INFO: task syz-executor.1:9611 blocked for more than 140 seconds.
      Not tainted 4.9.141+ #1
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.1  D29592  9611   9609 0x00000000
 ffff8801c6c94740 0000000000000000 ffff8801a7550b00 ffff8801da6b2f80
 ffff8801db721018 ffff88019a4bf840 ffffffff828075c2 ffff880100000001
 ffffffff00000000 fffffbfff08489a8 00e1c49f00000001 ffff8801db7218f0
Call Trace:
 [<ffffffff82808aef>] schedule+0x7f/0x1b0 kernel/sched/core.c:3553
 [<ffffffff828142d5>] schedule_timeout+0x735/0xe20 kernel/time/timer.c:1771
 [<ffffffff81d4312c>] down_read_failed drivers/tty/tty_ldsem.c:241 [inline]
 [<ffffffff81d4312c>] __ldsem_down_read_nested+0x33c/0x610 drivers/tty/tty_ldsem.c:332
 [<ffffffff82815952>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 [<ffffffff81d3ca85>] tty_ldisc_ref_wait+0x25/0x80 drivers/tty/tty_ldisc.c:275
 [<ffffffff81d28626>] tty_ioctl+0x3b6/0x2190 drivers/tty/tty_io.c:3009
 [<ffffffff81546dec>] vfs_ioctl fs/ioctl.c:43 [inline]
 [<ffffffff81546dec>] file_ioctl fs/ioctl.c:493 [inline]
 [<ffffffff81546dec>] do_vfs_ioctl+0x1ac/0x11a0 fs/ioctl.c:677
 [<ffffffff81547e6f>] SYSC_ioctl fs/ioctl.c:694 [inline]
 [<ffffffff81547e6f>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:685
 [<ffffffff810056ef>] do_syscall_64+0x19f/0x550 arch/x86/entry/common.c:285
 [<ffffffff82817893>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb

Showing all locks held in the system:
2 locks held by kworker/0:1/23:
 #0:  ("events"){.+.+.+}, at: [<ffffffff81130f0c>] process_one_work+0x73c/0x15f0 kernel/workqueue.c:2085
 #1:  (key_gc_work){+.+...}, at: [<ffffffff81130f44>] process_one_work+0x774/0x15f0 kernel/workqueue.c:2089
2 locks held by khungtaskd/24:
 #0:  (rcu_read_lock){......}, at: [<ffffffff8131c0cc>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff8131c0cc>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff813fe63f>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
2 locks held by getty/2017:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff82815952>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff81d37362>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142
5 locks held by kworker/u4:4/2109:
 #0:  ("%s""netns"){.+.+.+}, at: [<ffffffff81130f0c>] process_one_work+0x73c/0x15f0 kernel/workqueue.c:2085
 #1:  (net_cleanup_work){+.+.+.}, at: [<ffffffff81130f44>] process_one_work+0x774/0x15f0 kernel/workqueue.c:2089
 #2:  (net_mutex){+.+.+.}, at: [<ffffffff822e681f>] cleanup_net+0x13f/0x8b0 net/core/net_namespace.c:439
 #3:  (rtnl_mutex){+.+.+.}, at: [<ffffffff823412d7>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70
 #4:  (rcu_preempt_state.exp_mutex){+.+...}, at: [<ffffffff8124a749>] exp_funnel_lock kernel/rcu/tree_exp.h:256 [inline]
 #4:  (rcu_preempt_state.exp_mutex){+.+...}, at: [<ffffffff8124a749>] _synchronize_rcu_expedited+0x339/0x840 kernel/rcu/tree_exp.h:569
2 locks held by kworker/1:3/3854:
 #0:  ("events"){.+.+.+}, at: [<ffffffff81130f0c>] process_one_work+0x73c/0x15f0 kernel/workqueue.c:2085
 #1:  ((&rew.rew_work)){+.+...}, at: [<ffffffff81130f44>] process_one_work+0x774/0x15f0 kernel/workqueue.c:2089
2 locks held by syz-executor.1/9609:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff82815952>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff81d37362>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142
1 lock held by syz-executor.1/9611:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff82815952>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
2 locks held by syz-executor.3/13941:
 #0:  (sk_lock-AF_PACKET){+.+.+.}, at: [<ffffffff827d1f3f>] lock_sock include/net/sock.h:1404 [inline]
 #0:  (sk_lock-AF_PACKET){+.+.+.}, at: [<ffffffff827d1f3f>] packet_setsockopt+0x50f/0x2630 net/packet/af_packet.c:3668
 #1:  (rcu_preempt_state.exp_mutex){+.+...}, at: [<ffffffff8124a7b7>] exp_funnel_lock kernel/rcu/tree_exp.h:289 [inline]
 #1:  (rcu_preempt_state.exp_mutex){+.+...}, at: [<ffffffff8124a7b7>] _synchronize_rcu_expedited+0x3a7/0x840 kernel/rcu/tree_exp.h:569

