00 48 85 db 0f 85 4f 01 00 00 45 31 f6 25 ba 38 00 44 89 f0 5b 5d 41 5c 41 5d 41 5e c3 cc cc cc cc e8
RSP: 0018:ffffc90004337ae8 EFLAGS: 00000283
RAX: 000000000002885e RBX: 0000000000000000 RCX: ffffc9000be89000
RDX: 0000000000080000 RSI: ffffffff81839e26 RDI: 0000000000000007
RBP: 0000000000000200 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000008
R13: ffff88813ff15c00 R14: 0000000000000001 R15: ffff88802fe74600
queue_work include/linux/workqueue.h:669 [inline]
snd_virmidi_output_trigger+0xf1/0x130 sound/core/seq/seq_virmidi.c:178
snd_rawmidi_output_trigger sound/core/rawmidi.c:213 [inline]
snd_rawmidi_output_trigger sound/core/rawmidi.c:209 [inline]
snd_rawmidi_kernel_write1+0x3fb/0x8a0 sound/core/rawmidi.c:1576
snd_rawmidi_write+0x26e/0xc10 sound/core/rawmidi.c:1629
vfs_write+0x2a0/0x11d0 fs/read_write.c:684
ksys_write+0x1f8/0x250 fs/read_write.c:738
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ffb3258f7c9
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:00007ffb33438038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007ffb327e5fa0 RCX: 00007ffb3258f7c9
RDX: 000000100000e3d9 RSI: 00002000000000c0 RDI: 0000000000000002
RBP: 00007ffb32613f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffb327e6038 R14: 00007ffb327e5fa0 R15: 00007fff53201c58
WARNING: CPU: 0 PID: 12837 at kernel/sched/sched.h:1538 lockdep_assert_rq_held kernel/sched/sched.h:1538 [inline]
WARNING: CPU: 0 PID: 12837 at kernel/sched/sched.h:1538 lockdep_assert_rq_held kernel/sched/sched.h:1536 [inline]
WARNING: CPU: 0 PID: 12837 at kernel/sched/sched.h:1538 update_rq_clock+0x34a/0xc70 kernel/sched/core.c:836
Modules linked in:
CPU: 0 UID: 0 PID: 12837 Comm: syz.0.1760 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:lockdep_assert_rq_held kernel/sched/sched.h:1538 [inline]
RIP: 0010:lockdep_assert_rq_held kernel/sched/sched.h:1536 [inline]
RIP: 0010:update_rq_clock+0x34a/0xc70 kernel/sched/core.c:836
Code: ab 48 0b 00 00 48 83 c4 18 5b 5d 41 5c 41 5d 41 5e 41 5f e9 88 f8 d6 09 a8 04 0f 84 9c fd ff ff 90 0f 0b 90 e9 93 fd ff ff 90 <0f> 0b 90 e9 4f fd ff ff 48 8d bb 18 0e 00 00 48 b8 00 00 00 00 00
RSP: 0018:ffffc90004337800 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffff8880b853a4c0 RCX: 0000000000000001
RDX: 0000000000000000 RSI: ffffffff8da03cc9 RDI: ffffffff8bf07940
RBP: 0000000000000001 R08: 0000000000000000 R09: fffffbfff2104a7a
R10: ffffffff908253d7 R11: 0000000000000001 R12: ffffffff90828434
R13: ffff88801d2dbc80 R14: ffff8880b853a4c0 R15: ffff8880b843afc8
FS: 00007ffb334386c0(0000) GS:ffff888124a0d000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000010e000 CR3: 00000000774b0000 CR4: 00000000003526f0
Call Trace:
pick_next_task kernel/sched/core.c:6158 [inline]
__schedule+0x27fc/0x5de0 kernel/sched/core.c:6870
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:702
RIP: 0010:queue_work_on+0x86/0x1f0 kernel/workqueue.c:2397
Code: 38 00 45 84 f6 74 38 e8 48 ba 38 00 9c 5b 81 e3 00 02 00 00 31 ff 48 89 de e8 a6 b5 38 00 48 85 db 0f 85 4f 01 00 00 45 31 f6 25 ba 38 00 44 89 f0 5b 5d 41 5c 41 5d 41 5e c3 cc cc cc cc e8
RSP: 0018:ffffc90004337ae8 EFLAGS: 00000283
RAX: 000000000002885e RBX: 0000000000000000 RCX: ffffc9000be89000
RDX: 0000000000080000 RSI: ffffffff81839e26 RDI: 0000000000000007
RBP: 0000000000000200 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000008
R13: ffff88813ff15c00 R14: 0000000000000001 R15: ffff88802fe74600
queue_work include/linux/workqueue.h:669 [inline]
snd_virmidi_output_trigger+0xf1/0x130 sound/core/seq/seq_virmidi.c:178
snd_rawmidi_output_trigger sound/core/rawmidi.c:213 [inline]
snd_rawmidi_output_trigger sound/core/rawmidi.c:209 [inline]
snd_rawmidi_kernel_write1+0x3fb/0x8a0 sound/core/rawmidi.c:1576
snd_rawmidi_write+0x26e/0xc10 sound/core/rawmidi.c:1629
vfs_write+0x2a0/0x11d0 fs/read_write.c:684
ksys_write+0x1f8/0x250 fs/read_write.c:738
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ffb3258f7c9
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:00007ffb33438038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007ffb327e5fa0 RCX: 00007ffb3258f7c9
RDX: 000000100000e3d9 RSI: 00002000000000c0 RDI: 0000000000000002
RBP: 00007ffb32613f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffb327e6038 R14: 00007ffb327e5fa0 R15: 00007fff53201c58
----------------
Code disassembly (best guess):
0: 38 00 cmp %al,(%rax)
2: 45 84 f6 test %r14b,%r14b
5: 74 38 je 0x3f
7: e8 48 ba 38 00 call 0x38ba54
c: 9c pushf
d: 5b pop %rbx
e: 81 e3 00 02 00 00 and $0x200,%ebx
14: 31 ff xor %edi,%edi
16: 48 89 de mov %rbx,%rsi
19: e8 a6 b5 38 00 call 0x38b5c4
1e: 48 85 db test %rbx,%rbx
21: 0f 85 4f 01 00 00 jne 0x176
27: 45 31 f6 xor %r14d,%r14d
* 2a: e8 25 ba 38 00 call 0x38ba54 <-- trapping instruction
2f: 44 89 f0 mov %r14d,%eax
32: 5b pop %rbx
33: 5d pop %rbp
34: 41 5c pop %r12
36: 41 5d pop %r13
38: 41 5e pop %r14
3a: c3 ret
3b: cc int3
3c: cc int3
3d: cc int3
3e: cc int3
3f: e8 .byte 0xe8