Kernel panic - not syncing: kernel: panic_on_warn set ...

======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.1.412/8666 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:
ffff888026b0c890 (&p->pi_lock){-.-.}-{2:2}, at: task_call_func+0x42/0x260 kernel/sched/core.c:4476

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (&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
       __wake_up_common kernel/sched/wait.c:108 [inline]
       __wake_up_common_lock+0x13a/0x1f0 kernel/sched/wait.c:125
       tty_port_default_wakeup+0xc8/0x100 drivers/tty/tty_port.c:67
       serial8250_tx_chars+0x70e/0x950 drivers/tty/serial/8250/8250_port.c:1723
       serial8250_handle_irq+0x166/0x550 drivers/tty/serial/8250/8250_port.c:1853
       serial8250_default_handle_irq+0xbf/0x1e0 drivers/tty/serial/8250/8250_port.c:1867
       serial8250_interrupt+0x8d/0x160 drivers/tty/serial/8250/8250_core.c:86
       __handle_irq_event_percpu+0x216/0x9a0 kernel/irq/handle.c:209
       handle_irq_event_percpu kernel/irq/handle.c:246 [inline]
       handle_irq_event+0x8b/0x1e0 kernel/irq/handle.c:263
       handle_edge_irq+0x1f4/0x8a0 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:-1 [inline]
       __common_interrupt+0x141/0x1f0 arch/x86/kernel/irq.c:280
       common_interrupt+0xb6/0xe0 arch/x86/kernel/irq.c:273
       asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:665
       deref_stack_reg arch/x86/kernel/unwind_orc.c:422 [inline]
       unwind_next_frame+0xca8/0x2550 arch/x86/kernel/unwind_orc.c:614
       arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
       stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
       save_stack+0x122/0x230 mm/page_owner.c:165
       __reset_page_owner+0x71/0x1f0 mm/page_owner.c:320
       reset_page_owner include/linux/page_owner.h:25 [inline]
       __free_pages_prepare mm/page_alloc.c:1406 [inline]
       free_unref_folios+0xd84/0x14a0 mm/page_alloc.c:3011
       folio_batch_move_lru+0x877/0xa60 mm/swap.c:211
       __folio_batch_add_and_move+0x510/0xc50 mm/swap.c:231
       folio_add_lru_vma+0x196/0x210 mm/swap.c:581
       wp_page_copy mm/memory.c:3943 [inline]
       do_wp_page+0x3d96/0x4c70 mm/memory.c:4336
       handle_pte_fault mm/memory.c:6395 [inline]
       __handle_mm_fault mm/memory.c:6517 [inline]
       handle_mm_fault+0x1490/0x3080 mm/memory.c:6686
       do_user_addr_fault+0xa4d/0x1340 arch/x86/mm/fault.c:1343
       handle_page_fault arch/x86/mm/fault.c:1483 [inline]
       exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1536
       asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:595