=============================================

NMI backtrace for cpu 0
CPU: 0 PID: 24 Comm: khungtaskd Not tainted 4.9.141+ #1
 ffff8801d9907d08 ffffffff81b42e79 0000000000000000 0000000000000000
 0000000000000000 0000000000000001 ffffffff810983b0 ffff8801d9907d40
 ffffffff81b4df89 0000000000000000 0000000000000000 0000000000000002
Call Trace:
 [<ffffffff81b42e79>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81b42e79>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81b4df89>] nmi_cpu_backtrace.cold.0+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81b4df1c>] nmi_trigger_cpumask_backtrace+0x12c/0x151 lib/nmi_backtrace.c:60
 [<ffffffff810984b4>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff8131c65d>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff8131c65d>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff8131c65d>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff8131c65d>] watchdog+0x6ad/0xa20 kernel/hung_task.c:239
 [<ffffffff81142c3d>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff82817a5c>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 13936 Comm: syz-executor.3 Not tainted 4.9.141+ #1
task: ffff88019bcf2f80 task.stack: ffff8801d74c8000
RIP: 0010:[<ffffffff81243be7>] 
c [<ffffffff81243be7>] debug_lockdep_rcu_enabled.part.0+0x37/0x60 kernel/rcu/update.c:265
RSP: 0018:ffff8801d74cf910  EFLAGS: 00000202
RAX: 0000000000000007 RBX: ffff88019bcf2f80 RCX: 0000000000000002
RDX: 0000000000000000 RSI: ffff8801cd6a8170 RDI: ffff88019bcf382c
RBP: ffff8801d74cf918 R08: 000000000000000d R09: ffff8801d74cf6c8
R10: ffffffff815ae043 R11: ffff8801d74cf667 R12: ffff8801da4013c0
R13: 00000000024080c0 R14: 0000000000000100 R15: ffff8800bb54f140
FS:  00007fc965cf9700(0000) GS:ffff8801db700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2de28000 CR3: 00000001ce783000 CR4: 00000000001606b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff831f2500
c ffff8801d74cf930
c ffffffff81243dfc
c 0000000000000140
c
 ffff8801d74cf978
c ffffffff814ee462
c 0000000000000732
c ffffffff815ae043
c
 0000000000000100
c 0000000000000004
c dffffc0000000000
c ffff8801cef81180
c
Call Trace:
 [<ffffffff81243dfc>] debug_lockdep_rcu_enabled kernel/rcu/update.c:264 [inline]
 [<ffffffff81243dfc>] rcu_read_lock_sched_held+0x7c/0x120 kernel/rcu/update.c:105
 [<ffffffff814ee462>] trace_kmalloc include/trace/events/kmem.h:45 [inline]
 [<ffffffff814ee462>] __kmalloc+0x2a2/0x310 mm/slub.c:3739
 [<ffffffff815ae043>] kmalloc_array include/linux/slab.h:582 [inline]
 [<ffffffff815ae043>] kcalloc include/linux/slab.h:593 [inline]
 [<ffffffff815ae043>] iter_file_splice_write+0x143/0xb30 fs/splice.c:711
 [<ffffffff815a9ab8>] do_splice_from fs/splice.c:870 [inline]
 [<ffffffff815a9ab8>] direct_splice_actor+0x128/0x190 fs/splice.c:1037
 [<ffffffff815ab6c1>] splice_direct_to_actor+0x2c1/0x7e0 fs/splice.c:992
 [<ffffffff815abd83>] do_splice_direct+0x1a3/0x270 fs/splice.c:1080
 [<ffffffff8150d780>] do_sendfile+0x4f0/0xc30 fs/read_write.c:1393
 [<ffffffff8150f7f1>] SYSC_sendfile64 fs/read_write.c:1448 [inline]
 [<ffffffff8150f7f1>] SyS_sendfile64+0xd1/0x160 fs/read_write.c:1440
 [<ffffffff810056ef>] do_syscall_64+0x19f/0x550 arch/x86/entry/common.c:285
 [<ffffffff82817893>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Code: 
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c