===================================================== WARNING: HARDIRQ-safe -> HARDIRQ-unsafe lock order detected 6.10.0-rc7-syzkaller-00025-ga19ea421490d #0 Not tainted ----------------------------------------------------- kworker/u8:1/13815 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire: ffffffff8ee2e4b8 (disc_data_lock#3){.+.+}-{2:2}, at: sp_get drivers/net/hamradio/6pack.c:376 [inline] ffffffff8ee2e4b8 (disc_data_lock#3){.+.+}-{2:2}, at: sixpack_write_wakeup+0x30/0x430 drivers/net/hamradio/6pack.c:397 and this task is already holding: ffffffff94a977b8 (&port_lock_key){-.-.}-{2:2}, at: uart_port_lock_irqsave include/linux/serial_core.h:618 [inline] ffffffff94a977b8 (&port_lock_key){-.-.}-{2:2}, at: uart_write+0x10a/0x380 drivers/tty/serial/serial_core.c:624 which would create a new lock dependency: (&port_lock_key){-.-.}-{2:2} -> (disc_data_lock#3){.+.+}-{2:2} but this new dependency connects a HARDIRQ-irq-safe lock: (&port_lock_key){-.-.}-{2:2} ... which became HARDIRQ-irq-safe at: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162 uart_port_lock_irqsave include/linux/serial_core.h:618 [inline] serial8250_handle_irq+0x81/0x710 drivers/tty/serial/8250/8250_port.c:1900 serial8250_default_handle_irq+0xd1/0x1f0 drivers/tty/serial/8250/8250_port.c:1949 serial8250_interrupt+0xa9/0x1f0 drivers/tty/serial/8250/8250_core.c:127 __handle_irq_event_percpu+0x29a/0xa80 kernel/irq/handle.c:158 handle_irq_event_percpu kernel/irq/handle.c:193 [inline] handle_irq_event+0x89/0x1f0 kernel/irq/handle.c:210 handle_edge_irq+0x25f/0xc20 kernel/irq/chip.c:831 generic_handle_irq_desc include/linux/irqdesc.h:173 [inline] handle_irq arch/x86/kernel/irq.c:247 [inline] call_irq_handler arch/x86/kernel/irq.c:259 [inline] __common_interrupt+0x136/0x230 arch/x86/kernel/irq.c:285 common_interrupt+0xa5/0xd0 arch/x86/kernel/irq.c:278 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock_irqrestore+0xd8/0x140 kernel/locking/spinlock.c:194 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] uart_port_unlock_irqrestore include/linux/serial_core.h:669 [inline] uart_write+0x15d/0x380 drivers/tty/serial/serial_core.c:634 process_output_block drivers/tty/n_tty.c:574 [inline] n_tty_write+0xd6a/0x1230 drivers/tty/n_tty.c:2389 iterate_tty_write drivers/tty/tty_io.c:1021 [inline] file_tty_write+0x54f/0x9b0 drivers/tty/tty_io.c:1096 new_sync_write fs/read_write.c:497 [inline] vfs_write+0xa72/0xc90 fs/read_write.c:590 ksys_write+0x1a0/0x2c0 fs/read_write.c:643 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f to a HARDIRQ-irq-unsafe lock: (disc_data_lock#3){.+.+}-{2:2} ... which became HARDIRQ-irq-unsafe at: ... lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 __raw_read_lock include/linux/rwlock_api_smp.h:150 [inline] _raw_read_lock+0x36/0x50 kernel/locking/spinlock.c:228 sp_get drivers/net/hamradio/6pack.c:376 [inline] sixpack_receive_buf+0x56/0x1380 drivers/net/hamradio/6pack.c:439 tty_ldisc_receive_buf+0x11f/0x170 drivers/tty/tty_buffer.c:391 tty_port_default_receive_buf+0x6d/0xa0 drivers/tty/tty_port.c:37 receive_buf drivers/tty/tty_buffer.c:445 [inline] flush_to_ldisc+0x328/0x860 drivers/tty/tty_buffer.c:495 process_one_work kernel/workqueue.c:3248 [inline] process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3329 worker_thread+0x86d/0xd50 kernel/workqueue.c:3409 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 other info that might help us debug this: Possible interrupt unsafe locking scenario: CPU0 CPU1 ---- ---- lock(disc_data_lock#3); local_irq_disable(); lock(&port_lock_key); lock(disc_data_lock#3); lock(&port_lock_key); *** DEADLOCK *** 6 locks held by kworker/u8:1/13815: #0: ffff888015089148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3223 [inline] #0: ffff888015089148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x90a/0x1830 kernel/workqueue.c:3329 #1: ffffc9000930fd00 ((work_completion)(&buf->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3224 [inline] #1: ffffc9000930fd00 ((work_completion)(&buf->work)){+.