ci starts bisection 2023-06-07 02:53:57.834930801 +0000 UTC m=+478391.332885334 bisecting fixing commit since 1a61b828566fba088d3baa0dc3e440b51fdf9ce2 building syzkaller on 0042f2b4c00ce1ceeaa44a0147909fe3a6f86c5c ensuring issue is reproducible on original commit 1a61b828566fba088d3baa0dc3e440b51fdf9ce2 testing commit 1a61b828566fba088d3baa0dc3e440b51fdf9ce2 gcc compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: 6e4fd8ce7d69489839154beb60b7ade23ee60a961175dd0498bbdfa7b0ea96dd all runs: crashed: BUG: sleeping function called from invalid context in gsm_send testing current HEAD a4d7d701121981e3c3fe69ade376fe9f26324161 testing commit a4d7d701121981e3c3fe69ade376fe9f26324161 gcc compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: 7c4faf2515567b9cc5aa0b7d81abe8a894634ffdfc1d899cd1d273693668660d all runs: crashed: BUG: sleeping function called from invalid context in console_lock crash still not fixed/happens on the oldest tested release revisions tested: 2, total time: 31m17.926027394s (build: 23m12.681037099s, test: 6m13.871720482s) crash still not fixed on HEAD or HEAD had kernel test errors commit msg: Merge tag 'spi-fix-v6.4-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi crash: BUG: sleeping function called from invalid context in console_lock BUG: sleeping function called from invalid context at kernel/printk/printk.c:2598 in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 22, name: kworker/1:0 preempt_count: 1, expected: 0 RCU nest depth: 0, expected: 0 3 locks held by kworker/1:0/22: #0: ffff888010c70d38 ((wq_completion)events){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff888010c70d38 ((wq_completion)events){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline] #0: ffff888010c70d38 ((wq_completion)events){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1324 [inline] #0: ffff888010c70d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:643 [inline] #0: ffff888010c70d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:670 [inline] #0: ffff888010c70d38 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x793/0x1410 kernel/workqueue.c:2376 #1: ffffc900001c7dc0 ((work_completion)(&gsm->tx_work)){+.+.}-{0:0}, at: process_one_work+0x7c0/0x1410 kernel/workqueue.c:2380 #2: ffff88801bf553e0 (&gsm->tx_lock){....}-{2:2}, at: gsmld_write_task+0x2c/0xd60 drivers/tty/n_gsm.c:3444 irq event stamp: 259516 hardirqs last enabled at (259515): [] __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:159 [inline] hardirqs last enabled at (259515): [] _raw_spin_unlock_irq+0x1f/0x40 kernel/locking/spinlock.c:202 hardirqs last disabled at (259516): [] __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:108 [inline] hardirqs last disabled at (259516): [] _raw_spin_lock_irqsave+0x4e/0x50 kernel/locking/spinlock.c:162 softirqs last enabled at (259494): [] do_softirq.part.0+0xde/0x130 kernel/softirq.c:472 softirqs last disabled at (259459): [] do_softirq.part.0+0xde/0x130 kernel/softirq.c:472 Preemption disabled at: [<0000000000000000>] 0x0 CPU: 1 PID: 22 Comm: kworker/1:0 Not tainted 6.4.