===================================================== WARNING: HARDIRQ-safe -> HARDIRQ-unsafe lock order detected 6.8.0-syzkaller-08951-gfe46a7dd189e #0 Not tainted ----------------------------------------------------- kworker/u8:3/50 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire: ffffffff8e8112d8 (disc_data_lock){.+.+}-{2:2}, at: sp_get+0x18/0xf0 drivers/net/hamradio/6pack.c:376 and this task is already holding: ffffffff949172f8 (&port_lock_key){-.-.}-{2:2}, at: uart_port_lock_irqsave include/linux/serial_core.h:616 [inline] ffffffff949172f8 (&port_lock_key){-.-.}-{2:2}, at: uart_write+0x13a/0x5a0 drivers/tty/serial/serial_core.c:595 which would create a new lock dependency: (&port_lock_key){-.-.}-{2:2} -> (disc_data_lock){.+.+}-{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 kernel/locking/lockdep.c:5754 [inline] lock_acquire+0x1b1/0x540 kernel/locking/lockdep.c:5719 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162 uart_port_lock_irqsave include/linux/serial_core.h:616 [inline] serial8250_handle_irq+0x95/0x780 drivers/tty/serial/8250/8250_port.c:1913 serial8250_default_handle_irq+0x9a/0x210 drivers/tty/serial/8250/8250_port.c:1962 serial8250_interrupt+0x103/0x210 drivers/tty/serial/8250/8250_core.c:127 __handle_irq_event_percpu+0x229/0x750 kernel/irq/handle.c:158 handle_irq_event_percpu kernel/irq/handle.c:193 [inline] handle_irq_event+0xab/0x1e0 kernel/irq/handle.c:210 handle_edge_irq+0x263/0xd10 kernel/irq/chip.c:831 generic_handle_irq_desc include/linux/irqdesc.h:161 [inline] handle_irq arch/x86/kernel/irq.c:238 [inline] __common_interrupt+0xde/0x250 arch/x86/kernel/irq.c:257 common_interrupt+0xab/0xd0 arch/x86/kernel/irq.c:247 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline] _raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:194 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] uart_port_unlock_irqrestore include/linux/serial_core.h:667 [inline] serial_port_runtime_resume+0x2b7/0x340 drivers/tty/serial/serial_port.c:41 __rpm_callback+0xc5/0x4c0 drivers/base/power/runtime.c:394 rpm_callback+0x1da/0x220 drivers/base/power/runtime.c:448 rpm_resume+0xcf9/0x12f0 drivers/base/power/runtime.c:914 pm_runtime_work+0x10c/0x150 drivers/base/power/runtime.c:979 process_one_work+0x9a9/0x1a60 kernel/workqueue.c:3254 process_scheduled_works kernel/workqueue.c:3335 [inline] worker_thread+0x6c8/0xf70 kernel/workqueue.c:3416 kthread+0x2c1/0x3a0 kernel/kthread.c:388 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243 to a HARDIRQ-irq-unsafe lock: (disc_data_lock){.+.+}-{2:2} ... which became HARDIRQ-irq-unsafe at: ... lock_acquire kernel/locking/lockdep.c:5754 [inline] lock_acquire+0x1b1/0x540 kernel/locking/lockdep.c:5719 __raw_read_lock include/linux/rwlock_api_smp.h:150 [inline] _raw_read_lock+0x5f/0x70 kernel/locking/spinlock.c:228 sp_get+0x18/0xf0 drivers/net/hamradio/6pack.c:376 sixpack_receive_buf drivers/net/hamradio/6pack.c:439 [inline] sixpack_receive_buf+0x59/0x1c90 drivers/net/hamradio/6pack.c:430 tiocsti drivers/tty/tty_io.c:2299 [inline] tty_ioctl+0x581/0x1590 drivers/tty/tty_io.c:2717 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:904 [inline] __se_sys_ioctl fs/ioctl.c:890 [inline] __x64_sys_ioctl+0x193/0x220 fs/ioctl.c:890 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xd2/0x260 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x6d/0x75 other info that might help us debug this: Possible interrupt unsafe locking scenario: CPU0 CPU1 ---- ---- lock(disc_data_lock); local_irq_disable(); lock(&port_lock_key); lock(disc_data_lock); lock(&port_lock_key); *** DEADLOCK *** 6 locks held by kworker/u8:3/50: #0: ffff888015081148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x1296/0x1a60 kernel/workqueue.c:3229 #1: ffffc90000ba7d80 ((work_completion)(&buf->work)){+.