------------[ cut here ]------------
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Tainted: G             L     
------------------------------------------------------
syz-executor/5620 is trying to acquire lock:
ffffffff8eb4bf40 (console_owner){-.-.}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:305 [inline]
ffffffff8eb4bf40 (console_owner){-.-.}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:428 [inline]
ffffffff8eb4bf40 (console_owner){-.-.}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:291 [inline]
ffffffff8eb4bf40 (console_owner){-.-.}-{0:0}, at: console_flush_one_record kernel/printk/printk.c:3246 [inline]
ffffffff8eb4bf40 (console_owner){-.-.}-{0:0}, at: console_flush_all+0x123/0xaf0 kernel/printk/printk.c:3343

but task is already holding lock:
ffff8880b863b160 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xb2/0x160 kernel/sched/core.c:675

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #5 (&rq->__lock){-.-.}-{2:2}:
       _raw_spin_lock_nested+0x32/0x50 kernel/locking/spinlock.c:382
       raw_spin_rq_lock_nested+0x2d/0x160 kernel/sched/core.c:667
       raw_spin_rq_lock kernel/sched/sched.h:1653 [inline]
       _task_rq_lock+0xc0/0x440 kernel/sched/core.c:762
       cgroup_move_task+0x9a/0x350 kernel/sched/psi.c:1170
       css_set_move_task+0x62d/0x820 kernel/cgroup/cgroup.c:925
       cgroup_post_fork+0x209/0x9b0 kernel/cgroup/cgroup.c:6988
       copy_process+0x402b/0x4390 kernel/fork.c:2550
       kernel_clone+0x2d7/0x940 kernel/fork.c:2748
       user_mode_thread+0x110/0x180 kernel/fork.c:2824
       rest_init+0x23/0x300 init/main.c:682
       start_kernel+0x392/0x3e0 init/main.c:1175
       x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
       x86_64_start_kernel+0x137/0x1b0 arch/x86/kernel/head64.c:291
       common_startup_64+0x13e/0x157

-> #4 (&p->pi_lock){-.-.}-{2:2}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline]
       _raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:166
       class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:572 [inline]
       try_to_wake_up+0x67/0x14d0 kernel/sched/core.c:4292
       create_worker+0x5c1/0x7b0 kernel/workqueue.c:2893
       workqueue_init+0x3ea/0x680 kernel/workqueue.c:8169
       kernel_init_freeable+0x26b/0x3e0 init/main.c:1643
       kernel_init+0x1d/0x1d0 init/main.c:1548
       ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #3 (&pool->lock){-.-.}-{2:2}:
       __raw_spin_lock include/linux/spinlock_api_smp.h:158 [inline]
       _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:158
       __queue_work+0x72f/0x10a0 kernel/workqueue.c:2361
       queue_work_on+0x106/0x1d0 kernel/workqueue.c:2452
       queue_work include/linux/workqueue.h:699 [inline]
       rpm_suspend+0xeca/0x17b0 drivers/base/power/runtime.c:688
       __pm_runtime_idle+0x12f/0x1a0 drivers/base/power/runtime.c:1129
       pm_runtime_put include/linux/pm_runtime.h:551 [inline]
       __device_attach+0x355/0x450 drivers/base/dd.c:1116
       device_initial_probe+0xa1/0xd0 drivers/base/dd.c:1153
       bus_probe_device+0x12a/0x220 drivers/base/bus.c:620
       device_add+0x7d7/0xb80 drivers/base/core.c:3772
       serial_base_port_add+0x18f/0x270 drivers/tty/serial/serial_base_bus.c:186
       serial_core_port_device_add drivers/tty/serial/serial_core.c:3275 [inline]
       serial_core_register_port+0x37f/0x2840 drivers/tty/serial/serial_core.c:3314
       serial8250_register_8250_port+0x16b4/0x2090 drivers/tty/serial/8250/8250_core.c:828
       serial_pnp_probe+0x56a/0x7f0 drivers/tty/serial/8250/8250_pnp.c:480
       pnp_device_probe+0x30b/0x4c0 drivers/pnp/driver.c:111
       call_driver_probe drivers/base/dd.c:-1 [inline]
       really_probe+0x254/0xae0 drivers/base/dd.c:706
       __driver_probe_device+0x1e8/0x360 drivers/base/dd.c:868
       driver_probe_device+0x4f/0x240 drivers/base/dd.c:898
       __driver_attach+0x339/0x600 drivers/base/dd.c:1292
       bus_for_each_dev+0x23b/0x2c0 drivers/base/bus.c:383
       bus_add_driver+0x345/0x670 drivers/base/bus.c:763
       driver_register+0x23a/0x320 drivers/base/driver.c:174
       serial8250_init+0x8f/0x160 drivers/tty/serial/8250/8250_platform.c:317
       do_one_initcall+0x250/0x870 init/main.c:1347
       do_initcall_level+0x10a/0x1a0 init/main.c:1409
       do_initcalls+0x59/0xa0 init/main.c:1425
       kernel_init_freeable+0x29d/0x3e0 init/main.c:1658
       kernel_init+0x1d/0x1d0 init/main.c:1548
       ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #2 (&dev->power.lock){-...}-{3:3}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline]
       _raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:166
       __pm_runtime_resume+0x10f/0x180 drivers/base/power/runtime.c:1196
       pm_runtime_get include/linux/pm_runtime.h:494 [inline]
       __uart_start+0x171/0x460 drivers/tty/serial/serial_core.c:149
       uart_write+0x251/0x9f0 drivers/tty/serial/serial_core.c:629
       process_output_block drivers/tty/n_tty.c:557 [inline]
       n_tty_write+0xd49/0x11e0 drivers/tty/n_tty.c:2366
       iterate_tty_write drivers/tty/tty_io.c:1006 [inline]
       file_tty_write+0x509/0x9c0 drivers/tty/tty_io.c:1081
       new_sync_write fs/read_write.c:595 [inline]
       vfs_write+0x612/0xba0 fs/read_write.c:687
       ksys_write+0x150/0x270 fs/read_write.c:739
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0x174/0x580 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:132 [inline]
       _raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:166
       uart_port_lock_irqsave include/linux/serial_core.h:719 [inline]
       serial8250_console_write+0x153/0x1ba0 drivers/tty/serial/8250/8250_port.c:3344
       console_emit_next_record kernel/printk/printk.c:3183 [inline]
       console_flush_one_record kernel/printk/printk.c:3269 [inline]
       console_flush_all+0x6ea/0xaf0 kernel/printk/printk.c:3343
       __console_flush_and_unlock kernel/printk/printk.c:3373 [inline]
       console_unlock+0xd1/0x1c0 kernel/printk/printk.c:3413
       vprintk_emit+0x485/0x560 kernel/printk/printk.c:2479
       _printk+0xdd/0x130 kernel/printk/printk.c:2504
       register_console+0xbc3/0xfc0 kernel/printk/printk.c:4208
       univ8250_console_init+0x3a/0x70 drivers/tty/serial/8250/8250_core.c:515
       console_init+0x10b/0x4a0 kernel/printk/printk.c:4407
       start_kernel+0x238/0x3e0 init/main.c:1112
       x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
       x86_64_start_kernel+0x137/0x1b0 arch/x86/kernel/head64.c:291
       common_startup_64+0x13e/0x157