+.}-{0:0}, at: process_scheduled_works+0x945/0x1830 kernel/workqueue.c:3329 #2: ffff88801fe80ca0 (&buf->lock){+.+.}-{3:3}, at: flush_to_ldisc+0x38/0x860 drivers/tty/tty_buffer.c:467 #3: ffff8880288f00a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref+0x1c/0x80 drivers/tty/tty_ldisc.c:263 #4: ffffffff94a977b8 (&port_lock_key){-.-.}-{2:2}, at: uart_port_lock_irqsave include/linux/serial_core.h:618 [inline] #4: ffffffff94a977b8 (&port_lock_key){-.-.}-{2:2}, at: uart_write+0x10a/0x380 drivers/tty/serial/serial_core.c:624 #5: ffff8880288f00a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref+0x1c/0x80 drivers/tty/tty_ldisc.c:263 the dependencies between HARDIRQ-irq-safe lock and the holding lock: -> (&port_lock_key){-.-.}-{2:2} { IN-HARDIRQ-W at: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162 uart_port_lock_irqsave include/linux/serial_core.h:618 [inline] serial8250_handle_irq+0x81/0x710 drivers/tty/serial/8250/8250_port.c:1900 serial8250_default_handle_irq+0xd1/0x1f0 drivers/tty/serial/8250/8250_port.c:1949 serial8250_interrupt+0xa9/0x1f0 drivers/tty/serial/8250/8250_core.c:127 __handle_irq_event_percpu+0x29a/0xa80 kernel/irq/handle.c:158 handle_irq_event_percpu kernel/irq/handle.c:193 [inline] handle_irq_event+0x89/0x1f0 kernel/irq/handle.c:210 handle_edge_irq+0x25f/0xc20 kernel/irq/chip.c:831 generic_handle_irq_desc include/linux/irqdesc.h:173 [inline] handle_irq arch/x86/kernel/irq.c:247 [inline] call_irq_handler arch/x86/kernel/irq.c:259 [inline] __common_interrupt+0x136/0x230 arch/x86/kernel/irq.c:285 common_interrupt+0xa5/0xd0 arch/x86/kernel/irq.c:278 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock_irqrestore+0xd8/0x140 kernel/locking/spinlock.c:194 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] uart_port_unlock_irqrestore include/linux/serial_core.h:669 [inline] uart_write+0x15d/0x380 drivers/tty/serial/serial_core.c:634 process_output_block drivers/tty/n_tty.c:574 [inline] n_tty_write+0xd6a/0x1230 drivers/tty/n_tty.c:2389 iterate_tty_write drivers/tty/tty_io.c:1021 [inline] file_tty_write+0x54f/0x9b0 drivers/tty/tty_io.c:1096 new_sync_write fs/read_write.c:497 [inline] vfs_write+0xa72/0xc90 fs/read_write.c:590 ksys_write+0x1a0/0x2c0 fs/read_write.c:643 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f IN-SOFTIRQ-W at: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162 uart_port_lock_irqsave include/linux/serial_core.h:618 [inline] serial8250_handle_irq+0x81/0x710 drivers/tty/serial/8250/8250_port.c:1900 serial8250_default_handle_irq+0xd1/0x1f0 drivers/tty/serial/8250/8250_port.c:1949 serial8250_interrupt+0xa9/0x1f0 drivers/tty/serial/8250/8250_core.c:127 __handle_irq_event_percpu+0x29a/0xa80 kernel/irq/handle.c:158 handle_irq_event_percpu kernel/irq/handle.c:193 [inline] handle_irq_event+0x89/0x1f0 kernel/irq/handle.c:210 handle_edge_irq+0x25f/0xc20 kernel/irq/chip.c:831 generic_handle_irq_desc include/linux/irqdesc.h:173 [inline] handle_irq arch/x86/kernel/irq.c:247 [inline] call_irq_handler arch/x86/kernel/irq.c:259 [inline] __common_interrupt+0x136/0x230 arch/x86/kernel/irq.c:285 common_interrupt+0x4f/0xd0 arch/x86/kernel/irq.c:278 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693 smt_balance kernel/sched/fair.c:9880 [inline] update_sg_lb_stats kernel/sched/fair.c:10014 [inline] update_sd_lb_stats kernel/sched/fair.c:10637 [inline] sched_balance_find_src_group kernel/sched/fair.c:10896 [inline] sched_balance_rq+0x1b8e/0x8780 kernel/sched/fair.c:11336 