+.}-{0:0}, at: process_one_work+0x906/0x1a60 kernel/workqueue.c:3230 #2: ffff88801f970ce8 (&buf->lock){+.+.}-{3:3}, at: flush_to_ldisc+0x31/0x780 drivers/tty/tty_buffer.c:466 #3: ffff8880614130a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref+0x1c/0x80 drivers/tty/tty_ldisc.c:263 #4: ffffffff949172f8 (&port_lock_key){-.-.}-{2:2}, at: uart_port_lock_irqsave include/linux/serial_core.h:616 [inline] #4: ffffffff949172f8 (&port_lock_key){-.-.}-{2:2}, at: uart_write+0x13a/0x5a0 drivers/tty/serial/serial_core.c:595 #5: ffff8880614130a0 (&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 kernel/locking/lockdep.c:5754 [inline] lock_acquire+0x1b1/0x540 kernel/locking/lockdep.c:5719 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162 uart_port_lock_irqsave include/linux/serial_core.h:616 [inline] serial8250_handle_irq+0x95/0x780 drivers/tty/serial/8250/8250_port.c:1913 serial8250_default_handle_irq+0x9a/0x210 drivers/tty/serial/8250/8250_port.c:1962 serial8250_interrupt+0x103/0x210 drivers/tty/serial/8250/8250_core.c:127 __handle_irq_event_percpu+0x229/0x750 kernel/irq/handle.c:158 handle_irq_event_percpu kernel/irq/handle.c:193 [inline] handle_irq_event+0xab/0x1e0 kernel/irq/handle.c:210 handle_edge_irq+0x263/0xd10 kernel/irq/chip.c:831 generic_handle_irq_desc include/linux/irqdesc.h:161 [inline] handle_irq arch/x86/kernel/irq.c:238 [inline] __common_interrupt+0xde/0x250 arch/x86/kernel/irq.c:257 common_interrupt+0xab/0xd0 arch/x86/kernel/irq.c:247 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline] _raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:194 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] uart_port_unlock_irqrestore include/linux/serial_core.h:667 [inline] serial_port_runtime_resume+0x2b7/0x340 drivers/tty/serial/serial_port.c:41 __rpm_callback+0xc5/0x4c0 drivers/base/power/runtime.c:394 rpm_callback+0x1da/0x220 drivers/base/power/runtime.c:448 rpm_resume+0xcf9/0x12f0 drivers/base/power/runtime.c:914 pm_runtime_work+0x10c/0x150 drivers/base/power/runtime.c:979 process_one_work+0x9a9/0x1a60 kernel/workqueue.c:3254 process_scheduled_works kernel/workqueue.c:3335 [inline] worker_thread+0x6c8/0xf70 kernel/workqueue.c:3416 kthread+0x2c1/0x3a0 kernel/kthread.c:388 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243 IN-SOFTIRQ-W at: lock_acquire kernel/locking/lockdep.c:5754 [inline] lock_acquire+0x1b1/0x540 kernel/locking/lockdep.c:5719 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162 uart_port_lock_irqsave include/linux/serial_core.h:616 [inline] serial8250_handle_irq+0x95/0x780 drivers/tty/serial/8250/8250_port.c:1913 serial8250_default_handle_irq+0x9a/0x210 drivers/tty/serial/8250/8250_port.c:1962 serial8250_interrupt+0x103/0x210 drivers/tty/serial/8250/8250_core.c:127 __handle_irq_event_percpu+0x229/0x750 kernel/irq/handle.c:158 handle_irq_event_percpu kernel/irq/handle.c:193 [inline] handle_irq_event+0xab/0x1e0 kernel/irq/handle.c:210 handle_edge_irq+0x263/0xd10 kernel/irq/chip.c:831 generic_handle_irq_desc include/linux/irqdesc.h:161 [inline] handle_irq arch/x86/kernel/irq.c:238 [inline] __common_interrupt+0xde/0x250 arch/x86/kernel/irq.c:257 common_interrupt+0x52/0xd0 arch/x86/kernel/irq.c:247 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693 check_kcov_mode