INFO: task syz-executor556:2016 blocked for more than 140 seconds. Not tainted 4.14.81+ #6 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor556 D29656 2016 1 0x00000000 Call Trace: schedule+0x7f/0x1b0 kernel/sched/core.c:3490 schedule_timeout+0x710/0xe60 kernel/time/timer.c:1721 down_read_failed drivers/tty/tty_ldsem.c:242 [inline] __ldsem_down_read_nested+0x2ca/0x5b0 drivers/tty/tty_ldsem.c:332 tty_ldisc_ref_wait+0x20/0x80 drivers/tty/tty_ldisc.c:275 tty_ioctl+0x4cb/0x13e0 drivers/tty/tty_io.c:2654 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x1a0/0x1030 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x7e/0xb0 fs/ioctl.c:692 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x440e79 RSP: 002b:00007ffed6d2fc48 EFLAGS: 00000217 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000440e79 RDX: 0000000020000000 RSI: 0000000000001261 RDI: 0000000000000002 RBP: 0000000000000000 R08: 00000000004002c8 R09: 00000000004002c8 R10: 00000000ffffffff R11: 0000000000000217 R12: 000000000005cf10 R13: 0000000000401e50 R14: 0000000000000000 R15: 0000000000000000 INFO: task syz-executor556:2041 blocked for more than 140 seconds. Not tainted 4.14.81+ #6 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor556 D29656 2041 1 0x00000000 Call Trace: schedule+0x7f/0x1b0 kernel/sched/core.c:3490 schedule_timeout+0x710/0xe60 kernel/time/timer.c:1721 down_read_failed drivers/tty/tty_ldsem.c:242 [inline] __ldsem_down_read_nested+0x2ca/0x5b0 drivers/tty/tty_ldsem.c:332 tty_ldisc_ref_wait+0x20/0x80 drivers/tty/tty_ldisc.c:275 tty_ioctl+0x4cb/0x13e0 drivers/tty/tty_io.c:2654 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x1a0/0x1030 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x7e/0xb0 fs/ioctl.c:692 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x440e79 RSP: 002b:00007ffed6d2fc48 EFLAGS: 00000217 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000440e79 RDX: 0000000020000000 RSI: 0000000000001261 RDI: 0000000000000004 RBP: 0000000000000000 R08: 00000000004002c8 R09: 00000000004002c8 R10: 00000000ffffffff R11: 0000000000000217 R12: 000000000005cf1e R13: 0000000000401e50 R14: 0000000000000000 R15: 0000000000000000 INFO: task syz-executor556:2092 blocked for more than 140 seconds. Not tainted 4.14.81+ #6 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor556 D28712 2092 1 0x00000004 Call Trace: schedule+0x7f/0x1b0 kernel/sched/core.c:3490 schedule_timeout+0x710/0xe60 kernel/time/timer.c:1721 down_read_failed drivers/tty/tty_ldsem.c:242 [inline] __ldsem_down_read_nested+0x2ca/0x5b0 drivers/tty/tty_ldsem.c:332 tty_ldisc_ref_wait+0x20/0x80 drivers/tty/tty_ldisc.c:275 tty_ioctl+0x4cb/0x13e0 drivers/tty/tty_io.c:2654 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x1a0/0x1030 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x7e/0xb0 fs/ioctl.c:692 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x440e79 RSP: 002b:00007ffed6d2fc48 EFLAGS: 00000207 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000440e79 RDX: 0000000020000000 RSI: 0000000000001261 RDI: 0000000000000005 RBP: 0000000000000000 R08: 00000000004002c8 R09: 00000000004002c8 R10: 00000000004002c8 R11: 0000000000000207 R12: 000000000005cf6e R13: 0000000000401e50 R14: 0000000000000000 R15: 0000000000000000 INFO: task syz-executor556:2162 blocked for more than 140 seconds. Not tainted 4.14.81+ #6 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor556 D29656 2162 1 0x00000000 Call Trace: schedule+0x7f/0x1b0 kernel/sched/core.c:3490 schedule_timeout+0x710/0xe60 kernel/time/timer.c:1721 down_read_failed drivers/tty/tty_ldsem.c:242 [inline] __ldsem_down_read_nested+0x2ca/0x5b0 drivers/tty/tty_ldsem.c:332 tty_ldisc_ref_wait+0x20/0x80 drivers/tty/tty_ldisc.c:275 tty_ioctl+0x4cb/0x13e0 drivers/tty/tty_io.c:2654 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x1a0/0x1030 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x7e/0xb0 fs/ioctl.c:692 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x440e79 RSP: 002b:00007ffed6d2fc48 EFLAGS: 00000217 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000440e79 RDX: 0000000020000000 