sd 0:0:1:0: [sg0] tag#932 CDB[10]: 0c 95 28 08 be c3 ca d6 48 ab 84 8b b2 c7 ec 63
sd 0:0:1:0: [sg0] tag#932 CDB[20]: f4
INFO: task syz-executor2:10323 blocked for more than 120 seconds.
      Not tainted 4.9.109-g7cecc75 #2
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor2   D28984 10323   3845 0x00000004
 ffff8801cf234800 0000000000000000 ffff88016f245f80 ffff8801d56c3000
 ffff8801db221c18 ffff8801d95e7568 ffffffff839e8a3d ffffffff812355f7
 0000000000000000 ffff8801cf2350c0 0000000600000007 ffff8801db2224e8
Call Trace:
 [<ffffffff839ea03f>] schedule+0x7f/0x1b0 kernel/sched/core.c:3557
 [<ffffffff839f5678>] __rwsem_down_write_failed_common kernel/locking/rwsem-xadd.c:526 [inline]
 [<ffffffff839f5678>] rwsem_down_write_failed+0x598/0x990 kernel/locking/rwsem-xadd.c:555
 [<ffffffff81ee8107>] call_rwsem_down_write_failed+0x17/0x30 arch/x86/lib/rwsem.S:105
 [<ffffffff839f344c>] __down_write arch/x86/include/asm/rwsem.h:125 [inline]
 [<ffffffff839f344c>] down_write+0x5c/0xa0 kernel/locking/rwsem.c:54
 [<ffffffff821281e7>] tty_set_termios+0xe7/0x8a0 drivers/tty/tty_ioctl.c:549
 [<ffffffff8212978f>] set_termios+0x38f/0x620 drivers/tty/tty_ioctl.c:635
 [<ffffffff8212a17b>] tty_mode_ioctl+0x75b/0x980 drivers/tty/tty_ioctl.c:1002
 [<ffffffff8212a444>] n_tty_ioctl_helper+0x44/0x370 drivers/tty/tty_ioctl.c:1161
 [<ffffffff8211d586>] n_tty_ioctl+0x46/0x2c0 drivers/tty/n_tty.c:2443
 [<ffffffff82116934>] tty_ioctl+0x5a4/0x2270 drivers/tty/tty_io.c:3009
 [<ffffffff815b2b9c>] vfs_ioctl fs/ioctl.c:43 [inline]
 [<ffffffff815b2b9c>] file_ioctl fs/ioctl.c:493 [inline]
 [<ffffffff815b2b9c>] do_vfs_ioctl+0x1ac/0x11a0 fs/ioctl.c:677
 [<ffffffff815b3c1f>] SYSC_ioctl fs/ioctl.c:694 [inline]
 [<ffffffff815b3c1f>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:685
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839f9913>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb

Showing all locks held in the system:
2 locks held by khungtaskd/519:
 #0:  (rcu_read_lock){......}, at: [<ffffffff8136662c>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff8136662c>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff81425cb7>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
2 locks held by getty/3772:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff839f7ae2>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff8211fce2>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2133
2 locks held by syz-executor2/10323:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff839f7ae2>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&o_tty->termios_rwsem/1){++++..}, at: [<ffffffff821281e7>] tty_set_termios+0xe7/0x8a0 drivers/tty/tty_ioctl.c:549