kernel/kcov.c:173 [inline] __sanitizer_cov_trace_pc+0x18/0x60 kernel/kcov.c:207 orc_find arch/x86/kernel/unwind_orc.c:206 [inline] unwind_next_frame+0x1cf/0x23a0 arch/x86/kernel/unwind_orc.c:494 arch_stack_walk+0x100/0x170 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x95/0xd0 kernel/stacktrace.c:122 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:579 poison_slab_object mm/kasan/common.c:240 [inline] __kasan_slab_free+0x11d/0x1a0 mm/kasan/common.c:256 kasan_slab_free include/linux/kasan.h:184 [inline] slab_free_hook mm/slub.c:2106 [inline] slab_free mm/slub.c:4280 [inline] kmem_cache_free+0x12e/0x360 mm/slub.c:4344 rcu_do_batch kernel/rcu/tree.c:2196 [inline] rcu_core+0x828/0x16b0 kernel/rcu/tree.c:2471 __do_softirq+0x218/0x8de kernel/softirq.c:554 invoke_softirq kernel/softirq.c:428 [inline] __irq_exit_rcu kernel/softirq.c:633 [inline] irq_exit_rcu+0xb9/0x120 kernel/softirq.c:645 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline] sysvec_apic_timer_interrupt+0x95/0xb0 arch/x86/kernel/apic/apic.c:1043 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 seqcount_lockdep_reader_access include/linux/seqlock.h:74 [inline] read_seqbegin include/linux/seqlock.h:772 [inline] zone_span_seqbegin include/linux/memory_hotplug.h:134 [inline] page_outside_zone_boundaries mm/page_alloc.c:450 [inline] bad_range+0xcd/0x440 mm/page_alloc.c:469 rmqueue mm/page_alloc.c:2916 [inline] get_page_from_freelist+0xa08/0x3780 mm/page_alloc.c:3308 __alloc_pages+0x22b/0x2410 mm/page_alloc.c:4569 __alloc_pages_node include/linux/gfp.h:238 [inline] alloc_pages_node include/linux/gfp.h:261 [inline] alloc_slab_page mm/slub.c:2175 [inline] allocate_slab mm/slub.c:2338 [inline] new_slab+0xcc/0x3a0 mm/slub.c:2391 ___slab_alloc+0x66d/0x1790 mm/slub.c:3525 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3610 __slab_alloc_node mm/slub.c:3663 [inline] slab_alloc_node mm/slub.c:3835 [inline] kmem_cache_alloc_lru+0x379/0x6f0 mm/slub.c:3864 alloc_inode_sb include/linux/fs.h:3088 [inline] alloc_inode+0xba/0x230 fs/inode.c:263 iget_locked+0x1a1/0x6d0 fs/inode.c:1280 kernfs_get_inode+0x48/0x460 fs/kernfs/inode.c:251 kernfs_iop_lookup+0x1e9/0x330 fs/kernfs/dir.c:1205 __lookup_slow+0x24f/0x460 fs/namei.c:1692 lookup_slow fs/namei.c:1709 [inline] walk_component+0x350/0x5b0 fs/namei.c:2004 link_path_walk.part.0.constprop.0+0x77f/0xcd0 fs/namei.c:2331 link_path_walk fs/namei.c:2255 [inline] path_lookupat+0x93/0x770 fs/namei.c:2484 filename_lookup+0x1e5/0x5b0 fs/namei.c:2514 vfs_statx+0x13e/0x550 fs/stat.c:244 vfs_fstatat+0xb3/0x150 fs/stat.c:304 __do_sys_newfstatat+0x98/0x120 fs/stat.c:468 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xd2/0x260 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x6d/0x75 INITIAL USE at: lock_acquire kernel/locking/lockdep.c:5754 [inline] lock_acquire+0x1b1/0x540 kernel/locking/lockdep.c:5719 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162 uart_port_lock_irqsave include/linux/serial_core.h:616 [inline] serial8250_do_set_termios+0x334/0x1270 drivers/tty/serial/8250/8250_port.c:2793 serial8250_set_termios+0x6e/0x80 drivers/tty/serial/8250/8250_port.c:2912 uart_set_options+0x31b/0x5f0 drivers/tty/serial/serial_core.c:2320 serial8250_console_setup+0x18a/0x460 drivers/tty/serial/8250/8250_port.c:3507 univ8250_console_setup+0x16c/0x210 drivers/tty/serial/8250/8250_core.c:632 try_enable_preferred_console+0x253/0x480 kernel/printk/printk.c:3308 register_console+0x30e/0x1060 kernel/printk/printk.c:3485 univ8250_console_init+0x35/0x50 drivers/tty/serial/8250/8250_core.c:717 console_init+0xcc/0x5e0 kernel/printk/printk.c:3694 start_kernel+0x259/0x490 init/main.c:1012 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:509 x86_64_start_kernel+0xb2/0xc0 arch/x86/kernel/head64.c:490 common_startup_64+0x13e/0x148 } ... key at: [] port_lock_key+0x0/0x40 the dependencies between the lock to be acquired and HARDIRQ-irq-unsafe lock: -> (disc_data_lock){.