-> #2 (&tty->write_wait){-.-.}-{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
       __wake_up_common_lock+0x30/0x1f0 kernel/sched/wait.c:124
       tty_port_default_wakeup+0xc8/0x100 drivers/tty/tty_port.c:67
       serial8250_tx_chars+0x70e/0x950 drivers/tty/serial/8250/8250_port.c:1723
       serial8250_handle_irq+0x166/0x550 drivers/tty/serial/8250/8250_port.c:1853
       serial8250_default_handle_irq+0xbf/0x1e0 drivers/tty/serial/8250/8250_port.c:1867
       serial8250_interrupt+0x8d/0x160 drivers/tty/serial/8250/8250_core.c:86
       __handle_irq_event_percpu+0x216/0x9a0 kernel/irq/handle.c:209
       handle_irq_event_percpu kernel/irq/handle.c:246 [inline]
       handle_irq_event+0x8b/0x1e0 kernel/irq/handle.c:263
       handle_edge_irq+0x1f4/0x8a0 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:-1 [inline]
       __common_interrupt+0x141/0x1f0 arch/x86/kernel/irq.c:280
       common_interrupt+0xb6/0xe0 arch/x86/kernel/irq.c:273
       asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:665
       native_irq_enable arch/x86/include/asm/irqflags.h:42 [inline]
       arch_local_irq_enable arch/x86/include/asm/irqflags.h:119 [inline]
       raw_spin_rq_unlock_irq kernel/sched/sched.h:1673 [inline]
       finish_lock_switch kernel/sched/core.c:5241 [inline]
       finish_task_switch+0x417/0xc60 kernel/sched/core.c:5359
       context_switch kernel/sched/core.c:5513 [inline]
       __schedule+0x17e1/0x56c0 kernel/sched/core.c:7234
       __schedule_loop kernel/sched/core.c:7311 [inline]
       schedule+0x164/0x2b0 kernel/sched/core.c:7326
       worker_thread+0xc12/0xfb0 kernel/workqueue.c:3501
       kthread+0x388/0x470 kernel/kthread.c:436
       ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #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
       vpanic+0x476/0xa60 kernel/panic.c:640
       panic+0xc5/0xd0 kernel/panic.c:788
       check_panic_on_warn kernel/panic.c:525 [inline]
       __warn+0x315/0x4c0 kernel/panic.c:1104
       __report_bug+0x276/0x570 lib/bug.c:254
       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
       __set_task_frozen+0x260/0x340 kernel/freezer.c:139
       task_call_func+0x1aa/0x260 kernel/sched/core.c:4495
       __freeze_task kernel/freezer.c:150 [inline]
       freeze_task+0x229/0x3b0 kernel/freezer.c:169
       try_to_freeze_tasks+0x190/0x620 kernel/power/process.c:54
       freeze_processes+0xce/0x1e0 kernel/power/process.c:137
       hibernate+0x247/0x680 kernel/power/hibernate.c:801
       state_store+0x234/0x290 kernel/power/main.c:821
       kernfs_fop_write_iter+0x3a4/0x540 fs/kernfs/file.c:345
       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

other info that might help us debug this:

Chain exists of:
  console_owner --> &tty->write_wait --> &p->pi_lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&p->pi_lock);
                               lock(&tty->write_wait);
                               lock(&p->pi_lock);
  lock(console_owner);

 *** DEADLOCK ***

10 locks held by syz.1.412/8666:
 #0: ffff88803b86f270 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320 fs/file.c:1259
 #1: ffff88803c234450 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline]
 #1: ffff88803c234450 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683
 #2: ffff888067737c80 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d8/0x540 fs/kernfs/file.c:336
 #3: ffff88801f28d968 (kn->active#61){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
 #3: ffff88801f28d968 (kn->active#61){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22b/0x540 fs/kernfs/file.c:337
 #4: ffffffff8ea02160 (system_transition_mutex){+.+.}-{4:4}, at: lock_system_sleep+0x49/0x70 kernel/power/main.c:71
 #5: ffffffff8e80a058 (tasklist_lock){.+.+}-{3:3}, at: try_to_freeze_tasks+0xe5/0x620 kernel/power/process.c:52
 #6: ffffffff8eb7b7b8 (freezer_lock){....}-{3:3}, at: freeze_task+0x7e/0x3b0 kernel/freezer.c:168
 #7: ffff888026b0c890 (&p->pi_lock){-.-.}-{2:2}, at: task_call_func+0x42/0x260 kernel/sched/core.c:4476
 #8: ffffffff8eb4bfa0 (console_lock){+.+.}-{0:0}, at: _printk+0xdd/0x130 kernel/printk/printk.c:2504
 #9: ffffffff8ea33838 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:305 [inline]
 #9: ffffffff8ea33838 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:428 [inline]
 #9: ffffffff8ea33838 (console_srcu){....}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:291 [inline]
 #9: ffffffff8ea33838 (console_srcu){....}-{0:0}, at: console_flush_one_record kernel/printk/printk.c:3246 [inline]
 #9: ffffffff8ea33838 (console_srcu){....}-{0:0}, at: console_flush_all+0x123/0xaf0 kernel/printk/printk.c:3343