RSI: 0000000000001261 RDI: 0000000000000004 RBP: 0000000000000000 R08: 0000000b004002c8 R09: 0000000b004002c8 R10: 00000000ffffffff R11: 0000000000000217 R12: 000000000005d0cd R13: 0000000000401e50 R14: 0000000000000000 R15: 0000000000000000 INFO: task syz-executor556:2368 blocked for more than 140 seconds. Not tainted 4.14.81+ #6 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor556 D29752 2368 1 0x00000000 Call Trace: schedule+0x7f/0x1b0 kernel/sched/core.c:3490 schedule_timeout+0x710/0xe60 kernel/time/timer.c:1721 down_read_failed drivers/tty/tty_ldsem.c:242 [inline] __ldsem_down_read_nested+0x2ca/0x5b0 drivers/tty/tty_ldsem.c:332 tty_ldisc_ref_wait+0x20/0x80 drivers/tty/tty_ldisc.c:275 tty_ioctl+0x4cb/0x13e0 drivers/tty/tty_io.c:2654 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x1a0/0x1030 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x7e/0xb0 fs/ioctl.c:692 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x440e79 RSP: 002b:00007ffed6d2fc48 EFLAGS: 00000203 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000440e79 RDX: 0000000020000000 RSI: 0000000000001261 RDI: 0000000000000002 RBP: 0000000000000000 R08: 00000000004002c8 R09: 00000000004002c8 R10: 00000000004002c8 R11: 0000000000000203 R12: 000000000005e1ac R13: 0000000000401e50 R14: 0000000000000000 R15: 0000000000000000 Showing all locks held in the system: 1 lock held by khungtaskd/23: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x74/0x20f kernel/locking/lockdep.c:4541 2 locks held by getty/1762: #0: (&tty->ldisc_sem){++++}, at: [] tty_ldisc_ref_wait+0x20/0x80 drivers/tty/tty_ldisc.c:275 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1ff/0x15e0 drivers/tty/n_tty.c:2142 2 locks held by syz-executor556/2013: #0: (&tty->ldisc_sem){++++}, at: [] tty_ldisc_ref_wait+0x20/0x80 drivers/tty/tty_ldisc.c:275 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1ff/0x15e0 drivers/tty/n_tty.c:2142 1 lock held by syz-executor556/2016: #0: (&tty->ldisc_sem){++++}, at: [] tty_ldisc_ref_wait+0x20/0x80 drivers/tty/tty_ldisc.c:275 2 locks held by syz-executor556/2037: #0: (&tty->ldisc_sem){++++}, at: [] tty_ldisc_ref_wait+0x20/0x80 drivers/tty/tty_ldisc.c:275 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1ff/0x15e0 drivers/tty/n_tty.c:2142 1 lock held by syz-executor556/2041: #0: (&tty->ldisc_sem){++++}, at: [] tty_ldisc_ref_wait+0x20/0x80 drivers/tty/tty_ldisc.c:275 1 lock held by syz-executor556/2092: #0: (&tty->ldisc_sem){++++}, at: [] tty_ldisc_ref_wait+0x20/0x80 drivers/tty/tty_ldisc.c:275 2 locks held by syz-executor556/2098: #0: (&tty->ldisc_sem){++++}, at: [] tty_ldisc_ref_wait+0x20/0x80 drivers/tty/tty_ldisc.c:275 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1ff/0x15e0 drivers/tty/n_tty.c:2142 2 locks held by syz-executor556/2153: #0: (&tty->ldisc_sem){++++}, at: [] tty_ldisc_ref_wait+0x20/0x80 drivers/tty/tty_ldisc.c:275 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1ff/0x15e0 drivers/tty/n_tty.c:2142 1 lock held by syz-executor556/2162: #0: (&tty->ldisc_sem){++++}, at: [] tty_ldisc_ref_wait+0x20/0x80 drivers/tty/tty_ldisc.c:275 2 locks held by syz-executor556/2181: #0: (&tty->ldisc_sem){++++}, at: [] tty_ldisc_ref_wait+0x20/0x80 drivers/tty/tty_ldisc.c:275 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1ff/0x15e0 drivers/tty/n_tty.c:2142 1 lock held by syz-executor556/2368: #0: (&tty->ldisc_sem){++++}, at: [] tty_ldisc_ref_wait+0x20/0x80 drivers/tty/tty_ldisc.c:275 2 locks held by syz-executor556/2369: #0: (&tty->ldisc_sem){++++}, at: [] tty_ldisc_ref_wait+0x20/0x80 drivers/tty/tty_ldisc.c:275 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1ff/0x15e0 drivers/tty/n_tty.c:2142 1 lock held by syz-executor556/3498: #0: (&tty->ldisc_sem){++++}, at: [] tty_ldisc_ref_wait+0x20/0x80 drivers/tty/tty_ldisc.c:275 1 lock held by syz-executor556/3503: #0: (&tty->ldisc_sem){++++}, at: [] tty_ldisc_ref_wait+0x20/0x80 drivers/tty/tty_ldisc.c:275 2 locks held by syz-executor556/3504: #0: (&tty->ldisc_sem){++++}, at: [] tty_ldisc_ref_wait+0x20/0x80 drivers/tty/tty_ldisc.c:275 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1ff/0x15e0 drivers/tty/n_tty.c:2142 2 locks held by syz-executor556/3505: #0: (&tty->legacy_mutex){+.