+.+}-{2:2} { HARDIRQ-ON-R at: lock_acquire kernel/locking/lockdep.c:5754 [inline] lock_acquire+0x1b1/0x540 kernel/locking/lockdep.c:5719 __raw_read_lock include/linux/rwlock_api_smp.h:150 [inline] _raw_read_lock+0x5f/0x70 kernel/locking/spinlock.c:228 sp_get+0x18/0xf0 drivers/net/hamradio/6pack.c:376 sixpack_receive_buf drivers/net/hamradio/6pack.c:439 [inline] sixpack_receive_buf+0x59/0x1c90 drivers/net/hamradio/6pack.c:430 tiocsti drivers/tty/tty_io.c:2299 [inline] tty_ioctl+0x581/0x1590 drivers/tty/tty_io.c:2717 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:904 [inline] __se_sys_ioctl fs/ioctl.c:890 [inline] __x64_sys_ioctl+0x193/0x220 fs/ioctl.c:890 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xd2/0x260 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x6d/0x75 SOFTIRQ-ON-R at: lock_acquire kernel/locking/lockdep.c:5754 [inline] lock_acquire+0x1b1/0x540 kernel/locking/lockdep.c:5719 __raw_read_lock include/linux/rwlock_api_smp.h:150 [inline] _raw_read_lock+0x5f/0x70 kernel/locking/spinlock.c:228 sp_get+0x18/0xf0 drivers/net/hamradio/6pack.c:376 sixpack_receive_buf drivers/net/hamradio/6pack.c:439 [inline] sixpack_receive_buf+0x59/0x1c90 drivers/net/hamradio/6pack.c:430 tiocsti drivers/tty/tty_io.c:2299 [inline] tty_ioctl+0x581/0x1590 drivers/tty/tty_io.c:2717 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:904 [inline] __se_sys_ioctl fs/ioctl.c:890 [inline] __x64_sys_ioctl+0x193/0x220 fs/ioctl.c:890 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xd2/0x260 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x6d/0x75 INITIAL USE at: lock_acquire kernel/locking/lockdep.c:5754 [inline] lock_acquire+0x1b1/0x540 kernel/locking/lockdep.c:5719 __raw_write_lock_irq include/linux/rwlock_api_smp.h:195 [inline] _raw_write_lock_irq+0x36/0x50 kernel/locking/spinlock.c:326 sixpack_close+0x1e/0x2d0 drivers/net/hamradio/6pack.c:653 tty_ldisc_close+0x111/0x1a0 drivers/tty/tty_ldisc.c:455 tty_ldisc_kill+0x8e/0x150 drivers/tty/tty_ldisc.c:607 tty_ldisc_release+0x17b/0x2a0 drivers/tty/tty_ldisc.c:775 tty_release_struct+0x23/0xe0 drivers/tty/tty_io.c:1696 tty_release+0xe33/0x1420 drivers/tty/tty_io.c:1867 __fput+0x270/0xb80 fs/file_table.c:422 __fput_sync+0x47/0x50 fs/file_table.c:507 __do_sys_close fs/open.c:1556 [inline] __se_sys_close fs/open.c:1541 [inline] __x64_sys_close+0x86/0x100 fs/open.c:1541 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xd2/0x260 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x6d/0x75 INITIAL READ USE at: lock_acquire kernel/locking/lockdep.c:5754 [inline] lock_acquire+0x1b1/0x540 kernel/locking/lockdep.c:5719 __raw_read_lock include/linux/rwlock_api_smp.h:150 [inline] _raw_read_lock+0x5f/0x70 kernel/locking/spinlock.c:228 sp_get+0x18/0xf0 drivers/net/hamradio/6pack.c:376 sixpack_receive_buf drivers/net/hamradio/6pack.c:439 [inline] sixpack_receive_buf+0x59/0x1c90 drivers/net/hamradio/6pack.c:430 tiocsti drivers/tty/tty_io.c:2299 [inline] tty_ioctl+0x581/0x1590 drivers/tty/tty_io.c:2717 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:904 [inline] __se_sys_ioctl fs/ioctl.c:890 [inline] __x64_sys_ioctl+0x193/0x220 fs/ioctl.c:890 