stack backtrace:
CPU: 0 UID: 0 PID: 8666 Comm: syz.1.412 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Call Trace:
 <TASK>
 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
 vpanic+0x476/0xa60 kernel/panic.c:640
 panic+0xc5/0xd0 kernel/panic.c:788
 check_panic_on_warn kernel/panic.c:525 [inline]
 __warn+0x315/0x4c0 kernel/panic.c:1104
 __report_bug+0x276/0x570 lib/bug.c:254
 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:__set_task_frozen+0x260/0x340 kernel/freezer.c:139
Code: 00 80 00 00 89 e8 5b 41 5c 41 5d 41 5e 41 5f 5d e9 20 43 5e ff cc e8 7f 14 15 00 90 0f 0b 90 e9 f7 fe ff ff e8 71 14 15 00 90 <0f> 0b 90 eb 93 44 89 e1 80 e1 07 80 c1 03 38 c1 0f 8c c3 fd ff ff
RSP: 0018:ffffc90003dcfa10 EFLAGS: 00010083
RAX: ffffffff81b1fdff RBX: ffff888026b0be00 RCX: 0000000000080000
RDX: ffffc9001ebd8000 RSI: 0000000000025ae2 RDI: 0000000000025ae3
RBP: 0000000000000003 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: ffffffff81b1fba0 R12: ffff888026b0be18
R13: 1ffff11004d617c3 R14: 0000000000000000 R15: ffff888026b0c998
 task_call_func+0x1aa/0x260 kernel/sched/core.c:4495
 __freeze_task kernel/freezer.c:150 [inline]
 freeze_task+0x229/0x3b0 kernel/freezer.c:169
 try_to_freeze_tasks+0x190/0x620 kernel/power/process.c:54
 freeze_processes+0xce/0x1e0 kernel/power/process.c:137
 hibernate+0x247/0x680 kernel/power/hibernate.c:801
 state_store+0x234/0x290 kernel/power/main.c:821
 kernfs_fop_write_iter+0x3a4/0x540 fs/kernfs/file.c:345
 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
RIP: 0033:0x7fecbe39e019
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fecbf2e7028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fecbe625fa0 RCX: 00007fecbe39e019
RDX: 0000000000000005 RSI: 0000200000000240 RDI: 0000000000000006
RBP: 00007fecbe43500c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fecbe626038 R14: 00007fecbe625fa0 R15: 00007fffa01e45d8
 </TASK>
CPU: 0 UID: 0 PID: 8666 Comm: syz.1.412 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Call Trace:
 <TASK>
 vpanic+0x56c/0xa60 kernel/panic.c:651
 panic+0xc5/0xd0 kernel/panic.c:788
 check_panic_on_warn kernel/panic.c:525 [inline]
 __warn+0x315/0x4c0 kernel/panic.c:1104
 __report_bug+0x276/0x570 lib/bug.c:254
 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:__set_task_frozen+0x260/0x340 kernel/freezer.c:139
Code: 00 80 00 00 89 e8 5b 41 5c 41 5d 41 5e 41 5f 5d e9 20 43 5e ff cc e8 7f 14 15 00 90 0f 0b 90 e9 f7 fe ff ff e8 71 14 15 00 90 <0f> 0b 90 eb 93 44 89 e1 80 e1 07 80 c1 03 38 c1 0f 8c c3 fd ff ff
RSP: 0018:ffffc90003dcfa10 EFLAGS: 00010083
RAX: ffffffff81b1fdff RBX: ffff888026b0be00 RCX: 0000000000080000
RDX: ffffc9001ebd8000 RSI: 0000000000025ae2 RDI: 0000000000025ae3
RBP: 0000000000000003 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: ffffffff81b1fba0 R12: ffff888026b0be18
R13: 1ffff11004d617c3 R14: 0000000000000000 R15: ffff888026b0c998
 task_call_func+0x1aa/0x260 kernel/sched/core.c:4495
 __freeze_task kernel/freezer.c:150 [inline]
 freeze_task+0x229/0x3b0 kernel/freezer.c:169
 try_to_freeze_tasks+0x190/0x620 kernel/power/process.c:54
 freeze_processes+0xce/0x1e0 kernel/power/process.c:137
 hibernate+0x247/0x680 kernel/power/hibernate.c:801
 state_store+0x234/0x290 kernel/power/main.c:821
 kernfs_fop_write_iter+0x3a4/0x540 fs/kernfs/file.c:345
 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
RIP: 0033:0x7fecbe39e019
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fecbf2e7028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fecbe625fa0 RCX: 00007fecbe39e019
RDX: 0000000000000005 RSI: 0000200000000240 RDI: 0000000000000006
RBP: 00007fecbe43500c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fecbe626038 R14: 00007fecbe625fa0 R15: 00007fffa01e45d8
 </TASK>
Kernel Offset: disabled
Rebooting in 86400 seconds..