-> #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+0x1520/0x2cf0 kernel/locking/lockdep.c:5237
       lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
       console_lock_spinning_enable kernel/printk/printk.c:1902 [inline]
       console_emit_next_record kernel/printk/printk.c:3177 [inline]
       console_flush_one_record kernel/printk/printk.c:3269 [inline]
       console_flush_all+0x693/0xaf0 kernel/printk/printk.c:3343
       __console_flush_and_unlock kernel/printk/printk.c:3373 [inline]
       console_unlock+0xd1/0x1c0 kernel/printk/printk.c:3413
       vprintk_emit+0x485/0x560 kernel/printk/printk.c:2479
       _printk+0xdd/0x130 kernel/printk/printk.c:2504
       __report_bug+0x349/0x570 lib/bug.c:248
       report_bug+0x16a/0x220 lib/bug.c:286
       handle_bug+0x9c/0x200 arch/x86/kernel/traps.c:436
       exc_invalid_op+0x1a/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]
       update_rq_clock+0x34d/0x560 kernel/sched/core.c:865
       pick_next_task kernel/sched/core.c:6338 [inline]
       __schedule+0x388e/0x56c0 kernel/sched/core.c:7149
       __schedule_loop kernel/sched/core.c:7311 [inline]
       schedule+0x164/0x2b0 kernel/sched/core.c:7326
       do_nanosleep+0x21e/0x6a0 kernel/time/hrtimer.c:2399
       hrtimer_nanosleep+0x18f/0x3a0 kernel/time/hrtimer.c:2445
       __do_sys_clock_nanosleep kernel/time/posix-timers.c:1406 [inline]
       __se_sys_clock_nanosleep+0x35b/0x3b0 kernel/time/posix-timers.c:1383
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0x174/0x580 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-executor/5620:
 #0: ffff8880b863b160 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xb2/0x160 kernel/sched/core.c:675
 #1: ffffffff8eb4bfa0 (console_lock){+.+.}-{0:0}, at: _printk+0xdd/0x130 kernel/printk/printk.c:2504
 #2: ffffffff8ea33838 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:305 [inline]
 #2: ffffffff8ea33838 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:428 [inline]
 #2: ffffffff8ea33838 (console_srcu){....}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:291 [inline]
 #2: ffffffff8ea33838 (console_srcu){....}-{0:0}, at: console_flush_one_record kernel/printk/printk.c:3246 [inline]
 #2: ffffffff8ea33838 (console_srcu){....}-{0:0}, at: console_flush_all+0x123/0xaf0 kernel/printk/printk.c:3343

