INFO: task syz-executor7:8692 blocked for more than 120 seconds.
      Not tainted 4.9.70-gc14c7b3 #110
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor7   D29568  8692   3521 0x00000004
 ffff8801b7818000 ffff8801cf954000 ffff8801cb76b9c0 ffff8801b5fd3000
 ffff8801db221458 ffff8801b6bdf7d0 ffffffff83898c3b ffff8801b6bdf7a8
 ffffffff8123886f 00ffffff838a45aa ffff8801db221d28 ffff8801db221d50
Call Trace:
 [<ffffffff8389a1df>] schedule+0x7f/0x1b0 kernel/sched/core.c:3550
 [<ffffffff838a46c0>] rwsem_down_read_failed+0x1e0/0x320 kernel/locking/rwsem-xadd.c:260
 [<ffffffff81dc3dd8>] call_rwsem_down_read_failed+0x18/0x30 arch/x86/lib/rwsem.S:94
 [<ffffffff838a3442>] __down_read arch/x86/include/asm/rwsem.h:65 [inline]
 [<ffffffff838a3442>] down_read+0x52/0xb0 kernel/locking/rwsem.c:24
 [<ffffffff820022c7>] n_tty_read+0x217/0x16c0 drivers/tty/n_tty.c:2137
 [<ffffffff81ff0b19>] tty_read+0x169/0x250 drivers/tty/tty_io.c:1079
 [<ffffffff81569121>] do_loop_readv_writev.part.17+0x141/0x1e0 fs/read_write.c:714
 [<ffffffff8156cf90>] do_loop_readv_writev fs/read_write.c:880 [inline]
 [<ffffffff8156cf90>] do_readv_writev+0x520/0x750 fs/read_write.c:874
 [<ffffffff8156d244>] vfs_readv+0x84/0xc0 fs/read_write.c:898
 [<ffffffff8156d366>] do_readv+0xe6/0x250 fs/read_write.c:924
 [<ffffffff81570857>] SYSC_readv fs/read_write.c:1011 [inline]
 [<ffffffff81570857>] SyS_readv+0x27/0x30 fs/read_write.c:1008
 [<ffffffff838aa405>] entry_SYSCALL_64_fastpath+0x23/0xc6

Showing all locks held in the system:
2 locks held by khungtaskd/514:
 #0:  (rcu_read_lock){......}, at: [<ffffffff8136fe45>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff8136fe45>] watchdog+0x125/0xa70 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff812355e0>] debug_show_all_locks+0x70/0x280 kernel/locking/lockdep.c:4336
2 locks held by getty/3305:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff838a8602>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+.+.}, at: [<ffffffff820022a4>] n_tty_read+0x1f4/0x16c0 drivers/tty/n_tty.c:2133
3 locks held by syz-executor7/8692:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff838a8602>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+.+.}, at: [<ffffffff820022a4>] n_tty_read+0x1f4/0x16c0 drivers/tty/n_tty.c:2133
 #2:  (&o_tty->termios_rwsem/1){++++.+}, at: [<ffffffff820022c7>] n_tty_read+0x217/0x16c0 drivers/tty/n_tty.c:2137
2 locks held by syz-executor7/8716:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff838a8602>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&o_tty->termios_rwsem/1){++++.+}, at: [<ffffffff8200aa35>] set_termios+0xf5/0x670 drivers/tty/tty_ioctl.c:592

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

NMI backtrace for cpu 0
CPU: 0 PID: 514 Comm: khungtaskd Not tainted 4.9.70-gc14c7b3 #110
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d9b87d00 ffffffff81d90c49 0000000000000000 0000000000000000
 0000000000000000 0000000000000001 ffffffff810ba1a0 ffff8801d9b87d38
 ffffffff81d9bd6d 0000000000000000 0000000000000000 ffff8801c9330418
Call Trace:
 [<ffffffff81d90c49>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81d90c49>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81d9bd6d>] nmi_cpu_backtrace+0xfd/0x120 lib/nmi_backtrace.c:99
 [<ffffffff81d9bea7>] nmi_trigger_cpumask_backtrace+0x117/0x190 lib/nmi_backtrace.c:60
 [<ffffffff810ba294>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff81370410>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81370410>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81370410>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81370410>] watchdog+0x6f0/0xa70 kernel/hung_task.c:239
 [<ffffffff811985ed>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff838aa6aa>] ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:433
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 8667 Comm: syz-executor7 Not tainted 4.9.70-gc14c7b3 #110
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801b793b000 task.stack: ffff8801b6590000
RIP: 0010:[<ffffffff813681d0>] 
c [<ffffffff813681d0>] __sanitizer_cov_trace_pc+0x0/0x50
RSP: 0018:ffff8801b6597b30  EFLAGS: 00000202
RAX: 0000000000000eab RBX: ffffc90006106060 RCX: ffffffff81fff69c
RDX: 0000000000010000 RSI: ffffc90000a40000 RDI: ffffc90006107260
RBP: ffff8801b6597b78 R08: 1ffff10036f2771a R09: 0000000000000000
R10: 0000000000000003 R11: ffff8801b793b000 R12: ffffc90006105000
R13: 000000078387ceab R14: 00000000207d0ffc R15: ffff8801c6ff2cb8
FS:  00007f9781a84700(0000) GS:ffff8801db30000