------------[ cut here ]------------
======================================================
WARNING: possible circular locking dependency detected
6.16.0-syzkaller-06699-ge8d780dcd957 #0 Not tainted
------------------------------------------------------
migration/0/19 is trying to acquire lock:
ffffffff8e4d0ee0 (console_owner){-.-.}-{0:0}, at: console_lock_spinning_enable+0x9f/0xd0 kernel/printk/printk.c:1924

but task is already holding lock:
ffff8880b843a458 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:644 [inline]
ffff8880b843a458 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x7e/0x130 kernel/sched/core.c:629

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:636
       raw_spin_rq_lock kernel/sched/sched.h:1522 [inline]
       task_rq_lock+0xcf/0x490 kernel/sched/core.c:736
       cgroup_move_task+0x81/0x2a0 kernel/sched/psi.c:1174
       css_set_move_task+0x288/0x5f0 kernel/cgroup/cgroup.c:918
       cgroup_post_fork+0x201/0x9e0 kernel/cgroup/cgroup.c:6759
       copy_process+0x5cfa/0x7690 kernel/fork.c:2416
       kernel_clone+0xfc/0x930 kernel/fork.c:2602
       user_mode_thread+0xc7/0x110 kernel/fork.c:2680
       rest_init+0x23/0x2b0 init/main.c:709
       start_kernel+0x3ee/0x4d0 init/main.c:1097
       x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:307
       x86_64_start_kernel+0x130/0x190 arch/x86/kernel/head64.c:288
       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+0xb2/0x1680 kernel/sched/core.c:4210
       __wake_up_common+0x135/0x1f0 kernel/sched/wait.c:90
       __wake_up_common_lock kernel/sched/wait.c:107 [inline]
       __wake_up+0x31/0x60 kernel/sched/wait.c:128
       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+0xf8/0x1b0 drivers/tty/serial/8250/8250_core.c:82
       __handle_irq_event_percpu+0x229/0x7d0 kernel/irq/handle.c:158
       handle_irq_event_percpu kernel/irq/handle.c:193 [inline]
       handle_irq_event+0xab/0x1e0 kernel/irq/handle.c:210
       handle_edge_irq+0x3b3/0x9d0 kernel/irq/chip.c:849
       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:266 [inline]
       __common_interrupt+0xdf/0x250 arch/x86/kernel/irq.c:292
       common_interrupt+0xba/0xe0 arch/x86/kernel/irq.c:285
       asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693
       ___slab_alloc+0x378/0x1780 mm/slub.c:3800
       __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3980
       __slab_alloc_node mm/slub.c:4055 [inline]
       slab_alloc_node mm/slub.c:4216 [inline]
       kmem_cache_alloc_noprof+0xef/0x3b0 mm/slub.c:4235
       anon_vma_chain_alloc mm/rmap.c:142 [inline]
       anon_vma_clone+0xd8/0x5c0 mm/rmap.c:288
       anon_vma_fork+0x7a/0x620 mm/rmap.c:351
       dup_mmap+0x152e/0x21d0 mm/mmap.c:1801
       dup_mm kernel/fork.c:1481 [inline]
       copy_mm kernel/fork.c:1533 [inline]
       copy_process+0x4081/0x7690 kernel/fork.c:2172
       kernel_clone+0xfc/0x930 kernel/fork.c:2602
       __do_sys_clone+0xce/0x120 kernel/fork.c:2745
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xcd/0x490 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:106 [inline]
       __wake_up+0x1c/0x60 kernel/sched/wait.c:128
       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+0xf8/0x1b0 drivers/tty/serial/8250/8250_core.c:82
       __handle_irq_event_percpu+0x229/0x7d0 kernel/irq/handle.c:158
       handle_irq_event_percpu kernel/irq/handle.c:193 [inline]
       handle_irq_event+0xab/0x1e0 kernel/irq/handle.c:210
       handle_edge_irq+0x3b3/0x9d0 kernel/irq/chip.c:849
       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:266 [inline]
       __common_interrupt+0xdf/0x250 arch/x86/kernel/irq.c:292
       common_interrupt+0xba/0xe0 arch/x86/kernel/irq.c:285
       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+0x40f/0x1160 drivers/tty/n_tty.c:2377
       iterate_tty_write drivers/tty/tty_io.c:1006 [inline]
       file_tty_write.constprop.0+0x504/0x9b0 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+0x6c4/0x1150 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/0x490 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:3138 [inline]
       console_flush_all+0x801/0xc60 kernel/printk/printk.c:3226
       __console_flush_and_unlock kernel/printk/printk.c:3285 [inline]
       console_unlock+0xd8/0x210 kernel/printk/printk.c:3325
       vprintk_emit+0x418/0x6d0 kernel/printk/printk.c:2450
       _printk+0xc7/0x100 kernel/printk/printk.c:2475
       register_console+0xc2d/0x11b0 kernel/printk/printk.c:4125
       univ8250_console_init+0x5f/0x90 drivers/tty/serial/8250/8250_core.c:516
       console_init+0x14f/0x680 kernel/printk/printk.c:4323
       start_kernel+0x29f/0x4d0 init/main.c:1035
       x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:307
       x86_64_start_kernel+0x130/0x190 arch/x86/kernel/head64.c:288
       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+0xb0/0xd0 kernel/printk/printk.c:1924
       console_emit_next_record kernel/printk/printk.c:3132 [inline]
       console_flush_all+0x7aa/0xc60 kernel/printk/printk.c:3226
       __console_flush_and_unlock kernel/printk/printk.c:3285 [inline]
       console_unlock+0xd8/0x210 kernel/printk/printk.c:3325
       vprintk_emit+0x418/0x6d0 kernel/printk/printk.c:2450
       _printk+0xc7/0x100 kernel/printk/printk.c:2475
       __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:1513 [inline]
       lockdep_assert_rq_held kernel/sched/sched.h:1511 [inline]
       update_rq_clock+0x34a/0xc70 kernel/sched/core.c:834
       pick_next_task kernel/sched/core.c:6184 [inline]
       __schedule+0x2807/0x5df0 kernel/sched/core.c:6895
       __schedule_loop kernel/sched/core.c:7036 [inline]
       schedule+0xe7/0x3a0 kernel/sched/core.c:7051
       smpboot_thread_fn+0x8e6/0xae0 kernel/smpboot.c:156
       kthread+0x3c5/0x780 kernel/kthread.c:464
       ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

