------------[ cut here ]------------
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.0.1554/13778 is trying to acquire lock:
ffffffff8e2d1540 (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: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+0x47/0x60 drivers/tty/tty_port.c:67
       serial8250_tx_chars+0x68e/0x860 drivers/tty/serial/8250/8250_port.c:1719
       serial8250_handle_irq+0x761/0xcb0 drivers/tty/serial/8250/8250_port.c:1827
       serial8250_default_handle_irq+0x9e/0x270 drivers/tty/serial/8250/8250_port.c:1846
       serial8250_interrupt+0xf5/0x1d0 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+0xcd/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
       native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline]
       pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:81
       arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
       default_idle+0x13/0x20 arch/x86/kernel/process.c:767
       default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122
       cpuidle_idle_call kernel/sched/idle.c:190 [inline]
       do_idle+0x38d/0x500 kernel/sched/idle.c:330
       cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:428
       rest_init+0x16b/0x2b0 init/main.c:757
       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

-> #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
       serial8250_handle_irq+0x761/0xcb0 drivers/tty/serial/8250/8250_port.c:1827
       serial8250_default_handle_irq+0x9e/0x270 drivers/tty/serial/8250/8250_port.c:1846
       serial8250_interrupt+0xf5/0x1d0 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+0xcd/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:634
       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+0x500/0x9b0 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+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
       __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:621
       lockdep_assert_rq_held kernel/sched/sched.h:1537 [inline]
       lockdep_assert_rq_held kernel/sched/sched.h:1535 [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_common+0x44/0xc0 kernel/sched/core.c:7113
       preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
       __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline]
       _raw_spin_unlock_irq+0x44/0x50 kernel/locking/spinlock.c:202
       spin_unlock_irq include/linux/spinlock.h:401 [inline]
       snd_rawmidi_write+0x48c/0xc10 sound/core/rawmidi.c:1615
       vfs_write+0x29d/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.0.1554/13778:
 #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: ffffffff8e3b1980 (console_lock){+.+.}-{0:0}, at: _printk+0xc7/0x100 kernel/printk/printk.c:2448
 #2: ffffffff8e3b19f0 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:336 [inline]
 #2: ffffffff8e3b19f0 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:335 [inline]
 #2: ffffffff8e3b19f0 (console_srcu){....}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:289 [inline]
 #2: ffffffff8e3b19f0 (console_srcu){....}-{0:0}, at: console_flush_all+0x158/0xc60 kernel/printk/printk.c:3176

stack backtrace:
CPU: 0 UID: 0 PID: 13778 Comm: syz.0.1554 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
 <TASK>
 __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
 __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:621
RIP: 0010:lockdep_assert_rq_held kernel/sched/sched.h:1537 [inline]
RIP: 0010:lockdep_assert_rq_held kernel/sched/sched.h:1535 [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 c3 cc cc cc cc 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:ffffc900034c7938 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffff8880b853a4c0 RCX: 0000000000000001
RDX: 0000000000000000 RSI: ffffffff8dad999a RDI: ffffffff8bf1d540
RBP: 0000000000000001 R08: 0000000000000000 R09: fffffbfff2106b1a
R10: ffffffff908358d7 R11: 0000000000000001 R12: ffffffff90838934
R13: ffff88801d6e3c80 R14: ffff8880b853a4c0 R15: ffff8880b843afc8
 pick_next_task kernel/sched/core.c:6158 [inline]
 __schedule+0x27fc/0x5de0 kernel/sched/core.c:6870
 preempt_schedule_common+0x44/0xc0 kernel/sched/core.c:7113
 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline]
 _raw_spin_unlock_irq+0x44/0x50 kernel/locking/spinlock.c:202
 spin_unlock_irq include/linux/spinlock.h:401 [inline]
 snd_rawmidi_write+0x48c/0xc10 sound/core/rawmidi.c:1615
 vfs_write+0x29d/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: 0033:0x7fcf4e18eec9
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:00007fcf4ef8c038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fcf4e3e6180 RCX: 00007fcf4e18eec9
RDX: 000000100000a3d9 RSI: 00002000000005c0 RDI: 0000000000000002
RBP: 00007fcf4e211f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fcf4e3e6218 R14: 00007fcf4e3e6180 R15: 00007fffa30ffe68
 </TASK>
WARNING: CPU: 0 PID: 13778 at kernel/sched/sched.h:1537 lockdep_assert_rq_held kernel/sched/sched.h:1537 [inline]
WARNING: CPU: 0 PID: 13778 at kernel/sched/sched.h:1537 lockdep_assert_rq_held kernel/sched/sched.h:1535 [inline]
WARNING: CPU: 0 PID: 13778 at kernel/sched/sched.h:1537 update_rq_clock+0x34a/0xc70 kernel/sched/core.c:836
Modules linked in:
CPU: 0 UID: 0 PID: 13778 Comm: syz.0.1554 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:lockdep_assert_rq_held kernel/sched/sched.h:1537 [inline]
RIP: 0010:lockdep_assert_rq_held kernel/sched/sched.h:1535 [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 c3 cc cc cc cc 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:ffffc900034c7938 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffff8880b853a4c0 RCX: 0000000000000001
RDX: 0000000000000000 RSI: ffffffff8dad999a RDI: ffffffff8bf1d540
RBP: 0000000000000001 R08: 0000000000000000 R09: fffffbfff2106b1a
R10: ffffffff908358d7 R11: 0000000000000001 R12: ffffffff90838934
R13: ffff88801d6e3c80 R14: ffff8880b853a4c0 R15: ffff8880b843afc8
FS:  00007fcf4ef8c6c0(0000) GS:ffff8881249e7000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fcf4e3e5f90 CR3: 0000000076a06000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 pick_next_task kernel/sched/core.c:6158 [inline]
 __schedule+0x27fc/0x5de0 kernel/sched/core.c:6870
 preempt_schedule_common+0x44/0xc0 kernel/sched/core.c:7113
 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline]
 _raw_spin_unlock_irq+0x44/0x50 kernel/locking/spinlock.c:202
 spin_unlock_irq include/linux/spinlock.h:401 [inline]
 snd_rawmidi_write+0x48c/0xc10 sound/core/rawmidi.c:1615
 vfs_write+0x29d/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: 0033:0x7fcf4e18eec9
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:00007fcf4ef8c038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fcf4e3e6180 RCX: 00007fcf4e18eec9
RDX: 000000100000a3d9 RSI: 00002000000005c0 RDI: 0000000000000002
RBP: 00007fcf4e211f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fcf4e3e6218 R14: 00007fcf4e3e6180 R15: 00007fffa30ffe68
 </TASK>