sched_balance_domains+0x565/0xa90 kernel/sched/fair.c:11798 handle_softirqs+0x2c4/0x970 kernel/softirq.c:554 __do_softirq kernel/softirq.c:588 [inline] invoke_softirq kernel/softirq.c:428 [inline] __irq_exit_rcu+0xf4/0x1c0 kernel/softirq.c:637 irq_exit_rcu+0x9/0x30 kernel/softirq.c:649 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1043 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline] arch_safe_halt arch/x86/include/asm/irqflags.h:86 [inline] acpi_safe_halt+0x21/0x30 drivers/acpi/processor_idle.c:111 acpi_idle_enter+0xe4/0x140 drivers/acpi/processor_idle.c:702 cpuidle_enter_state+0x112/0x480 drivers/cpuidle/cpuidle.c:267 cpuidle_enter+0x5d/0xa0 drivers/cpuidle/cpuidle.c:388 call_cpuidle kernel/sched/idle.c:155 [inline] cpuidle_idle_call kernel/sched/idle.c:236 [inline] do_idle+0x375/0x5d0 kernel/sched/idle.c:332 cpu_startup_entry+0x42/0x60 kernel/sched/idle.c:430 __pfx_ap_starting+0x0/0x10 arch/x86/kernel/smpboot.c:313 common_startup_64+0x13e/0x147 INITIAL USE at: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162 uart_port_lock_irqsave include/linux/serial_core.h:618 [inline] serial8250_do_set_termios+0x4c2/0x1720 drivers/tty/serial/8250/8250_port.c:2742 uart_set_options+0x3eb/0x730 drivers/tty/serial/serial_core.c:2330 serial8250_console_setup+0x3db/0x670 drivers/tty/serial/8250/8250_port.c:3456 univ8250_console_setup+0x3ac/0x470 drivers/tty/serial/8250/8250_core.c:629 console_call_setup kernel/printk/printk.c:3299 [inline] try_enable_preferred_console+0x409/0x560 kernel/printk/printk.c:3340 register_console+0x261/0xcf0 kernel/printk/printk.c:3518 univ8250_console_init+0x49/0x50 drivers/tty/serial/8250/8250_core.c:714 console_init+0x1b8/0x6f0 kernel/printk/printk.c:3727 start_kernel+0x2d3/0x500 init/main.c:1038 x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:507 x86_64_start_kernel+0x99/0xa0 arch/x86/kernel/head64.c:488 common_startup_64+0x13e/0x147 } ... key at: [] port_lock_key+0x0/0x20 the dependencies between the lock to be acquired and HARDIRQ-irq-unsafe lock: -> (disc_data_lock#3){.+.+}-{2:2} { HARDIRQ-ON-R at: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 __raw_read_lock include/linux/rwlock_api_smp.h:150 [inline] _raw_read_lock+0x36/0x50 kernel/locking/spinlock.c:228 sp_get drivers/net/hamradio/6pack.c:376 [inline] sixpack_receive_buf+0x56/0x1380 drivers/net/hamradio/6pack.c:439 tty_ldisc_receive_buf+0x11f/0x170 drivers/tty/tty_buffer.c:391 tty_port_default_receive_buf+0x6d/0xa0 drivers/tty/tty_port.c:37 receive_buf drivers/tty/tty_buffer.c:445 [inline] flush_to_ldisc+0x328/0x860 drivers/tty/tty_buffer.c:495 process_one_work kernel/workqueue.c:3248 [inline] process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3329 worker_thread+0x86d/0xd50 kernel/workqueue.c:3409 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 SOFTIRQ-ON-R at: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 __raw_read_lock include/linux/rwlock_api_smp.h:150 [inline] _raw_read_lock+0x36/0x50 kernel/locking/spinlock.c:228 sp_get drivers/net/hamradio/6pack.c:376 [inline] sixpack_receive_buf+0x56/0x1380 drivers/net/hamradio/6pack.c:439 tty_ldisc_receive_buf+0x11f/0x170 drivers/tty/tty_buffer.c:391 tty_port_default_receive_buf+0x6d/0xa0 drivers/tty/tty_port.c:37 receive_buf drivers/tty/tty_buffer.c:445 [inline] flush_to_ldisc+0x328/0x860 drivers/tty/tty_buffer.c:495 process_one_work kernel/workqueue.c:3248 [inline] process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3329 worker_thread+0x86d/0xd50 kernel/workqueue.c:3409 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 INITIAL READ USE at: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 __raw_read_lock include/linux/rwlock_api_smp.h:150 [inline] _raw_read_lock+0x36/0x50 kernel/locking/spinlock.c:228 