INFO: task getty:7293 blocked for more than 140 seconds. Not tainted 4.14.166-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. getty D25920 7293 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: 0033:0x7f992f0761e8 RSP: 002b:00007ffe59547138 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f992f0761e8 RDX: 0000000000000001 RSI: 000000000000003c RDI: 0000000000000001 RBP: 00007f992f34b840 R08: 00000000000000e7 R09: ffffffffffffffa8 R10: 00007f992f351740 R11: 0000000000000246 R12: 00007f992f34b840 R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000000 INFO: task kworker/u4:5:7420 blocked for more than 140 seconds. Not tainted 4.14.166-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/u4:5 D25712 7420 2 0x80000000 Workqueue: events_unbound flush_to_ldisc 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_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 flush_to_ldisc+0x39/0x400 drivers/tty/tty_buffer.c:499 process_one_work+0x863/0x1600 kernel/workqueue.c:2114 worker_thread+0x5d9/0x1050 kernel/workqueue.c:2248 kthread+0x319/0x430 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 INFO: task syz-executor.5:18340 blocked for more than 140 seconds. Not tainted 4.14.166-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D28384 18340 15975 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_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 tty_lock+0x68/0x80 drivers/tty/tty_mutex.c:19 tty_release+0xaa/0xd60 drivers/tty/tty_io.c:1652 __fput+0x275/0x7a0 fs/file_table.c:210 ____fput+0x16/0x20 fs/file_table.c:244 task_work_run+0x114/0x190 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0xa1a/0x2cd0 kernel/exit.c:858 do_group_exit+0x111/0x330 kernel/exit.c:955 get_signal+0x381/0x1cd0 kernel/signal.c:2413 do_signal+0x86/0x19a0 arch/x86/kernel/signal.c:814 exit_to_usermode_loop+0x15c/0x220 arch/x86/entry/common.c:160 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline] syscall_return_slowpath arch/x86/entry/common.c:270 [inline] do_syscall_64+0x4bc/0x640 arch/x86/entry/common.c:297 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x45b349 RSP: 002b:00007feab350ecf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 000000000075bf28 RCX: 000000000045b349 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000075bf28 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000075bf2c R13: 00007ffdfceddbbf R14: 00007feab350f9c0 R15: 000000000075bf2c Showing all locks held in the system: 1 lock held by khungtaskd/1057: #0: (tasklist_lock){.+.?}, at: [] debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4544 1 lock held by rsyslogd/7170: #0: (&f->f_pos_lock){+.+.}, at: [] __fdget_pos+0xab/0xd0 fs/file.c:769 2 locks held by getty/7293: #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/7294: #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/7295: #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/7296: #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/7297: #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/7298: #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/7299: #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 3 locks held by kworker/u4:5/7420: #0: ("events_unbound"){+.+.}, at: [] work_static include/linux/workqueue.h:199 [inline] #0: ("events_unbound"){+.+.}, at: [] set_work_data kernel/workqueue.c:619 [inline] #0: ("events_unbound"){+.+.}, at: [] set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline] #0: ("events_unbound"){+.+.}, at: [] process_one_work+0x76e/0x1600 kernel/workqueue.c:2085 #1: ((&buf->work)){+.+.}, at: [] process_one_work+0x7ab/0x1600 kernel/workqueue.c:2089 #2: (&buf->lock){+.+.}, at: [] flush_to_ldisc+0x39/0x400 drivers/tty/tty_buffer.c:499 1 lock held by syz-executor.5/18340: #0: (&tty->legacy_mutex){+.+.}, at: [] tty_lock+0x68/0x80 drivers/tty/tty_mutex.c:19 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1057 Comm: khungtaskd Not tainted 4.14.166-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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 22 Comm: kworker/u4:1 Not tainted 4.14.166-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bat_events batadv_purge_orig task: ffff8880a9ec05c0 task.stack: ffff8880a9ec8000 RIP: 0010:__local_bh_enable_ip+0x0/0x1a0 kernel/softirq.c:164 RSP: 0018:ffff8880a9ecfc68 EFLAGS: 00000246 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 1ffff110153d81c6 RDX: dffffc0000000000 RSI: 0000000000000201 RDI: ffffffff86520f80 RBP: ffff8880a9ecfc78 R08: ffff8880a9ec05c0 R09: 0000000000000002 R10: 0000000000000000 R11: ffff8880a9ec05c0 R12: ffff888067453890 R13: dffffc0000000000 R14: ffff8880a9dfec00 R15: ffff8880aa81c8c0 FS: 0000000000000000(0000) GS:ffff8880aec00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000001bf3000 CR3: 000000009ae51000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: spin_unlock_bh include/linux/spinlock.h:362 [inline] _batadv_purge_orig+0xa90/0xfb0 net/batman-adv/originator.c:1325 batadv_purge_orig+0x1b/0x70 net/batman-adv/originator.c:1338 process_one_work+0x863/0x1600 kernel/workqueue.c:2114 worker_thread+0x5d9/0x1050 kernel/workqueue.c:2248 kthread+0x319/0x430 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Code: 57 cd 4e 00 e9 32 ff ff ff 48 c7 c7 50 69 f1 87 e8 46 cd 4e 00 e9 d7 fe ff ff e8 dc cd 4e 00 eb aa 66 2e 0f 1f 84 00 00 00 00 00 <55> 48 89 e5 41 54 49 89 fc 53 89 f3 65 8b 05 2d 07 c9 7e a9 00