NOHZ: local_softirq_pending 08 NOHZ: local_softirq_pending 08 NOHZ: local_softirq_pending 08 NOHZ: local_softirq_pending 08 NOHZ: local_softirq_pending 08 INFO: task getty:7234 blocked for more than 140 seconds. Not tainted 4.14.171-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. getty D28096 7234 1 0x80000002 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x7b8/0x1cd0 kernel/sched/core.c:3384 schedule+0x92/0x1c0 kernel/sched/core.c:3428 schedule_timeout+0x93b/0xe10 kernel/time/timer.c:1723 down_write_failed drivers/tty/tty_ldsem.c:298 [inline] __ldsem_down_write_nested+0x304/0x7b0 drivers/tty/tty_ldsem.c:360 ldsem_down_write+0x33/0x39 drivers/tty/tty_ldsem.c:402 __tty_ldisc_lock drivers/tty/tty_ldisc.c:332 [inline] tty_ldisc_lock+0x50/0x80 drivers/tty/tty_ldisc.c:356 tty_ldisc_hangup+0x1a6/0x5e0 drivers/tty/tty_ldisc.c:758 __tty_hangup.part.0+0x2d3/0x6d0 drivers/tty/tty_io.c:622 __tty_hangup drivers/tty/tty_io.c:572 [inline] tty_vhangup_session+0x25/0x30 drivers/tty/tty_io.c:732 disassociate_ctty.part.0+0x9b/0x6c0 drivers/tty/tty_jobctrl.c:266 disassociate_ctty+0x78/0x90 drivers/tty/tty_jobctrl.c:260 do_exit+0x17c6/0x2cd0 kernel/exit.c:856 do_group_exit+0x111/0x330 kernel/exit.c:955 SYSC_exit_group kernel/exit.c:966 [inline] SyS_exit_group+0x1d/0x20 kernel/exit.c:964 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x7f596e5e81e8 RSP: 002b:00007ffe9717e6f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f596e5e81e8 RDX: 0000000000000001 RSI: 000000000000003c RDI: 0000000000000001 RBP: 00007f596e8bd840 R08: 00000000000000e7 R09: ffffffffffffffa8 R10: 00007f596e8c3740 R11: 0000000000000246 R12: 00007f596e8bd840 R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000000 Showing all locks held in the system: 1 lock held by khungtaskd/1056: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4544 2 locks held by getty/7234: #0: (&tty->legacy_mutex){+.+.}, at: [] tty_lock+0x68/0x80 drivers/tty/tty_mutex.c:19 #1: (&tty->ldisc_sem){++++}, at: [] ldsem_down_write+0x33/0x39 drivers/tty/tty_ldsem.c:402 2 locks held by getty/7235: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156 2 locks held by getty/7236: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156 2 locks held by getty/7237: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156 2 locks held by getty/7238: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156 2 locks held by getty/7239: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156 2 locks held by getty/7240: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156 1 lock held by syz-executor.2/7539: #0: (&tty->legacy_mutex){+.+.}, at: [] tty_lock+0x68/0x80 drivers/tty/tty_mutex.c:19 1 lock held by syz-executor.2/7714: #0: (&tty->legacy_mutex){+.+.}, at: [] tty_lock+0x68/0x80 drivers/tty/tty_mutex.c:19 1 lock held by syz-executor.2/7762: #0: (&tty->legacy_mutex){+.+.}, at: [] tty_lock+0x68/0x80 drivers/tty/tty_mutex.c:19 1 lock held by syz-executor.2/7807: #0: (&tty->legacy_mutex){+.+.}, at: [] tty_lock+0x68/0x80 drivers/tty/tty_mutex.c:19 1 lock held by syz-executor.2/7845: #0: (&tty->legacy_mutex){+.+.}, at: [] tty_lock+0x68/0x80 drivers/tty/tty_mutex.c:19 1 lock held by syz-executor.2/12625: #0: (&tty->legacy_mutex){+.+.}, at: [] tty_lock+0x68/0x80 drivers/tty/tty_mutex.c:19 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1056 Comm: khungtaskd Not tainted 4.14.171-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x142/0x197 lib/dump_stack.c:58 nmi_cpu_backtrace.cold+0x57/0x94 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x141/0x189 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_all_cpu_backtrace include/linux/nmi.h:140 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline] watchdog+0x5e7/0xb90 kernel/hung_task.c:274 kthread+0x319/0x430 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 15184 Comm: syz-executor.2 Not tainted 4.14.171-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff88804a424240 task.stack: ffff8881bfce8000 RIP: 0010:__raw_callee_save___pv_queued_spin_unlock+0x1/0x17 RSP: 0018:ffff8881bfcef8a0 EFLAGS: 00000086 RAX: 1ffffffff0fe2cf9 RBX: ffff88804a424860 RCX: 1ffff11009484956 RDX: dffffc0000000000 RSI: 0000000000000003 RDI: ffff8880aed2b540 RBP: ffff8881bfcef8c8 R08: ffff88804a424240 R09: 0000000000000002 R10: 0000000000000000 R11: ffff88804a424240 R12: ffff8880aed2b540 R13: ffff8880aed2b548 R14: ffff8880aed2b550 R15: ffff8880aed2b540 FS: 00007ffbcef40700(0000) GS:ffff8880aed00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000c432dbf000 CR3: 00000001e0617000 CR4: 00000000001426e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:167 [inline] _raw_spin_unlock_irq+0x23/0x90 kernel/locking/spinlock.c:200 rq_unlock_irq kernel/sched/sched.h:1766 [inline] __schedule+0x137b/0x1cd0 kernel/sched/core.c:3387 schedule+0x92/0x1c0 kernel/sched/core.c:3428 paste_selection+0x293/0x3f2 drivers/tty/vt/selection.c:355 tioclinux+0x10e/0x400 drivers/tty/vt/vt.c:2696 vt_ioctl+0x180c/0x2170 drivers/tty/vt/vt_ioctl.c:364 tty_ioctl+0x841/0x1320 drivers/tty/tty_io.c:2661 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x7ae/0x1060 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x45c6c9 RSP: 002b:00007ffbcef3fc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007ffbcef406d4 RCX: 000000000045c6c9 RDX: 0000000020000140 RSI: 000000000000541c RDI: 0000000000000008 RBP: 000000000076bfc8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000571 R14: 00000000004c7edc R15: 000000000076bfd4 Code: ff ff 90 90 90 90 55 48 89 e5 51 52 56 57 41 50 41 51 41 52 41 53 e8 ab 11 00 00 41 5b 41 5a 41 59 41 58 5f 5e 5a 59 5d c3 90 55 <48> 89 e5 52 b8 01 00 00 00 31 d2 f0 0f b0 17 3c 01 75 03 5a 5d