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

NMI backtrace for cpu 0
CPU: 0 PID: 519 Comm: khungtaskd Not tainted 4.9.109-g7cecc75 #2
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d844fd08 ffffffff81eb3e29 0000000000000000 0000000000000000
 0000000000000000 0000000000000001 ffffffff810b9580 ffff8801d844fd40
 ffffffff81ebf127 0000000000000000 0000000000000000 0000000000000002
Call Trace:
 [<ffffffff81eb3e29>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81eb3e29>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81ebf127>] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81ebf0ba>] nmi_trigger_cpumask_backtrace+0x12a/0x14f lib/nmi_backtrace.c:60
 [<ffffffff810b9684>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff81366bc4>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81366bc4>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81366bc4>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81366bc4>] watchdog+0x6b4/0xa20 kernel/hung_task.c:239
 [<ffffffff8119d04d>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff839f9adc>] 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: 22 Comm: kworker/u4:1 Not tainted 4.9.109-g7cecc75 #2
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events_unbound flush_to_ldisc
c
task: ffff8801d9aeb000 task.stack: ffff8801d9bd0000
RIP: 0010:[<ffffffff8135e960>] 
c [<ffffffff8135e960>] check_kcov_mode kernel/kcov.c:66 [inline]
RIP: 0010:[<ffffffff8135e960>] 
c [<ffffffff8135e960>] __sanitizer_cov_trace_pc+0x20/0x50 kernel/kcov.c:100
RSP: 0018:ffff8801d9bd79c8  EFLAGS: 00000246
RAX: ffff8801d9aeb000 RBX: ffffc90012807000 RCX: 0000000000000002
RDX: 0000000000000000 RSI: ffffffff8211bb8f RDI: ffffc900128089e2
RBP: ffff8801d9bd79c8 R08: ffff8801d9aeb9b0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 00000006e8e20783
R13: 00000000000fcc7a R14: dffffc0000000000 R15: 00000006e8e20783
FS:  0000000000000000(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c446fb1000 CR3: 00000001c575c000 CR4: 00000000001606f0
DR0: 0000000020000000 DR1: 0000000020000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Stack:
 ffff8801d9bd7a40
c ffffffff8211bb8f
c 0000000000000246
c ffff8801d9bd79f8
c
 ffffc90012809278
c ffffed0039928b15
c ffff8801cc9458ac
c ffffc90012807020
c
 0000000000000000
c ffff8801cc945500
c ffffc90012809300
c ffffc90012807000
c
Call Trace:
 [<ffffffff8211bb8f>] echo_buf drivers/tty/n_tty.c:146 [inline]
 [<ffffffff8211bb8f>] __process_echoes+0x5cf/0x780 drivers/tty/n_tty.c:734
 [<ffffffff821255c4>] flush_echoes drivers/tty/n_tty.c:801 [inline]
 [<ffffffff821255c4>] __receive_buf drivers/tty/n_tty.c:1617 [inline]
 [<ffffffff821255c4>] n_tty_receive_buf_common+0xd34/0x2300 drivers/tty/n_tty.c:1711
 [<ffffffff82126bc3>] n_tty_receive_buf2+0x33/0x40 drivers/tty/n_tty.c:1746
 [<ffffffff8212c6bf>] tty_ldisc_receive_buf+0xaf/0x190 drivers/tty/tty_buffer.c:455
 [<ffffffff8212d6c3>] receive_buf drivers/tty/tty_buffer.c:474 [inline]
 [<ffffffff8212d6c3>] flush_to_ldisc+0x253/0x370 drivers/tty/tty_buffer.c:533
 [<ffffffff8118d121>] process_one_work+0x7e1/0x1500 kernel/workqueue.c:2092
 [<ffffffff8118df16>] worker_thread+0xd6/0x10a0 kernel/workqueue.c:2226
 [<ffffffff8119d04d>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff839f9adc>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373
Code: 
c0f 
c1f 
c84 
c00 
c00 
c00 
c00 
c00 
c0f 
c1f 
c00 
c55 
c48 
c89 
ce5 
c65 
c48 
c8b 
c04 
c25 
cc0 
c7d 
c01 
c00 
c65 
c8b 
c15 
cfc 
c93 
ccb 
c7e 
c81 
ce2 
c00 
c01 
c1f 
c00 
c48 
c8b 
c75 
c08 
c75 
c2b 
c<8b> 
c90 
c80 
c12 
c00 
c00 
c83 
cfa 
c02 
c75 
c20 
c48 
c8b 
c88 
c88 
c12 
c00 
c00 
c8b 
c80 
c84 
c