------------[ cut here ]------------
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Tainted: G             L     
------------------------------------------------------
syz.0.1040/11128 is trying to acquire lock:
ffffffff8eaf4160 (console_owner){-.-.}-{0:0}, at: console_lock_spinning_enable+0x61/0x80 kernel/printk/printk.c:1902

but task is already holding lock:
ffff8880b843b520 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:675 [inline]
ffff8880b843b520 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x88/0x140 kernel/sched/core.c:659

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #4 (&rq->__lock){-.-.}-{2:2}:
       lock_acquire kernel/locking/lockdep.c:5868 [inline]
       lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5825
       _raw_spin_lock_nested+0x31/0x40 kernel/locking/spinlock.c:382
       raw_spin_rq_lock_nested+0x2c/0x140 kernel/sched/core.c:667
       raw_spin_rq_lock kernel/sched/sched.h:1653 [inline]
       _task_rq_lock+0xcf/0x500 kernel/sched/core.c:762
       cgroup_move_task+0x81/0x320 kernel/sched/psi.c:1176
       css_set_move_task+0x285/0x600 kernel/cgroup/cgroup.c:925
       cgroup_post_fork+0x1f9/0x9a0 kernel/cgroup/cgroup.c:7009
       copy_process+0x6b7a/0x8030 kernel/fork.c:2550
       kernel_clone+0x176/0x9d0 kernel/fork.c:2748
       user_mode_thread+0xcc/0x110 kernel/fork.c:2824
       rest_init+0x21/0x260 init/main.c:682
       start_kernel+0x48e/0x490 init/main.c:1175
       x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
       x86_64_start_kernel+0x12b/0x130 arch/x86/kernel/head64.c:291
       common_startup_64+0x13e/0x158

-> #3 (&p->pi_lock){-.-.}-{2:2}:
       lock_acquire kernel/locking/lockdep.c:5868 [inline]
       lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5825
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline]
       _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:166
       class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:571 [inline]
       try_to_wake_up+0xbd/0x1c90 kernel/sched/core.c:4292
       __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+0x68f/0x860 drivers/tty/serial/8250/8250_port.c:1723
       serial8250_handle_irq_locked+0x770/0x9a0 drivers/tty/serial/8250/8250_port.c:1837
       serial8250_handle_irq.part.0+0xb4/0x530 drivers/tty/serial/8250/8250_port.c:1853
       serial8250_handle_irq drivers/tty/serial/8250/8250_port.c:1849 [inline]
       serial8250_default_handle_irq+0xc2/0x280 drivers/tty/serial/8250/8250_port.c:1867
       serial8250_interrupt+0xf8/0x1b0 drivers/tty/serial/8250/8250_core.c:86
       __handle_irq_event_percpu+0x232/0x880 kernel/irq/handle.c:209
       handle_irq_event_percpu kernel/irq/handle.c:246 [inline]
       handle_irq_event+0xab/0x1e0 kernel/irq/handle.c:263
       handle_edge_irq+0x34c/0x950 kernel/irq/chip.c:859
       generic_handle_irq_desc include/linux/irqdesc.h:188 [inline]
       handle_irq arch/x86/kernel/irq.c:209 [inline]
       call_irq_handler arch/x86/kernel/irq.c:265 [inline]
       __common_interrupt+0xd8/0x2f0 arch/x86/kernel/irq.c:280
       common_interrupt+0xb9/0xe0 arch/x86/kernel/irq.c:273
       asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:665
       __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:188 [inline]
       _raw_spin_unlock_irq+0x29/0x50 kernel/locking/spinlock.c:206
       spin_unlock_irq include/linux/spinlock.h:402 [inline]
       __rpm_callback+0x272/0x620 drivers/base/power/runtime.c:383
       rpm_callback+0x16a/0x1b0 drivers/base/power/runtime.c:460
       rpm_resume+0xd13/0x1320 drivers/base/power/runtime.c:939
       rpm_resume+0x721/0x1320 drivers/base/power/runtime.c:917
       pm_runtime_work+0x10c/0x150 drivers/base/power/runtime.c:1004
       process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
       process_scheduled_works kernel/workqueue.c:3405 [inline]
       worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
       kthread+0x370/0x450 kernel/kthread.c:436
       ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #2 (&tty->write_wait){-.-.}-{3:3}:
       lock_acquire kernel/locking/lockdep.c:5868 [inline]
       lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5825
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline]
       _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:166
       __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+0x68f/0x860 drivers/tty/serial/8250/8250_port.c:1723
       serial8250_handle_irq_locked+0x770/0x9a0 drivers/tty/serial/8250/8250_port.c:1837
       serial8250_handle_irq.part.0+0xb4/0x530 drivers/tty/serial/8250/8250_port.c:1853
       serial8250_handle_irq drivers/tty/serial/8250/8250_port.c:1849 [inline]
       serial8250_default_handle_irq+0xc2/0x280 drivers/tty/serial/8250/8250_port.c:1867
       serial8250_interrupt+0xf8/0x1b0 drivers/tty/serial/8250/8250_core.c:86
       __handle_irq_event_percpu+0x232/0x880 kernel/irq/handle.c:209
       handle_irq_event_percpu kernel/irq/handle.c:246 [inline]
       handle_irq_event+0xab/0x1e0 kernel/irq/handle.c:263
       handle_edge_irq+0x34c/0x950 kernel/irq/chip.c:859
       generic_handle_irq_desc include/linux/irqdesc.h:188 [inline]
       handle_irq arch/x86/kernel/irq.c:209 [inline]
       call_irq_handler arch/x86/kernel/irq.c:265 [inline]
       __common_interrupt+0xd8/0x2f0 arch/x86/kernel/irq.c:280
       common_interrupt+0xb9/0xe0 arch/x86/kernel/irq.c:273
       asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:665
       native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline]
       pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:63
       arch_safe_halt arch/x86/include/asm/paravirt.h:62 [inline]
       default_idle+0x9/0x10 arch/x86/kernel/process.c:768
       default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122
       cpuidle_idle_call kernel/sched/idle.c:199 [inline]
       do_idle+0x3a7/0x5b0 kernel/sched/idle.c:355
       cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:454
       start_secondary+0x21d/0x2d0 arch/x86/kernel/smpboot.c:312
       common_startup_64+0x13e/0x158

-> #1 (&port_lock_key){-.-.}-{3:3}:
       lock_acquire kernel/locking/lockdep.c:5868 [inline]
       lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5825
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline]
       _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:166
       uart_port_lock_irqsave include/linux/serial_core.h:719 [inline]
       serial8250_console_write+0x177/0x1a50 drivers/tty/serial/8250/8250_port.c:3344
       console_emit_next_record kernel/printk/printk.c:3183 [inline]
       console_flush_one_record+0x790/0xe50 kernel/printk/printk.c:3269
       console_flush_all kernel/printk/printk.c:3343 [inline]
       __console_flush_and_unlock kernel/printk/printk.c:3373 [inline]
       console_unlock+0x103/0x260 kernel/printk/printk.c:3413
       vprintk_emit+0x407/0x6b0 kernel/printk/printk.c:2479
       _printk+0xcf/0x110 kernel/printk/printk.c:2504
       register_console.cold+0xc0/0x248 kernel/printk/printk.c:4208
       univ8250_console_init+0x6f/0x80 drivers/tty/serial/8250/8250_core.c:515
       console_init+0x3d5/0x5b0 kernel/printk/printk.c:4407
       start_kernel+0x314/0x490 init/main.c:1112
       x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
       x86_64_start_kernel+0x12b/0x130 arch/x86/kernel/head64.c:291
       common_startup_64+0x13e/0x158

-> #0 (console_owner){-.-.}-{0:0}:
       check_prev_add+0xeb/0xe60 kernel/locking/lockdep.c:3165
       check_prevs_add kernel/locking/lockdep.c:3284 [inline]
       validate_chain kernel/locking/lockdep.c:3908 [inline]
       __lock_acquire+0x136c/0x1a40 kernel/locking/lockdep.c:5237
       lock_acquire kernel/locking/lockdep.c:5868 [inline]
       lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5825
       console_lock_spinning_enable+0x72/0x80 kernel/printk/printk.c:1902
       console_emit_next_record kernel/printk/printk.c:3177 [inline]
