Kernel panic - not syncing: kernel: panic_on_warn set ... ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.5.43/6020 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: ffff888029a0a990 (&p->pi_lock){-.-.}-{2:2}, at: task_call_func+0x8b/0x380 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}: 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+0x60/0xe0 arch/x86/kernel/irq.c:273 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:665 -> #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 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:178 [inline] _raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:198 spin_unlock_irqrestore include/linux/spinlock.h:408 [inline] uart_port_unlock_irqrestore include/linux/serial_core.h:790 [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+0x29d/0xb20 drivers/tty/serial/serial_core.c:630 process_output_block drivers/tty/n_tty.c:557 [inline] n_tty_write+0x431/0x1160 drivers/tty/n_tty.c:2366 iterate_tty_write drivers/tty/tty_io.c:1006 [inline] file_tty_write.isra.0+0x4d2/0x890 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+0xd4/0x120 drivers/tty/tty_io.c:1105 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x6ac/0x1050 fs/read_write.c:687 ksys_write+0x12a/0x250 fs/read_write.c:739 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 -> #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 vpanic+0x45c/0x970 kernel/panic.c:640 panic+0xd1/0xe0 kernel/panic.c:788 check_panic_on_warn kernel/panic.c:525 [inline] check_panic_on_warn.cold+0x19/0x34 kernel/panic.c:520 __warn.cold+0x191/0x318 kernel/panic.c:1104 __report_bug+0x30f/0x440 lib/bug.c:254 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 __set_task_frozen+0x211/0x2e0 kernel/freezer.c:139 task_call_func+0x169/0x380 kernel/sched/core.c:4495 __freeze_task kernel/freezer.c:150 [inline] freeze_task+0x151/0x270 kernel/freezer.c:169 try_to_freeze_tasks+0x243/0x680 kernel/power/process.c:54 freeze_processes+0xf2/0x1f0 kernel/power/process.c:137 suspend_freeze_processes kernel/power/power.h:281 [inline] suspend_prepare kernel/power/suspend.c:387 [inline] enter_state kernel/power/suspend.c:609 [inline] pm_suspend kernel/power/suspend.c:644 [inline] pm_suspend+0x32c/0x7b0 kernel/power/suspend.c:636 state_store+0x101/0x240 kernel/power/main.c:819 kobj_attr_store+0x58/0x80 lib/kobject.c:840 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:145 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:345 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x6ac/0x1050 fs/read_write.c:687 ksys_write+0x12a/0x250 fs/read_write.c:739 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 --> &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.5.43/6020: #0: ffff88802ef19270 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2aa/0x380 fs/file.c:1259 #1: ffff888051fac450 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739 #2: ffff88806a5ac080 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:336 #3: ffff8880202a1968 (kn->active#70){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline] #3: ffff8880202a1968 (kn->active#70){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x332/0x5f0 fs/kernfs/file.c:337 #4: ffffffff8ea9fc80 (system_transition_mutex){+.+.}-{4:4}, at: enter_state kernel/power/suspend.c:591 [inline] #4: ffffffff8ea9fc80 (system_transition_mutex){+.+.}-{4:4}, at: pm_suspend kernel/power/suspend.c:644 [inline] #4: ffffffff8ea9fc80 (system_transition_mutex){+.+.}-{4:4}, at: pm_suspend+0x586/0x7b0 kernel/power/suspend.c:636 #5: ffffffff8e80a098 (tasklist_lock){.+.+}-{3:3}, at: try_to_freeze_tasks+0x148/0x680 kernel/power/process.c:52 #6: ffffffff8ec181f8 (freezer_lock){....}-{3:3}, at: freeze_task+0x71/0x270 kernel/freezer.c:168 #7: ffff888029a0a990 (&p->pi_lock){-.-.}-{2:2}, at: task_call_func+0x8b/0x380 kernel/sched/core.c:4476 #8: ffffffff8ebd45a0 (console_lock){+.+.}-{0:0}, at: _printk+0xcf/0x110 kernel/printk/printk.c:2504 #9: ffffffff8ebd4618 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:305 [inline] #9: ffffffff8ebd4618 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:428 [inline] #9: ffffffff8ebd4618 (console_srcu){....}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:291 [inline] #9: ffffffff8ebd4618 (console_srcu){....