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023 Workqueue: events gsmld_write_task Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x60/0xa0 lib/dump_stack.c:106 __might_resched+0x354/0x580 kernel/sched/core.c:10153 console_lock+0x11/0x60 kernel/printk/printk.c:2598 do_con_write+0xf2/0x19c0 drivers/tty/vt/vt.c:2863 con_write+0xb/0x20 drivers/tty/vt/vt.c:3246 gsmld_output drivers/tty/n_gsm.c:3411 [inline] gsm_send_packet+0x35d/0x940 drivers/tty/n_gsm.c:962 gsm_data_kick drivers/tty/n_gsm.c:1024 [inline] gsmld_write_task+0x1d6/0xd60 drivers/tty/n_gsm.c:3446 process_one_work+0x86e/0x1410 kernel/workqueue.c:2405 worker_thread+0x5ab/0xef0 kernel/workqueue.c:2552 kthread+0x2e6/0x3c0 kernel/kthread.c:379 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 ===================================================== WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected 6.4.0-rc5-syzkaller #0 Tainted: G W ----------------------------------------------------- kworker/1:0/22 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire: ffffffff8b175ba0 (console_lock){+.+.}-{0:0}, at: do_con_write+0xf2/0x19c0 drivers/tty/vt/vt.c:2863 and this task is already holding: ffff88801bf553e0 (&gsm->tx_lock){..-.}-{2:2}, at: gsmld_write_task+0x2c/0xd60 drivers/tty/n_gsm.c:3444 which would create a new lock dependency: (&gsm->tx_lock){..-.}-{2:2} -> (console_lock){+.+.}-{0:0} but this new dependency connects a SOFTIRQ-irq-safe lock: (&gsm->tx_lock){..-.}-{2:2} ... which became SOFTIRQ-irq-safe at: lock_acquire kernel/locking/lockdep.c:5705 [inline] lock_acquire+0x1ad/0x520 kernel/locking/lockdep.c:5670 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x39/0x50 kernel/locking/spinlock.c:162 gsm_send.isra.0+0x32d/0x840 drivers/tty/n_gsm.c:834 gsm_command drivers/tty/n_gsm.c:898 [inline] gsm_dlci_begin_close+0x113/0x210 drivers/tty/n_gsm.c:2364 gsm_dlci_t1+0x1a4/0x540 drivers/tty/n_gsm.c:2239 call_timer_fn+0x163/0x400 kernel/time/timer.c:1700 expire_timers+0x224/0x400 kernel/time/timer.c:1751 __run_timers kernel/time/timer.c:2022 [inline] __run_timers kernel/time/timer.c:1995 [inline] run_timer_softirq+0x292/0x790 kernel/time/timer.c:2035 __do_softirq+0x1d0/0x901 kernel/softirq.c:571 invoke_softirq kernel/softirq.c:445 [inline] __irq_exit_rcu+0x114/0x190 kernel/softirq.c:650 irq_exit_rcu+0x5/0x20 kernel/softirq.c:662 sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1106 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:645 percpu_counter_add_batch+0xff/0x160 lib/percpu_counter.c:103 percpu_counter_add include/linux/percpu_counter.h:58 [inline] add_mm_counter include/linux/mm.h:2471 [inline] add_mm_rss_vec mm/memory.c:480 [inline] zap_pte_range mm/memory.c:1496 [inline] zap_pmd_range mm/memory.c:1563 [inline] zap_pud_range mm/memory.c:1592 [inline] zap_p4d_range mm/memory.c:1613 [inline] unmap_page_range+0x100b/0x2d90 mm/memory.c:1634 unmap_vmas+0x222/0x360 mm/memory.c:1719 exit_mmap+0x168/0x750 mm/mmap.c:3111 __mmput+0xf3/0x440 kernel/fork.c:1351 exit_mm kernel/exit.c:567 [inline] do_exit+0x855/0x24c0 kernel/exit.c:861 do_group_exit+0xb0/0x250 kernel/exit.c:1024 __do_sys_exit_group kernel/exit.c:1035 [inline] __se_sys_exit_group kernel/exit.c:1033 [inline] __x64_sys_exit_group+0x35/0x40 kernel/exit.c:1033 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd to a SOFTIRQ-irq-unsafe lock: (console_lock){+.+.