       console_flush_one_record+0x739/0xe50 kernel/printk/printk.c:3269
       console_flush_all kernel/printk/printk.c:3343 [inline]
       __console_flush_and_unlock kernel/printk/printk.c:3373 [inline]
       console_unlock+0x103/0x260 kernel/printk/printk.c:3413
       vprintk_emit+0x407/0x6b0 kernel/printk/printk.c:2479
       _printk+0xcf/0x110 kernel/printk/printk.c:2504
       __report_bug.cold+0x34/0x141 lib/bug.c:248
       report_bug+0xb2/0x220 lib/bug.c:286
       handle_bug+0x16a/0x2a0 arch/x86/kernel/traps.c:436
       exc_invalid_op+0x17/0x50 arch/x86/kernel/traps.c:490
       asm_exc_invalid_op+0x1a/0x20 arch/x86/include/asm/idtentry.h:593
       lockdep_assert_rq_held kernel/sched/sched.h:1641 [inline]
       lockdep_assert_rq_held kernel/sched/sched.h:1638 [inline]
       update_rq_clock+0x40a/0xd20 kernel/sched/core.c:865
       pick_next_task kernel/sched/core.c:6338 [inline]
       __schedule+0x1e2d/0x6730 kernel/sched/core.c:7149
       __schedule_loop kernel/sched/core.c:7311 [inline]
       schedule+0xdd/0x2c0 kernel/sched/core.c:7326
       do_nanosleep+0x113/0x500 kernel/time/hrtimer.c:2399
       hrtimer_nanosleep+0x14f/0x350 kernel/time/hrtimer.c:2445
       common_nsleep+0xa1/0xd0 kernel/time/posix-timers.c:1360
       __do_sys_clock_nanosleep kernel/time/posix-timers.c:1406 [inline]
       __se_sys_clock_nanosleep kernel/time/posix-timers.c:1383 [inline]
       __x64_sys_clock_nanosleep+0x336/0x480 kernel/time/posix-timers.c:1383
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0x115/0x870 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.0.1040/11128:
 #0: ffff8880b843b520 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:675 [inline]
 #0: ffff8880b843b520 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x88/0x140 kernel/sched/core.c:659
 #1: ffffffff8ebd45a0 (console_lock){+.+.}-{0:0}, at: _printk+0xcf/0x110 kernel/printk/printk.c:2504
 #2: ffffffff8ebd4618 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:305 [inline]
 #2: ffffffff8ebd4618 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:428 [inline]
 #2: ffffffff8ebd4618 (console_srcu){....}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:291 [inline]
 #2: ffffffff8ebd4618 (console_srcu){....}-{0:0}, at: console_flush_one_record+0xfd/0xe50 kernel/printk/printk.c:3246

stack backtrace:
CPU: 0 UID: 0 PID: 11128 Comm: syz.0.1040 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_circular_bug.cold+0x178/0x1c7 kernel/locking/lockdep.c:2043
 check_noncircular+0x146/0x160 kernel/locking/lockdep.c:2175
 check_prev_add+0xeb/0xe60 kernel/locking/lockdep.c:3165
 check_prevs_add kernel/locking/lockdep.c:3284 [inline]
 validate_chain kernel/locking/lockdep.c:3908 [inline]
 __lock_acquire+0x136c/0x1a40 kernel/locking/lockdep.c:5237
 lock_acquire kernel/locking/lockdep.c:5868 [inline]
 lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5825
 console_lock_spinning_enable+0x72/0x80 kernel/printk/printk.c:1902
 console_emit_next_record kernel/printk/printk.c:3177 [inline]
 console_flush_one_record+0x739/0xe50 kernel/printk/printk.c:3269
 console_flush_all kernel/printk/printk.c:3343 [inline]
 __console_flush_and_unlock kernel/printk/printk.c:3373 [inline]
 console_unlock+0x103/0x260 kernel/printk/printk.c:3413
 vprintk_emit+0x407/0x6b0 kernel/printk/printk.c:2479
 _printk+0xcf/0x110 kernel/printk/printk.c:2504
 __report_bug.cold+0x34/0x141 lib/bug.c:248
 report_bug+0xb2/0x220 lib/bug.c:286
 handle_bug+0x16a/0x2a0 arch/x86/kernel/traps.c:436
 exc_invalid_op+0x17/0x50 arch/x86/kernel/traps.c:490
 asm_exc_invalid_op+0x1a/0x20 arch/x86/include/asm/idtentry.h:593
RIP: 0010:lockdep_assert_rq_held kernel/sched/sched.h:1641 [inline]
RIP: 0010:lockdep_assert_rq_held kernel/sched/sched.h:1638 [inline]
RIP: 0010:update_rq_clock+0x40a/0xd20 kernel/sched/core.c:865
Code: ab c8 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 df fc ff ff 90 0f 0b 90 e9 d6 fc ff ff 90 <0f> 0b 90 e9 92 fc ff ff 4c 8d 83 c0 0b 00 00 48 b8 00 00 00 00 00