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 migration/0/19:
 #0: ffff8880b843a458 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:644 [inline]
 #0: ffff8880b843a458 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x7e/0x130 kernel/sched/core.c:629
 #1: ffffffff8e5b1320 (console_lock){+.+.}-{0:0}, at: _printk+0xc7/0x100 kernel/printk/printk.c:2475
 #2: ffffffff8e5b1390 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:336 [inline]
 #2: ffffffff8e5b1390 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:319 [inline]
 #2: ffffffff8e5b1390 (console_srcu){....}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:288 [inline]
 #2: ffffffff8e5b1390 (console_srcu){....}-{0:0}, at: console_flush_all+0x158/0xc60 kernel/printk/printk.c:3203

stack backtrace:
CPU: 0 UID: 0 PID: 19 Comm: migration/0 Not tainted 6.16.0-syzkaller-06699-ge8d780dcd957 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Stopper: 0x0 <- 0x0
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+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+0xb0/0xd0 kernel/printk/printk.c:1924
 console_emit_next_record kernel/printk/printk.c:3132 [inline]
 console_flush_all+0x7aa/0xc60 kernel/printk/printk.c:3226
 __console_flush_and_unlock kernel/printk/printk.c:3285 [inline]
 console_unlock+0xd8/0x210 kernel/printk/printk.c:3325
 vprintk_emit+0x418/0x6d0 kernel/printk/printk.c:2450
 _printk+0xc7/0x100 kernel/printk/printk.c:2475
 __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:1513 [inline]
RIP: 0010:lockdep_assert_rq_held kernel/sched/sched.h:1511 [inline]
RIP: 0010:update_rq_clock+0x34a/0xc70 kernel/sched/core.c:834
Code: ab 88 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 58 0e 00 00 48 b8 00 00 00 00 00
RSP: 0018:ffffc90000187be8 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffff8880b853a440 RCX: 0000000000000001
RDX: 0000000000000000 RSI: ffffffff8dde731c RDI: ffffffff8c15f400
RBP: 0000000000000001 R08: 0000000000001000 R09: ffffed100ca5ba00
R10: ffff8880652dd007 R11: 0000000000000001 R12: ffffffff90a81f24
R13: ffff888065ca1e00 R14: ffff8880b853a440 R15: ffff8880b843af50
 pick_next_task kernel/sched/core.c:6184 [inline]
 __schedule+0x2807/0x5df0 kernel/sched/core.c:6895
 __schedule_loop kernel/sched/core.c:7036 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:7051
 smpboot_thread_fn+0x8e6/0xae0 kernel/smpboot.c:156
 kthread+0x3c5/0x780 kernel/kthread.c:464
 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
WARNING: CPU: 0 PID: 19 at kernel/sched/sched.h:1513 lockdep_assert_rq_held kernel/sched/sched.h:1513 [inline]
WARNING: CPU: 0 PID: 19 at kernel/sched/sched.h:1513 lockdep_assert_rq_held kernel/sched/sched.h:1511 [inline]
WARNING: CPU: 0 PID: 19 at kernel/sched/sched.h:1513 update_rq_clock+0x34a/0xc70 kernel/sched/core.c:834
Modules linked in:
CPU: 0 UID: 0 PID: 19 Comm: migration/0 Not tainted 6.16.0-syzkaller-06699-ge8d780dcd957 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Stopper: 0x0 <- 0x0
RIP: 0010:lockdep_assert_rq_held kernel/sched/sched.h:1513 [inline]
RIP: 0010:lockdep_assert_rq_held kernel/sched/sched.h:1511 [inline]
RIP: 0010:update_rq_clock+0x34a/0xc70 kernel/sched/core.c:834
Code: ab 88 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 58 0e 00 00 48 b8 00 00 00 00 00
RSP: 0018:ffffc90000187be8 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffff8880b853a440 RCX: 0000000000000001
RDX: 0000000000000000 RSI: ffffffff8dde731c RDI: ffffffff8c15f400
RBP: 0000000000000001 R08: 0000000000001000 R09: ffffed100ca5ba00
R10: ffff8880652dd007 R11: 0000000000000001 R12: ffffffff90a81f24
R13: ffff888065ca1e00 R14: ffff8880b853a440 R15: ffff8880b843af50
FS:  0000000000000000(0000) GS:ffff88812472c000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000470000 CR3: 000000007790c000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 pick_next_task kernel/sched/core.c:6184 [inline]
 __schedule+0x2807/0x5df0 kernel/sched/core.c:6895
 __schedule_loop kernel/sched/core.c:7036 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:7051
 smpboot_thread_fn+0x8e6/0xae0 kernel/smpboot.c:156
 kthread+0x3c5/0x780 kernel/kthread.c:464
 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>