}-{0:0} ... which became SOFTIRQ-irq-unsafe at: ... lock_acquire kernel/locking/lockdep.c:5705 [inline] lock_acquire+0x1ad/0x520 kernel/locking/lockdep.c:5670 console_lock+0x40/0x60 kernel/printk/printk.c:2600 con_init+0x11/0x710 drivers/tty/vt/vt.c:3439 console_init+0x80/0x3f0 kernel/printk/printk.c:3601 start_kernel+0x1fc/0x340 init/main.c:1014 x86_64_start_reservations+0x14/0x30 arch/x86/kernel/head64.c:556 x86_64_start_kernel+0xaf/0xc0 arch/x86/kernel/head64.c:537 secondary_startup_64_no_verify+0xf4/0xfb other info that might help us debug this: Possible interrupt unsafe locking scenario: CPU0 CPU1 ---- ---- lock(console_lock); local_irq_disable(); lock(&gsm->tx_lock); lock(console_lock); lock(&gsm->tx_lock); *** DEADLOCK *** 3 locks held by kworker/1:0/22: #0: ffff888010c70d38 ((wq_completion)events){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff888010c70d38 ((wq_completion)events){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline] #0: ffff888010c70d38 ((wq_completion)events){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1324 [inline] #0: ffff888010c70d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:643 [inline] #0: ffff888010c70d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:670 [inline] #0: ffff888010c70d38 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x793/0x1410 kernel/workqueue.c:2376 #1: ffffc900001c7dc0 ((work_completion)(&gsm->tx_work)){+.+.}-{0:0}, at: process_one_work+0x7c0/0x1410 kernel/workqueue.c:2380 #2: ffff88801bf553e0 (&gsm->tx_lock){..-.}-{2:2}, at: gsmld_write_task+0x2c/0xd60 drivers/tty/n_gsm.c:3444 the dependencies between SOFTIRQ-irq-safe lock and the holding lock: -> (&gsm->tx_lock){..-.}-{2:2} { IN-SOFTIRQ-W at: lock_acquire kernel/locking/lockdep.c:5705 [inline] lock_acquire+0x1ad/0x520 kernel/locking/lockdep.c:5670 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x39/0x50 kernel/locking/spinlock.c:162 gsm_send.isra.0+0x32d/0x840 drivers/tty/n_gsm.c:834 gsm_command drivers/tty/n_gsm.c:898 [inline] gsm_dlci_begin_close+0x113/0x210 drivers/tty/n_gsm.c:2364 gsm_dlci_t1+0x1a4/0x540 drivers/tty/n_gsm.c:2239 call_timer_fn+0x163/0x400 kernel/time/timer.c:1700 expire_timers+0x224/0x400 kernel/time/timer.c:1751 __run_timers kernel/time/timer.c:2022 [inline] __run_timers kernel/time/timer.c:1995 [inline] run_timer_softirq+0x292/0x790 kernel/time/timer.c:2035 __do_softirq+0x1d0/0x901 kernel/softirq.c:571 invoke_softirq kernel/softirq.c:445 [inline] __irq_exit_rcu+0x114/0x190 kernel/softirq.c:650 irq_exit_rcu+0x5/0x20 kernel/softirq.c:662 sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1106 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:645 percpu_counter_add_batch+0xff/0x160 lib/percpu_counter.c:103 percpu_counter_add include/linux/percpu_counter.h:58 [inline] add_mm_counter include/linux/mm.h:2471 [inline] add_mm_rss_vec mm/memory.c:480 [inline] zap_pte_range mm/memory.c:1496 [inline] zap_pmd_range mm/memory.c:1563 [inline] zap_pud_range mm/memory.c:1592 [inline] zap_p4d_range mm/memory.c:1613 [inline] unmap_page_range+0x100b/0x2d90 mm/memory.c:1634 unmap_vmas+0x222/0x360 mm/memory.c:1719 exit_mmap+0x168/0x750 mm/mmap.c:3111 __mmput+0xf3/0x440 kernel/fork.c:1351 exit_mm kernel/exit.c:567 [inline] do_exit+0x855/0x24c0 kernel/exit.c:861 do_group_exit+0xb0/0x250 kernel/exit.c:1024 __do_sys_exit_group kernel/exit.c:1035 [inline] __se_sys_exit_group kernel/exit.c:1033 [inline] __x64_sys_exit_group+0x35/0x40 kernel/exit.c:1033 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd INITIAL USE at: lock_acquire kernel/locking/lockdep.c:5705 [inline] lock_acquire+0x1ad/0x520 kernel/locking/lockdep.c:5670 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x39/0x50 kernel/locking/spinlock.c:162 gsm_send.isra.0+0x32d/0x840 drivers/tty/n_gsm.c:834 gsm_command drivers/tty/n_gsm.c:898 [inline] gsm_dlci_begin_open+0x346/0x5c0 drivers/tty/n_gsm.c:2292 gsm_config drivers/tty/n_gsm.c:3359 [inline] gsmld_ioctl+0x10e0/0x16a0 drivers/tty/n_gsm.c:3733 tty_ioctl+0x548/0x1280 drivers/tty/tty_io.c:2786 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl fs/ioctl.c:856 [inline] __x64_sys_ioctl+0x11f/0x190 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd } ... key at: [] __key.10+0x0/0x40 the dependencies between the lock to be acquired and SOFTIRQ-irq-unsafe lock: -> (console_lock){+.