RSP: 0018:ffffc90004717a88 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffff8880b853b4c0 RCX: 0000000000000001
RDX: 0000000000000046 RSI: ffffffff8e1810a7 RDI: ffffffff8c3ffa80
RBP: ffffc90004717c30 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff9121f5d7 R11: 00000000000003f6 R12: ffffffff912229a4
R13: ffff8880b853c3a0 R14: ffff88807f368000 R15: ffff8880b843c058
 pick_next_task kernel/sched/core.c:6338 [inline]
 __schedule+0x1e2d/0x6730 kernel/sched/core.c:7149
 __schedule_loop kernel/sched/core.c:7311 [inline]
 schedule+0xdd/0x2c0 kernel/sched/core.c:7326
 do_nanosleep+0x113/0x500 kernel/time/hrtimer.c:2399
 hrtimer_nanosleep+0x14f/0x350 kernel/time/hrtimer.c:2445
 common_nsleep+0xa1/0xd0 kernel/time/posix-timers.c:1360
 __do_sys_clock_nanosleep kernel/time/posix-timers.c:1406 [inline]
 __se_sys_clock_nanosleep kernel/time/posix-timers.c:1383 [inline]
 __x64_sys_clock_nanosleep+0x336/0x480 kernel/time/posix-timers.c:1383
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5ee4d5e90e
Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08
RSP: 002b:00007ffdd1f3a9e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e6
RAX: ffffffffffffffda RBX: 0000555559697500 RCX: 00007f5ee4d5e90e
RDX: 00007ffdd1f3aa40 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f5ee5027da0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000004cd6d
R13: 00007f5ee502618c R14: 000000000004c1e7 R15: 00007f5ee5026180
 </TASK>
debug_locks && !(lock_is_held(&(__rq_lockp(rq))->dep_map) != 0)
WARNING: kernel/sched/sched.h:1641 at lockdep_assert_rq_held kernel/sched/sched.h:1641 [inline], CPU#0: syz.0.1040/11128
WARNING: kernel/sched/sched.h:1641 at lockdep_assert_rq_held kernel/sched/sched.h:1638 [inline], CPU#0: syz.0.1040/11128
WARNING: kernel/sched/sched.h:1641 at update_rq_clock+0x40a/0xd20 kernel/sched/core.c:865, CPU#0: syz.0.1040/11128
Modules linked in:
CPU: 0 UID: 0 PID: 11128 Comm: syz.0.1040 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:lockdep_assert_rq_held kernel/sched/sched.h:1641 [inline]
RIP: 0010:lockdep_assert_rq_held kernel/sched/sched.h:1638 [inline]
RIP: 0010:update_rq_clock+0x40a/0xd20 kernel/sched/core.c:865
Code: ab c8 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 df fc ff ff 90 0f 0b 90 e9 d6 fc ff ff 90 <0f> 0b 90 e9 92 fc ff ff 4c 8d 83 c0 0b 00 00 48 b8 00 00 00 00 00
RSP: 0018:ffffc90004717a88 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffff8880b853b4c0 RCX: 0000000000000001
RDX: 0000000000000046 RSI: ffffffff8e1810a7 RDI: ffffffff8c3ffa80
RBP: ffffc90004717c30 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff9121f5d7 R11: 00000000000003f6 R12: ffffffff912229a4
R13: ffff8880b853c3a0 R14: ffff88807f368000 R15: ffff8880b843c058
FS:  0000555559697500(0000) GS:ffff888123ded000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffb0d5f3b2d CR3: 000000007efa4000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 pick_next_task kernel/sched/core.c:6338 [inline]
 __schedule+0x1e2d/0x6730 kernel/sched/core.c:7149
 __schedule_loop kernel/sched/core.c:7311 [inline]
 schedule+0xdd/0x2c0 kernel/sched/core.c:7326
 do_nanosleep+0x113/0x500 kernel/time/hrtimer.c:2399
 hrtimer_nanosleep+0x14f/0x350 kernel/time/hrtimer.c:2445
 common_nsleep+0xa1/0xd0 kernel/time/posix-timers.c:1360
 __do_sys_clock_nanosleep kernel/time/posix-timers.c:1406 [inline]
 __se_sys_clock_nanosleep kernel/time/posix-timers.c:1383 [inline]
 __x64_sys_clock_nanosleep+0x336/0x480 kernel/time/posix-timers.c:1383
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5ee4d5e90e
Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08
RSP: 002b:00007ffdd1f3a9e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e6
RAX: ffffffffffffffda RBX: 0000555559697500 RCX: 00007f5ee4d5e90e
RDX: 00007ffdd1f3aa40 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f5ee5027da0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000004cd6d
R13: 00007f5ee502618c R14: 000000000004c1e7 R15: 00007f5ee5026180
 </TASK>