sp_get drivers/net/hamradio/6pack.c:376 [inline] sixpack_receive_buf+0x56/0x1380 drivers/net/hamradio/6pack.c:439 tty_ldisc_receive_buf+0x11f/0x170 drivers/tty/tty_buffer.c:391 tty_port_default_receive_buf+0x6d/0xa0 drivers/tty/tty_port.c:37 receive_buf drivers/tty/tty_buffer.c:445 [inline] flush_to_ldisc+0x328/0x860 drivers/tty/tty_buffer.c:495 process_one_work kernel/workqueue.c:3248 [inline] process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3329 worker_thread+0x86d/0xd50 kernel/workqueue.c:3409 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 } ... key at: [] disc_data_lock+0x18/0x100 ... acquired at: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 __raw_read_lock include/linux/rwlock_api_smp.h:150 [inline] _raw_read_lock+0x36/0x50 kernel/locking/spinlock.c:228 sp_get drivers/net/hamradio/6pack.c:376 [inline] sixpack_write_wakeup+0x30/0x430 drivers/net/hamradio/6pack.c:397 tty_wakeup+0xbb/0x100 drivers/tty/tty_io.c:523 tty_port_default_wakeup+0xa6/0xf0 drivers/tty/tty_port.c:69 serial8250_tx_chars+0x6e2/0x930 drivers/tty/serial/8250/8250_port.c:1821 __start_tx+0x32e/0x470 drivers/tty/serial/8250/8250_port.c:1527 __uart_start+0x2bc/0x450 drivers/tty/serial/serial_core.c:160 uart_write+0x152/0x380 drivers/tty/serial/serial_core.c:633 decode_prio_command drivers/net/hamradio/6pack.c:888 [inline] sixpack_decode drivers/net/hamradio/6pack.c:963 [inline] sixpack_receive_buf+0x427/0x1380 drivers/net/hamradio/6pack.c:453 tty_ldisc_receive_buf+0x11f/0x170 drivers/tty/tty_buffer.c:391 tty_port_default_receive_buf+0x6d/0xa0 drivers/tty/tty_port.c:37 receive_buf drivers/tty/tty_buffer.c:445 [inline] flush_to_ldisc+0x328/0x860 drivers/tty/tty_buffer.c:495 process_one_work kernel/workqueue.c:3248 [inline] process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3329 worker_thread+0x86d/0xd50 kernel/workqueue.c:3409 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 stack backtrace: CPU: 0 PID: 13815 Comm: kworker/u8:1 Not tainted 6.10.0-rc7-syzkaller-00025-ga19ea421490d #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024 Workqueue: events_unbound flush_to_ldisc Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114 print_bad_irq_dependency kernel/locking/lockdep.c:2626 [inline] check_irq_usage kernel/locking/lockdep.c:2865 [inline] check_prev_add kernel/locking/lockdep.c:3138 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain+0x4de0/0x5900 kernel/locking/lockdep.c:3869 __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 __raw_read_lock include/linux/rwlock_api_smp.h:150 [inline] _raw_read_lock+0x36/0x50 kernel/locking/spinlock.c:228 sp_get drivers/net/hamradio/6pack.c:376 [inline] sixpack_write_wakeup+0x30/0x430 drivers/net/hamradio/6pack.c:397 tty_wakeup+0xbb/0x100 drivers/tty/tty_io.c:523 tty_port_default_wakeup+0xa6/0xf0 drivers/tty/tty_port.c:69 serial8250_tx_chars+0x6e2/0x930 drivers/tty/serial/8250/8250_port.c:1821 __start_tx+0x32e/0x470 drivers/tty/serial/8250/8250_port.c:1527 __uart_start+0x2bc/0x450 drivers/tty/serial/serial_core.c:160 uart_write+0x152/0x380 drivers/tty/serial/serial_core.c:633 decode_prio_command drivers/net/hamradio/6pack.c:888 [inline] sixpack_decode drivers/net/hamradio/6pack.c:963 [inline] sixpack_receive_buf+0x427/0x1380 drivers/net/hamradio/6pack.c:453 tty_ldisc_receive_buf+0x11f/0x170 drivers/tty/tty_buffer.c:391 tty_port_default_receive_buf+0x6d/0xa0 drivers/tty/tty_port.c:37 receive_buf drivers/tty/tty_buffer.c:445 [inline] flush_to_ldisc+0x328/0x860 drivers/tty/tty_buffer.c:495 process_one_work kernel/workqueue.c:3248 [inline] process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3329 worker_thread+0x86d/0xd50 kernel/workqueue.c:3409 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244