+.}-{0:0} { HARDIRQ-ON-W at: lock_acquire kernel/locking/lockdep.c:5705 [inline] lock_acquire+0x1ad/0x520 kernel/locking/lockdep.c:5670 console_lock+0x40/0x60 kernel/printk/printk.c:2600 con_init+0x11/0x710 drivers/tty/vt/vt.c:3439 console_init+0x80/0x3f0 kernel/printk/printk.c:3601 start_kernel+0x1fc/0x340 init/main.c:1014 x86_64_start_reservations+0x14/0x30 arch/x86/kernel/head64.c:556 x86_64_start_kernel+0xaf/0xc0 arch/x86/kernel/head64.c:537 secondary_startup_64_no_verify+0xf4/0xfb SOFTIRQ-ON-W at: lock_acquire kernel/locking/lockdep.c:5705 [inline] lock_acquire+0x1ad/0x520 kernel/locking/lockdep.c:5670 console_lock+0x40/0x60 kernel/printk/printk.c:2600 con_init+0x11/0x710 drivers/tty/vt/vt.c:3439 console_init+0x80/0x3f0 kernel/printk/printk.c:3601 start_kernel+0x1fc/0x340 init/main.c:1014 x86_64_start_reservations+0x14/0x30 arch/x86/kernel/head64.c:556 x86_64_start_kernel+0xaf/0xc0 arch/x86/kernel/head64.c:537 secondary_startup_64_no_verify+0xf4/0xfb INITIAL USE at: } ... key at: [] console_lock_dep_map+0x0/0x60 ... acquired at: lock_acquire kernel/locking/lockdep.c:5705 [inline] lock_acquire+0x1ad/0x520 kernel/locking/lockdep.c:5670 console_lock+0x40/0x60 kernel/printk/printk.c:2600 do_con_write+0xf2/0x19c0 drivers/tty/vt/vt.c:2863 con_write+0xb/0x20 drivers/tty/vt/vt.c:3246 gsmld_output drivers/tty/n_gsm.c:3411 [inline] gsm_send_packet+0x35d/0x940 drivers/tty/n_gsm.c:962 gsm_data_kick drivers/tty/n_gsm.c:1024 [inline] gsmld_write_task+0x1d6/0xd60 drivers/tty/n_gsm.c:3446 process_one_work+0x86e/0x1410 kernel/workqueue.c:2405 worker_thread+0x5ab/0xef0 kernel/workqueue.c:2552 kthread+0x2e6/0x3c0 kernel/kthread.c:379 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 stack backtrace: CPU: 1 PID: 22 Comm: kworker/1:0 Tainted: G W 6.4.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023 Workqueue: events gsmld_write_task Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x60/0xa0 lib/dump_stack.c:106 print_bad_irq_dependency kernel/locking/lockdep.c:2627 [inline] check_irq_usage+0x114e/0x1a40 kernel/locking/lockdep.c:2866 check_prev_add kernel/locking/lockdep.c:3117 [inline] check_prevs_add kernel/locking/lockdep.c:3232 [inline] validate_chain kernel/locking/lockdep.c:3847 [inline] __lock_acquire+0x2fe5/0x5f30 kernel/locking/lockdep.c:5088 lock_acquire kernel/locking/lockdep.c:5705 [inline] lock_acquire+0x1ad/0x520 kernel/locking/lockdep.c:5670 console_lock+0x40/0x60 kernel/printk/printk.c:2600 do_con_write+0xf2/0x19c0 drivers/tty/vt/vt.c:2863 con_write+0xb/0x20 drivers/tty/vt/vt.c:3246 gsmld_output drivers/tty/n_gsm.c:3411 [inline] gsm_send_packet+0x35d/0x940 drivers/tty/n_gsm.c:962 gsm_data_kick drivers/tty/n_gsm.c:1024 [inline] gsmld_write_task+0x1d6/0xd60 drivers/tty/n_gsm.c:3446 process_one_work+0x86e/0x1410 kernel/workqueue.c:2405 worker_thread+0x5ab/0xef0 kernel/workqueue.c:2552 kthread+0x2e6/0x3c0 kernel/kthread.c:379 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 BUG: sleeping function called from invalid context at kernel/printk/printk.c:2598 