INFO: task syz-executor0:9828 blocked for more than 120 seconds.
      Not tainted 4.4.105-ge303a83 #5
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor0   D ffff8801d61b77d8 28904  9828   3521 0x00000004
 ffff8801d61b77d8 dffffc0000000000 ffff8800b4232030 ffff8801d61b77b8
 ffffffff81229f2f ffff8800b4232000 ffff8801db51f838 ffff8801db51f860
 ffff8801db51ef58 ffff8801da655f00 ffff8800b42317c0 ffff8801d61b0000
Call Trace:
 [<ffffffff8373c3aa>] schedule+0x9a/0x1c0 kernel/sched/core.c:3351
 [<ffffffff8374665f>] rwsem_down_read_failed+0x1bf/0x300 kernel/locking/rwsem-xadd.c:250
 [<ffffffff81cfa3c4>] call_rwsem_down_read_failed+0x14/0x30 arch/x86/lib/rwsem.S:90
 [<ffffffff81f101ac>] n_tty_read+0x21c/0x1c30 drivers/tty/n_tty.c:2184
 [<ffffffff81efd8dc>] tty_read+0x13c/0x210 drivers/tty/tty_io.c:1071
 [<ffffffff814f759c>] do_loop_readv_writev+0x11c/0x1e0 fs/read_write.c:680
 [<ffffffff814f96f2>] do_readv_writev+0x552/0x660 fs/read_write.c:810
 [<ffffffff814f985a>] vfs_readv+0x5a/0xa0 fs/read_write.c:834
 [<ffffffff814fbd33>] SYSC_readv fs/read_write.c:860 [inline]
 [<ffffffff814fbd33>] SyS_readv+0xd3/0x260 fs/read_write.c:852
 [<ffffffff8374ab36>] entry_SYSCALL_64_fastpath+0x16/0x76
3 locks held by syz-executor0/9828:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff81f158ad>] tty_ldisc_ref_wait+0x1d/0xa0 drivers/tty/tty_ldisc.c:264
 #1:  (&ldata->atomic_read_lock){+.+.+.}, at: [<ffffffff81f1018d>] n_tty_read+0x1fd/0x1c30 drivers/tty/n_tty.c:2180
 #2:  (&o_tty->termios_rwsem/1){++++.+}, at: [<ffffffff81f101ac>] n_tty_read+0x21c/0x1c30 drivers/tty/n_tty.c:2184
Sending NMI to all CPUs:
NMI backtrace for cpu 0
CPU: 0 PID: 483 Comm: khungtaskd Not tainted 4.4.105-ge303a83 #5
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801d9edc740 task.stack: ffff8801da7b8000
RIP: 0010:[<ffffffff810c0777>]  [<ffffffff810c0777>] native_apic_mem_write arch/x86/include/asm/apic.h:94 [inline]
RIP: 0010:[<ffffffff810c0777>]  [<ffffffff810c0777>] __default_send_IPI_dest_field arch/x86/include/asm/ipi.h:119 [inline]
RIP: 0010:[<ffffffff810c0777>]  [<ffffffff810c0777>] _flat_send_IPI_mask arch/x86/kernel/apic/apic_flat_64.c:61 [inline]
RIP: 0010:[<ffffffff810c0777>]  [<ffffffff810c0777>] flat_send_IPI_mask+0xf7/0x1a0 arch/x86/kernel/apic/apic_flat_64.c:69
RSP: 0018:ffff8801da7bfcb8  EFLAGS: 00000046
RAX: 0000000003000000 RBX: 0000000000000c00 RCX: 0000000000000000
RDX: 0000000000000c00 RSI: 0000000000000000 RDI: ffffffffff5fb300
RBP: ffff8801da7bfce0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000246
R13: 0000000000000003 R14: ffffffff8426ace0 R15: 0000000000000002
FS:  0000000000000000(0000) GS:ffff8801db400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c422237000 CR3: 00000000b5db1000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff8426ace0 ffffffff847e73c0 ffffffff847e4964 0000000000000001
 dffffc0000000000 ffff8801da7bfd00 ffffffff810b62ab fffffbfff08fc92c
 0000000000019460 ffff8801da7bfd68 ffffffff81cd3e78 ffff8801da7bfd28
Call Trace:
 [<ffffffff810b62ab>] nmi_raise_cpu_backtrace+0x5b/0x70 arch/x86/kernel/apic/hw_nmi.c:33