stack backtrace:
CPU: 0 UID: 0 PID: 5620 Comm: syz-executor 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_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_circular_bug+0x2e1/0x300 kernel/locking/lockdep.c:2043
 check_noncircular+0x12e/0x150 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+0x1520/0x2cf0 kernel/locking/lockdep.c:5237
 lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
 console_lock_spinning_enable kernel/printk/printk.c:1902 [inline]
 console_emit_next_record kernel/printk/printk.c:3177 [inline]
 console_flush_one_record kernel/printk/printk.c:3269 [inline]
 console_flush_all+0x693/0xaf0 kernel/printk/printk.c:3343
 __console_flush_and_unlock kernel/printk/printk.c:3373 [inline]
 console_unlock+0xd1/0x1c0 kernel/printk/printk.c:3413
 vprintk_emit+0x485/0x560 kernel/printk/printk.c:2479
 _printk+0xdd/0x130 kernel/printk/printk.c:2504
 __report_bug+0x349/0x570 lib/bug.c:248
 report_bug+0x16a/0x220 lib/bug.c:286
 handle_bug+0x9c/0x200 arch/x86/kernel/traps.c:436
 exc_invalid_op+0x1a/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:update_rq_clock+0x34d/0x560 kernel/sched/core.c:865
Code: 48 c1 e8 03 80 3c 28 00 74 08 48 89 df e8 5b 1b a0 00 4c 01 3b 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f 5d e9 60 ae 7b ff cc 90 <0f> 0b 90 e9 42 fd ff ff 48 89 df 48 83 c4 10 5b 41 5c 41 5d 41 5e
RSP: 0018:ffffc90004007998 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffff8880b873b100 RCX: 0000000080000002
RDX: ffffffffffffffff RSI: ffffffff8e4b411b RDI: ffffffff8c4bdd80
RBP: dffffc0000000000 R08: ffffc90004007b68 R09: 1ffffffff20af3a6
R10: dffffc0000000000 R11: ffffffff8197ced0 R12: ffff88807f64a6e0
R13: dffffc0000000001 R14: ffff8880b873bfc8 R15: ffff8880b873b100
 pick_next_task kernel/sched/core.c:6338 [inline]
 __schedule+0x388e/0x56c0 kernel/sched/core.c:7149
 __schedule_loop kernel/sched/core.c:7311 [inline]
 schedule+0x164/0x2b0 kernel/sched/core.c:7326
 do_nanosleep+0x21e/0x6a0 kernel/time/hrtimer.c:2399
 hrtimer_nanosleep+0x18f/0x3a0 kernel/time/hrtimer.c:2445
 __do_sys_clock_nanosleep kernel/time/posix-timers.c:1406 [inline]
 __se_sys_clock_nanosleep+0x35b/0x3b0 kernel/time/posix-timers.c:1383
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fdff915e84e
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:00007ffc261df4e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e6
RAX: ffffffffffffffda RBX: 0000555566d12500 RCX: 00007fdff915e84e
RDX: 00007ffc261df540 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ffc261df5ac R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000001388
R13: 00000000000927c0 R14: 000000000003a229 R15: 00007ffc261df600
 </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-executor/5620
WARNING: kernel/sched/sched.h:1641 at update_rq_clock+0x34d/0x560 kernel/sched/core.c:865, CPU#0: syz-executor/5620
Modules linked in:
CPU: 0 UID: 0 PID: 5620 Comm: syz-executor 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:update_rq_clock+0x34d/0x560 kernel/sched/core.c:865
Code: 48 c1 e8 03 80 3c 28 00 74 08 48 89 df e8 5b 1b a0 00 4c 01 3b 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f 5d e9 60 ae 7b ff cc 90 <0f> 0b 90 e9 42 fd ff ff 48 89 df 48 83 c4 10 5b 41 5c 41 5d 41 5e
RSP: 0018:ffffc90004007998 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffff8880b873b100 RCX: 0000000080000002
RDX: ffffffffffffffff RSI: ffffffff8e4b411b RDI: ffffffff8c4bdd80
RBP: dffffc0000000000 R08: ffffc90004007b68 R09: 1ffffffff20af3a6
R10: dffffc0000000000 R11: ffffffff8197ced0 R12: ffff88807f64a6e0
R13: dffffc0000000001 R14: ffff8880b873bfc8 R15: ffff8880b873b100
FS:  0000555566d12500(0000) GS:ffff888124f4c000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffd6c3b8da0 CR3: 0000000066976000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 pick_next_task kernel/sched/core.c:6338 [inline]
 __schedule+0x388e/0x56c0 kernel/sched/core.c:7149
 __schedule_loop kernel/sched/core.c:7311 [inline]
 schedule+0x164/0x2b0 kernel/sched/core.c:7326
 do_nanosleep+0x21e/0x6a0 kernel/time/hrtimer.c:2399
 hrtimer_nanosleep+0x18f/0x3a0 kernel/time/hrtimer.c:2445
 __do_sys_clock_nanosleep kernel/time/posix-timers.c:1406 [inline]
 __se_sys_clock_nanosleep+0x35b/0x3b0 kernel/time/posix-timers.c:1383
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fdff915e84e
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:00007ffc261df4e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e6
RAX: ffffffffffffffda RBX: 0000555566d12500 RCX: 00007fdff915e84e
RDX: 00007ffc261df540 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ffc261df5ac R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000001388
R13: 00000000000927c0 R14: 000000000003a229 R15: 00007ffc261df600
 </TASK>