BUG: sleeping function called from invalid context at kernel/locking/mutex.c:938 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 0, name: swapper/0 1 lock held by swapper/0/0: #0: ffffc90000007d50 ((&sp->resync_t)){+.-.}, at: lockdep_copy_map include/linux/lockdep.h:172 [inline] #0: ffffc90000007d50 ((&sp->resync_t)){+.-.}, at: call_timer_fn+0xe0/0x780 kernel/time/timer.c:1394 Preemption disabled at: [] schedule_preempt_disabled+0x1d/0x20 kernel/sched/core.c:4215 CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.4.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x197/0x210 lib/dump_stack.c:118 ___might_sleep.cold+0x1fb/0x23e kernel/sched/core.c:6800 __might_sleep+0x95/0x190 kernel/sched/core.c:6753 __mutex_lock_common kernel/locking/mutex.c:938 [inline] __mutex_lock+0xc5/0x13c0 kernel/locking/mutex.c:1106 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1121 tpk_write+0x5d/0x340 drivers/char/ttyprintk.c:122 resync_tnc+0x1b6/0x320 drivers/net/hamradio/6pack.c:522 call_timer_fn+0x1ac/0x780 kernel/time/timer.c:1404 expire_timers kernel/time/timer.c:1449 [inline] __run_timers kernel/time/timer.c:1773 [inline] __run_timers kernel/time/timer.c:1740 [inline] run_timer_softirq+0x6c3/0x1790 kernel/time/timer.c:1786 __do_softirq+0x262/0x98c kernel/softirq.c:292 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0x19b/0x1e0 kernel/softirq.c:413 exiting_irq arch/x86/include/asm/apic.h:536 [inline] smp_apic_timer_interrupt+0x1a3/0x610 arch/x86/kernel/apic/apic.c:1137 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829 RIP: 0010:native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:61 Code: 98 81 eb f9 eb 8a cc cc cc cc cc cc e9 07 00 00 00 0f 00 2d 04 83 61 00 f4 c3 66 90 e9 07 00 00 00 0f 00 2d f4 82 61 00 fb f4 cc 55 48 89 e5 41 57 41 56 41 55 41 54 53 e8 ce 93 9b f9 e8 79 RSP: 0018:ffffffff89807ce8 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 RAX: 1ffffffff13266ae RBX: ffffffff8987a1c0 RCX: 0000000000000000 RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffffffff8987aa54 RBP: ffffffff89807d18 R08: ffffffff8987a1c0 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: dffffc0000000000 R13: ffffffff8a790e80 R14: 0000000000000000 R15: 0000000000000000 arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:690 default_idle_call+0x84/0xb0 kernel/sched/idle.c:94 cpuidle_idle_call kernel/sched/idle.c:154 [inline] do_idle+0x3c8/0x6e0 kernel/sched/idle.c:269 cpu_startup_entry+0x1b/0x20 kernel/sched/idle.c:361 rest_init+0x23b/0x371 init/main.c:451 arch_call_rest_init+0xe/0x1b start_kernel+0x904/0x943 init/main.c:784 x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:490 x86_64_start_kernel+0x77/0x7b arch/x86/kernel/head64.c:471 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:242 ================================ WARNING: inconsistent lock state 5.4.0-syzkaller #0 Tainted: G W -------------------------------- inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage. swapper/0/0 [HC0[0]:SC1[1]:HE1:SE0] takes: ffffffff8c110ab0 (&tpk_port.port_write_mutex){+.?.}, at: tpk_write+0x5d/0x340 drivers/char/ttyprintk.c:122 {SOFTIRQ-ON-W} state was registered at: lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4485 __mutex_lock_common kernel/locking/mutex.c:959 [inline] __mutex_lock+0x156/0x13c0 kernel/locking/mutex.c:1106 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1121 tpk_write+0x5d/0x340 drivers/char/ttyprintk.c:122 tnc_init drivers/net/hamradio/6pack.c:536 [inline] sixpack_open+0x8d6/0xaaf drivers/net/hamradio/6pack.c:632 tty_ldisc_open.isra.0+0xa3/0x110 drivers/tty/tty_ldisc.c:464 tty_set_ldisc+0x30e/0x6b0 drivers/tty/tty_ldisc.c:591 tiocsetd drivers/tty/tty_io.c:2337 [inline] tty_ioctl+0xe8d/0x14f0 drivers/tty/tty_io.c:2597 vfs_ioctl fs/ioctl.c:47 [inline] file_ioctl fs/ioctl.c:545 [inline] do_vfs_ioctl+0x977/0x14e0 fs/ioctl.c:732 ksys_ioctl+0xab/0xd0 fs/ioctl.c:749 __do_sys_ioctl fs/ioctl.c:756 [inline] __se_sys_ioctl fs/ioctl.c:754 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:754 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe irq event stamp: 224496 hardirqs last enabled at (224496): [] trace_hardirqs_on_thunk+0x1a/0x1c arch/x86/entry/thunk_64.S:41 hardirqs last disabled at (224495): [] trace_hardirqs_off_thunk+0x1a/0x1c arch/x86/entry/thunk_64.S:42 softirqs last enabled at (224420): [] _local_bh_enable+0x1c/0x30 kernel/softirq.c:162 softirqs last disabled at (224421): [] invoke_softirq kernel/softirq.c:373 [inline] softirqs last disabled at (224421): [] irq_exit+0x19b/0x1e0 kernel/softirq.c:413 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&tpk_port.port_write_mutex); lock(&tpk_port.port_write_mutex); *** DEADLOCK *** 1 lock held by swapper/0/0: #0: ffffc90000007d50 ((&sp->resync_t)){+.-.}, at: lockdep_copy_map include/linux/lockdep.h:172 [inline] #0: ffffc90000007d50 ((&sp->resync_t)){+.-.}, at: call_timer_fn+0xe0/0x780 kernel/time/timer.c:1394 stack backtrace: CPU: 0 PID: 0 Comm: swapper/0 Tainted: G W 5.4.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x197/0x210 lib/dump_stack.c:118 print_usage_bug.cold+0x327/0x378 kernel/locking/lockdep.c:3101 valid_state kernel/locking/lockdep.c:3112 [inline] mark_lock_irq kernel/locking/lockdep.c:3309 [inline] mark_lock+0xbb4/0x1220 kernel/locking/lockdep.c:3666 mark_usage kernel/locking/lockdep.c:3566 [inline] __lock_acquire+0x1e8e/0x4a00 kernel/locking/lockdep.c:3909 lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4485 __mutex_lock_common kernel/locking/mutex.c:959 [inline] __mutex_lock+0x156/0x13c0 kernel/locking/mutex.c:1106 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1121 tpk_write+0x5d/0x340 drivers/char/ttyprintk.c:122 resync_tnc+0x1b6/0x320 drivers/net/hamradio/6pack.c:522 call_timer_fn+0x1ac/0x780 kernel/time/timer.c:1404 expire_timers kernel/time/timer.c:1449 [inline] __run_timers kernel/time/timer.c:1773 [inline] __run_timers kernel/time/timer.c:1740 [inline] run_timer_softirq+0x6c3/0x1790 kernel/time/timer.c:1786 __do_softirq+0x262/0x98c kernel/softirq.c:292 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0x19b/0x1e0 kernel/softirq.c:413 exiting_irq arch/x86/include/asm/apic.h:536 [inline] smp_apic_timer_interrupt+0x1a3/0x610 arch/x86/kernel/apic/apic.c:1137 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829 RIP: 0010:native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:61 Code: 98 81 eb f9 eb 8a cc cc cc cc cc cc e9 07 00 00 00 0f 00 2d 04 83 61 00 f4 c3 66 90 e9 07 00 00 00 0f 00 2d f4 82 61 00 fb f4 cc 55 48 89 e5 41 57 41 56 41 55 41 54 53 e8 ce 93 9b f9 e8 79 RSP: 0018:ffffffff89807ce8 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 RAX: 1ffffffff13266ae RBX: ffffffff8987a1c0 RCX: 0000000000000000 RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffffffff8987aa54 RBP: ffffffff89807d18 R08: ffffffff8987a1c0 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: dffffc0000000000 R13: ffffffff8a790e80 R14: 0000000000000000 R15: 0000000000000000 arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:690 default_idle_call+0x84/0xb0 kernel/sched/idle.c:94 cpuidle_idle_call kernel/sched/idle.c:154 [inline] do_idle+0x3c8/0x6e0 kernel/sched/idle.c:269 cpu_startup_entry+0x1b/0x20 kernel/sched/idle.c:361 rest_init+0x23b/0x371 init/main.c:451 arch_call_rest_init+0xe/0x1b start_kernel+0x904/0x943 init/main.c:784 x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:490 x86_64_start_kernel+0x77/0x7b arch/x86/kernel/head64.c:471 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:242 ------------[ cut here ]------------ WARNING: CPU: 0 PID: 0 at kernel/locking/mutex.c:737 mutex_unlock+0x1d/0x30 kernel/locking/mutex.c:744