+.}, at: [] tty_lock+0x5d/0x70 drivers/tty/tty_mutex.c:19 #1: (&tty->ldisc_sem){++++}, at: [] __tty_ldisc_lock drivers/tty/tty_ldisc.c:323 [inline] #1: (&tty->ldisc_sem){++++}, at: [] tty_ldisc_lock+0x19/0x40 drivers/tty/tty_ldisc.c:342 1 lock held by syz-executor556/3508: #0: (&tty->ldisc_sem){++++}, at: [] tty_ldisc_ref_wait+0x20/0x80 drivers/tty/tty_ldisc.c:275 2 locks held by syz-executor556/3509: #0: (&tty->legacy_mutex){+.+.}, at: [] tty_lock+0x5d/0x70 drivers/tty/tty_mutex.c:19 #1: (&tty->ldisc_sem){++++}, at: [] __tty_ldisc_lock drivers/tty/tty_ldisc.c:323 [inline] #1: (&tty->ldisc_sem){++++}, at: [] tty_ldisc_lock+0x19/0x40 drivers/tty/tty_ldisc.c:342 2 locks held by syz-executor556/3510: #0: (&tty->ldisc_sem){++++}, at: [] tty_ldisc_ref_wait+0x20/0x80 drivers/tty/tty_ldisc.c:275 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1ff/0x15e0 drivers/tty/n_tty.c:2142 1 lock held by syz-executor556/3513: #0: (&tty->ldisc_sem){++++}, at: [] tty_ldisc_ref_wait+0x20/0x80 drivers/tty/tty_ldisc.c:275 2 locks held by syz-executor556/3514: #0: (&tty->ldisc_sem){++++}, at: [] tty_ldisc_ref_wait+0x20/0x80 drivers/tty/tty_ldisc.c:275 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1ff/0x15e0 drivers/tty/n_tty.c:2142 2 locks held by syz-executor556/3515: #0: (&tty->legacy_mutex){+.+.}, at: [] tty_lock+0x5d/0x70 drivers/tty/tty_mutex.c:19 #1: (&tty->ldisc_sem){++++}, at: [] __tty_ldisc_lock drivers/tty/tty_ldisc.c:323 [inline] #1: (&tty->ldisc_sem){++++}, at: [] tty_ldisc_lock+0x19/0x40 drivers/tty/tty_ldisc.c:342 1 lock held by syz-executor556/3518: #0: (&tty->ldisc_sem){++++}, at: [] tty_ldisc_ref_wait+0x20/0x80 drivers/tty/tty_ldisc.c:275 2 locks held by syz-executor556/3519: #0: (&tty->ldisc_sem){++++}, at: [] tty_ldisc_ref_wait+0x20/0x80 drivers/tty/tty_ldisc.c:275 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1ff/0x15e0 drivers/tty/n_tty.c:2142 2 locks held by syz-executor556/3520: #0: (&tty->legacy_mutex){+.+.}, at: [] tty_lock+0x5d/0x70 drivers/tty/tty_mutex.c:19 #1: (&tty->ldisc_sem){++++}, at: [] __tty_ldisc_lock drivers/tty/tty_ldisc.c:323 [inline] #1: (&tty->ldisc_sem){++++}, at: [] tty_ldisc_lock+0x19/0x40 drivers/tty/tty_ldisc.c:342 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 23 Comm: khungtaskd Not tainted 4.14.81+ #6 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0xb9/0x11b lib/dump_stack.c:53 nmi_cpu_backtrace.cold.0+0x47/0x85 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x121/0x146 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:138 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:196 [inline] watchdog+0x574/0xa70 kernel/hung_task.c:252 kthread+0x348/0x420 kernel/kthread.c:232 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:402 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 2183 Comm: syz-executor556 Not tainted 4.14.81+ #6 task: ffff8801cb1a9780 task.stack: ffff8801cb0f0000 RIP: 0010:entry_SYSCALL_64_after_hwframe+0x4b/0xb7 RSP: 0018:ffff8801cb0f7f58 EFLAGS: 00000097 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 1ffff100396352f1 RSI: 0000000000000000 RDI: ffff8801cb1a9788 RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000d38880(0000) GS:ffff8801dba00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fffa72c5e30 CR3: 00000001cb21e005 CR4: 00000000001606b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: RIP: 0033:0x400f7a RSP: 002b:00007ffed6d2fad8 EFLAGS: 00000246 ORIG_RAX: 000000000000003d RAX: fffffffffffffff6 RBX: 00000000ffffffff RCX: 0000000000400f7a RDX: 0000000040000000 RSI: 00007ffed6d2fc54 RDI: ffffffffffffffff RBP: 0000000000000003 R08: 00000000004002c8 R09: 00000000004002c8 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffed6d2fc54 R13: 00000000ffffffff R14: 0000000000000000 R15: 0000000000000000 Code: ed 41 54 45 31 e4 41 55 45 31 ed 41 56 45 31 f6 41 57 45 31 ff e8 e7 20 60 fe 48 89 e7 e8 5a 4f 60 fe 0f ba a4 24 90 00 00 00 09 <73> 05 e8 b3 20 60 fe 48 8b 4c 24 58 4c 8b 9c 24 80 00 00 00 49