in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 22, name: kworker/1:0 preempt_count: 1, expected: 0 RCU nest depth: 0, expected: 0 INFO: lockdep is turned off. irq event stamp: 259516 hardirqs last enabled at (259515): [] __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:159 [inline] hardirqs last enabled at (259515): [] _raw_spin_unlock_irq+0x1f/0x40 kernel/locking/spinlock.c:202 hardirqs last disabled at (259516): [] __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:108 [inline] hardirqs last disabled at (259516): [] _raw_spin_lock_irqsave+0x4e/0x50 kernel/locking/spinlock.c:162 softirqs last enabled at (259494): [] do_softirq.part.0+0xde/0x130 kernel/softirq.c:472 softirqs last disabled at (259459): [] do_softirq.part.0+0xde/0x130 kernel/softirq.c:472 Preemption disabled at: [<0000000000000000>] 0x0 CPU: 1 PID: 22 Comm: kworker/1:0 Tainted: G W 6.4.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023 Workqueue: events gsmld_write_task Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x60/0xa0 lib/dump_stack.c:106 __might_resched+0x354/0x580 kernel/sched/core.c:10153 console_lock+0x11/0x60 kernel/printk/printk.c:2598 do_con_write+0xf2/0x19c0 drivers/tty/vt/vt.c:2863 con_write+0xb/0x20 drivers/tty/vt/vt.c:3246 gsmld_output drivers/tty/n_gsm.c:3411 [inline] gsm_send_packet+0x35d/0x940 drivers/tty/n_gsm.c:962 gsm_data_kick drivers/tty/n_gsm.c:1024 [inline] gsmld_write_task+0x1d6/0xd60 drivers/tty/n_gsm.c:3446 process_one_work+0x86e/0x1410 kernel/workqueue.c:2405 process_scheduled_works kernel/workqueue.c:2468 [inline] worker_thread+0x71b/0xef0 kernel/workqueue.c:2557 kthread+0x2e6/0x3c0 kernel/kthread.c:379 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 BUG: sleeping function called from invalid context at kernel/printk/printk.c:2598 in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 22, name: kworker/1:0 preempt_count: 1, expected: 0 RCU nest depth: 0, expected: 0 INFO: lockdep is turned off. irq event stamp: 259516 hardirqs last enabled at (259515): [] __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:159 [inline] hardirqs last enabled at (259515): [] _raw_spin_unlock_irq+0x1f/0x40 kernel/locking/spinlock.c:202 hardirqs last disabled at (259516): [] __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:108 [inline] hardirqs last disabled at (259516): [] _raw_spin_lock_irqsave+0x4e/0x50 kernel/locking/spinlock.c:162 softirqs last enabled at (259494): [] do_softirq.part.0+0xde/0x130 kernel/softirq.c:472 softirqs last disabled at (259459): [] do_softirq.part.0+0xde/0x130 kernel/softirq.c:472 Preemption disabled at: [<0000000000000000>] 0x0 CPU: 1 PID: 22 Comm: kworker/1:0 Tainted: G W 6.4.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023 Workqueue: events gsmld_write_task Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x60/0xa0 lib/dump_stack.c:106 __might_resched+0x354/0x580 kernel/sched/core.c:10153 console_lock+0x11/0x60 kernel/printk/printk.c:2598 do_con_write+0xf2/0x19c0 drivers/tty/vt/vt.c:2863 con_write+0xb/0x20 drivers/tty/vt/vt.c:3246 gsmld_output drivers/tty/n_gsm.c:3411 [inline] gsm_send_packet+0x35d/0x940 drivers/tty/n_gsm.c:962 gsm_data_kick drivers/tty/n_gsm.c:1024 [inline] gsmld_write_task+0x1d6/0xd60 drivers/tty/n_gsm.c:3446 process_one_work+0x86e/0x1410 kernel/workqueue.c:2405 worker_thread+0x5ab/0xef0 kernel/workqueue.c:2552 kthread+0x2e6/0x3c0 kernel/kthread.c:379 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308