 [<ffffffff81cd3e78>] nmi_trigger_all_cpu_backtrace+0x428/0x590 lib/nmi_backtrace.c:85
 [<ffffffff810b6344>] arch_trigger_all_cpu_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 [<ffffffff8134e976>] trigger_all_cpu_backtrace include/linux/nmi.h:44 [inline]
 [<ffffffff8134e976>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff8134e976>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff8134e976>] watchdog+0x636/0xa20 kernel/hung_task.c:238
 [<ffffffff81185b45>] kthread+0x245/0x310 kernel/kthread.c:211
 [<ffffffff8374aeef>] ret_from_fork+0x3f/0x70 arch/x86/entry/entry_64.S:468
Code: b3 5f ff f6 c4 10 75 e1 44 89 e8 c1 e0 18 89 04 25 10 b3 5f ff 44 89 fa 09 da 80 cf 04 41 83 ff 02 0f 44 d3 89 14 25 00 b3 5f ff <41> f7 c4 00 02 00 00 74 1a e8 8b 9d 16 00 4c 89 e7 57 9d 0f 1f 
NMI backtrace for cpu 1
CPU: 1 PID: 3158 Comm: rsyslogd Not tainted 4.4.105-ge303a83 #5
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8800b9524740 task.stack: ffff8801d4468000
RIP: 0010:[<ffffffff81223861>]  [<ffffffff81223861>] __lock_is_held+0x91/0xf0 kernel/locking/lockdep.c:3463
RSP: 0018:ffff8801d446fa78  EFLAGS: 00000086
RAX: 0000000000000000 RBX: ffff8800b9524740 RCX: 000000000000000a
RDX: 1ffff100172a49f5 RSI: ffffffff842b7700 RDI: ffffffff842b76c0
RBP: ffff8801d446faa8 R08: ffff8801d446fc10 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffed00172a49f5
R13: ffffffff842b76c0 R14: ffff8800b9524fb0 R15: 0000000000000000
FS:  00007f85771f8700(0000) GS:ffff8801db500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c422339000 CR3: 00000001d572b000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffff8800b9524fa8 0000000000000246 ffff8800b9524740 ffffffff842b76c0
 000000000000052c 0000000000000400 ffff8801d446fad0 ffffffff81224d00
 ffff8800b9524740 0000000000000000 ffffffff83fb0ed5 ffff8801d446fb08
Call Trace:
 [<ffffffff81224d00>] lock_is_held+0xb0/0x140 kernel/locking/lockdep.c:3630
 [<ffffffff81199a51>] ___might_sleep+0x361/0x460 kernel/sched/core.c:7938
 [<ffffffff81199be0>] __might_sleep+0x90/0x1a0 kernel/sched/core.c:7930
 [<ffffffff814d6c7c>] slab_pre_alloc_hook mm/slub.c:1324 [inline]
 [<ffffffff814d6c7c>] slab_alloc_node mm/slub.c:2527 [inline]
 [<ffffffff814d6c7c>] slab_alloc mm/slub.c:2609 [inline]
 [<ffffffff814d6c7c>] kmem_cache_alloc_trace+0x14c/0x2b0 mm/slub.c:2626
 [<ffffffff81259a5a>] kmalloc include/linux/slab.h:470 [inline]
 [<ffffffff81259a5a>] syslog_print kernel/printk/printk.c:1148 [inline]
 [<ffffffff81259a5a>] do_syslog+0x52a/0xb00 kernel/printk/printk.c:1331
 [<ffffffff81660d45>] kmsg_read+0x65/0x80 fs/proc/kmsg.c:39
 [<ffffffff81639ccc>] proc_reg_read+0xbc/0x180 fs/proc/inode.c:202
 [<ffffffff814f6d8a>] __vfs_read+0xda/0x3e0 fs/read_write.c:432
 [<ffffffff814f8a21>] vfs_read+0xe1/0x340 fs/read_write.c:454
 [<ffffffff814fb393>] SYSC_read fs/read_write.c:569 [inline]
 [<ffffffff814fb393>] SyS_read+0xd3/0x1c0 fs/read_write.c:562
 [<ffffffff8374ab36>] entry_SYSCALL_64_fastpath+0x16/0x76
Code: 00 00 fc ff df 49 c1 ec 03 49 01 c4 eb 1a 41 0f b6 04 24 41 83 c7 01 84 c0 74 04 3c 03 7e 53 44 39 bb 68 08 00 00 7e 2b 49 63 c7 <4c> 89 ee 48 8d 04 80 49 8d 3c c6 e8 ef f9 ff ff 85 c0 74 cf 48