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xd2/0x260 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x6d/0x75 } ... key at: [] disc_data_lock+0x18/0xf20 ... acquired at: lock_acquire kernel/locking/lockdep.c:5754 [inline] lock_acquire+0x1b1/0x540 kernel/locking/lockdep.c:5719 __raw_read_lock include/linux/rwlock_api_smp.h:150 [inline] _raw_read_lock+0x5f/0x70 kernel/locking/spinlock.c:228 sp_get+0x18/0xf0 drivers/net/hamradio/6pack.c:376 sixpack_write_wakeup+0x20/0x390 drivers/net/hamradio/6pack.c:397 tty_wakeup+0xe5/0x120 drivers/tty/tty_io.c:523 tty_port_default_wakeup+0x2a/0x40 drivers/tty/tty_port.c:69 serial8250_tx_chars+0x55a/0x8b0 drivers/tty/serial/8250/8250_port.c:1835 __start_tx+0x3e9/0x4a0 drivers/tty/serial/8250/8250_port.c:1544 serial8250_start_tx+0x363/0x530 drivers/tty/serial/8250/8250_port.c:1653 __uart_start+0x26d/0x440 drivers/tty/serial/serial_core.c:160 uart_write+0x301/0x5a0 drivers/tty/serial/serial_core.c:615 decode_prio_command drivers/net/hamradio/6pack.c:888 [inline] sixpack_decode drivers/net/hamradio/6pack.c:963 [inline] sixpack_receive_buf drivers/net/hamradio/6pack.c:453 [inline] sixpack_receive_buf+0x3fd/0x1c90 drivers/net/hamradio/6pack.c:430 tty_ldisc_receive_buf+0x153/0x190 drivers/tty/tty_buffer.c:390 tty_port_default_receive_buf+0x70/0xb0 drivers/tty/tty_port.c:37 receive_buf drivers/tty/tty_buffer.c:444 [inline] flush_to_ldisc+0x264/0x780 drivers/tty/tty_buffer.c:494 process_one_work+0x9a9/0x1a60 kernel/workqueue.c:3254 process_scheduled_works kernel/workqueue.c:3335 [inline] worker_thread+0x6c8/0xf70 kernel/workqueue.c:3416 kthread+0x2c1/0x3a0 kernel/kthread.c:388 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243 stack backtrace: CPU: 1 PID: 50 Comm: kworker/u8:3 Not tainted 6.8.0-syzkaller-08951-gfe46a7dd189e #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024 Workqueue: events_unbound flush_to_ldisc Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114 print_bad_irq_dependency kernel/locking/lockdep.c:2626 [inline] check_irq_usage+0xe3c/0x1490 kernel/locking/lockdep.c:2865 check_prev_add kernel/locking/lockdep.c:3138 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3869 [inline] __lock_acquire+0x248e/0x3b30 kernel/locking/lockdep.c:5137 lock_acquire kernel/locking/lockdep.c:5754 [inline] lock_acquire+0x1b1/0x540 kernel/locking/lockdep.c:5719 __raw_read_lock include/linux/rwlock_api_smp.h:150 [inline] _raw_read_lock+0x5f/0x70 kernel/locking/spinlock.c:228 sp_get+0x18/0xf0 drivers/net/hamradio/6pack.c:376 sixpack_write_wakeup+0x20/0x390 drivers/net/hamradio/6pack.c:397 tty_wakeup+0xe5/0x120 drivers/tty/tty_io.c:523 tty_port_default_wakeup+0x2a/0x40 drivers/tty/tty_port.c:69 serial8250_tx_chars+0x55a/0x8b0 drivers/tty/serial/8250/8250_port.c:1835 __start_tx+0x3e9/0x4a0 drivers/tty/serial/8250/8250_port.c:1544 serial8250_start_tx+0x363/0x530 drivers/tty/serial/8250/8250_port.c:1653 __uart_start+0x26d/0x440 drivers/tty/serial/serial_core.c:160 uart_write+0x301/0x5a0 drivers/tty/serial/serial_core.c:615 decode_prio_command drivers/net/hamradio/6pack.c:888 [inline] sixpack_decode drivers/net/hamradio/6pack.c:963 [inline] sixpack_receive_buf drivers/net/hamradio/6pack.c:453 [inline] sixpack_receive_buf+0x3fd/0x1c90 drivers/net/hamradio/6pack.c:430 tty_ldisc_receive_buf+0x153/0x190 drivers/tty/tty_buffer.c:390 tty_port_default_receive_buf+0x70/0xb0 drivers/tty/tty_port.c:37 receive_buf drivers/tty/tty_buffer.c:444 [inline] flush_to_ldisc+0x264/0x780 drivers/tty/tty_buffer.c:494 process_one_work+0x9a9/0x1 kernel/workqueue.c:3254