}-{0:0}, at: console_flush_one_record+0xfd/0xe50 kernel/printk/printk.c:3246 stack backtrace: CPU: 1 UID: 0 PID: 6020 Comm: syz.5.43 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 Call Trace: __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 vpanic+0x45c/0x970 kernel/panic.c:640 panic+0xd1/0xe0 kernel/panic.c:788 check_panic_on_warn kernel/panic.c:525 [inline] check_panic_on_warn.cold+0x19/0x34 kernel/panic.c:520 __warn.cold+0x191/0x318 kernel/panic.c:1104 __report_bug+0x30f/0x440 lib/bug.c:254 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:__set_task_frozen+0x211/0x2e0 kernel/freezer.c:139 Code: 0f b6 04 02 84 c0 74 09 3c 03 7f 05 e8 18 9a 85 00 8b ab 98 0b 00 00 31 ff 89 ee e8 29 02 16 00 85 ed 74 09 e8 b0 07 16 00 90 <0f> 0b 90 e8 a7 07 16 00 4c 89 e2 48 b8 00 00 00 00 00 fc ff df 48 RSP: 0018:ffffc9000557f990 EFLAGS: 00010046 RAX: 0000000000080000 RBX: ffff888029a09f00 RCX: ffffc900062e1000 RDX: 0000000000080000 RSI: ffffffff81f44c10 RDI: ffff88802a9abe00 RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000003 R11: 0000000000000000 R12: ffff888029a09f18 R13: 0000000000000002 R14: dffffc0000000000 R15: ffff888029a0a978 task_call_func+0x169/0x380 kernel/sched/core.c:4495 __freeze_task kernel/freezer.c:150 [inline] freeze_task+0x151/0x270 kernel/freezer.c:169 try_to_freeze_tasks+0x243/0x680 kernel/power/process.c:54 freeze_processes+0xf2/0x1f0 kernel/power/process.c:137 suspend_freeze_processes kernel/power/power.h:281 [inline] suspend_prepare kernel/power/suspend.c:387 [inline] enter_state kernel/power/suspend.c:609 [inline] pm_suspend kernel/power/suspend.c:644 [inline] pm_suspend+0x32c/0x7b0 kernel/power/suspend.c:636 state_store+0x101/0x240 kernel/power/main.c:819 kobj_attr_store+0x58/0x80 lib/kobject.c:840 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:145 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:345 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x6ac/0x1050 fs/read_write.c:687 ksys_write+0x12a/0x250 fs/read_write.c:739 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: 0033:0x7fd7fb79e019 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:00007fd7fc58e028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fd7fba25fa0 RCX: 00007fd7fb79e019 RDX: 0000000000000005 RSI: 0000200000000200 RDI: 0000000000000004 RBP: 00007fd7fb83500c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fd7fba26038 R14: 00007fd7fba25fa0 R15: 00007ffd9e02dce8 CPU: 1 UID: 0 PID: 6020 Comm: syz.5.43 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 vpanic+0x552/0x970 kernel/panic.c:651 panic+0xd1/0xe0 kernel/panic.c:788 check_panic_on_warn kernel/panic.c:525 [inline] check_panic_on_warn.cold+0x19/0x34 kernel/panic.c:520 __warn.cold+0x191/0x318 kernel/panic.c:1104 __report_bug+0x30f/0x440 lib/bug.c:254 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:__set_task_frozen+0x211/0x2e0 kernel/freezer.c:139 Code: 0f b6 04 02 84 c0 74 09 3c 03 7f 05 e8 18 9a 85 00 8b ab 98 0b 00 00 31 ff 89 ee e8 29 02 16 00 85 ed 74 09 e8 b0 07 16 00 90 <0f> 0b 90 e8 a7 07 16 00 4c 89 e2 48 b8 00 00 00 00 00 fc ff df 48 RSP: 0018:ffffc9000557f990 EFLAGS: 00010046 RAX: 0000000000080000 RBX: ffff888029a09f00 RCX: ffffc900062e1000 RDX: 0000000000080000 RSI: ffffffff81f44c10 RDI: ffff88802a9abe00 RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000003 R11: 0000000000000000 R12: ffff888029a09f18 R13: 0000000000000002 R14: dffffc0000000000 R15: ffff888029a0a978 task_call_func+0x169/0x380 kernel/sched/core.c:4495 __freeze_task kernel/freezer.c:150 [inline] freeze_task+0x151/0x270 kernel/freezer.c:169 try_to_freeze_tasks+0x243/0x680 kernel/power/process.c:54 freeze_processes+0xf2/0x1f0 kernel/power/process.c:137 suspend_freeze_processes kernel/power/power.h:281 [inline] suspend_prepare kernel/power/suspend.c:387 [inline] enter_state kernel/power/suspend.c:609 [inline] pm_suspend kernel/power/suspend.c:644 [inline] pm_suspend+0x32c/0x7b0 kernel/power/suspend.c:636 state_store+0x101/0x240 kernel/power/main.c:819 kobj_attr_store+0x58/0x80 lib/kobject.c:840 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:145 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:345 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x6ac/0x1050 fs/read_write.c:687 ksys_write+0x12a/0x250 fs/read_write.c:739 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: 0033:0x7fd7fb79e019 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:00007fd7fc58e028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fd7fba25fa0 RCX: 00007fd7fb79e019 RDX: 0000000000000005 RSI: 0000200000000200 RDI: 0000000000000004 RBP: 00007fd7fb83500c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fd7fba26038 R14: 00007fd7fba25fa0 R15: 00007ffd9e02dce8 Shutting down cpus with NMI Kernel Offset: disabled Rebooting in 86400 seconds..