INFO: task syz-executor0:5047 blocked for more than 140 seconds.
      Not tainted 4.9.128+ #46
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor0   D26152  5047   2086 0x20020004
 ffff8801c4e7c740 0000000000000000 ffff8801d1124d00 ffff8801da6b2f80
 ffff8801db721018 ffff8801c6597080 ffffffff827e7bc2 0000000000000292
 0000000000000002 0000000041b58ab3 00ffffff82e28d6a ffff8801db7218f0
Call Trace:
 [<ffffffff827e90ef>] schedule+0x7f/0x1b0 kernel/sched/core.c:3553
 [<ffffffff815a1369>] wb_wait_for_completion+0x149/0x1b0 fs/fs-writeback.c:221
 [<ffffffff815a15d7>] __writeback_inodes_sb_nr+0x207/0x300 fs/fs-writeback.c:2310
 [<ffffffff815a177a>] try_to_writeback_inodes_sb_nr+0x4a/0x70 fs/fs-writeback.c:2361
 [<ffffffff815a17c5>] try_to_writeback_inodes_sb+0x25/0x30 fs/fs-writeback.c:2377
 [<ffffffff816c0e08>] ext4_nonda_switch+0x188/0x1c0 fs/ext4/inode.c:2884
 [<ffffffff816dc544>] ext4_da_write_begin+0x104/0x1020 fs/ext4/inode.c:2922
 [<ffffffff8140f1aa>] generic_perform_write+0x28a/0x500 mm/filemap.c:2753
 [<ffffffff814120f2>] __generic_file_write_iter+0x352/0x540 mm/filemap.c:2878
 [<ffffffff816b2d4d>] ext4_file_write_iter+0x63d/0xd70 fs/ext4/file.c:165
 [<ffffffff81506e27>] vfs_iter_write+0x2d7/0x450 fs/read_write.c:390
 [<ffffffff815ae09b>] iter_file_splice_write+0x5fb/0xb30 fs/splice.c:768
 [<ffffffff815a9658>] do_splice_from fs/splice.c:870 [inline]
 [<ffffffff815a9658>] direct_splice_actor+0x128/0x190 fs/splice.c:1037
 [<ffffffff815ab261>] splice_direct_to_actor+0x2c1/0x7e0 fs/splice.c:992
 [<ffffffff815ab923>] do_splice_direct+0x1a3/0x270 fs/splice.c:1080
 [<ffffffff8150d3e0>] do_sendfile+0x4f0/0xc30 fs/read_write.c:1393
 [<ffffffff8150f5b1>] C_SYSC_sendfile fs/read_write.c:1469 [inline]
 [<ffffffff8150f5b1>] compat_SyS_sendfile+0xd1/0x160 fs/read_write.c:1458
 [<ffffffff81006311>] do_syscall_32_irqs_on arch/x86/entry/common.c:328 [inline]
 [<ffffffff81006311>] do_fast_syscall_32+0x2f1/0xa10 arch/x86/entry/common.c:390
 [<ffffffff827f93a0>] entry_SYSENTER_compat+0x90/0xa2 arch/x86/entry/entry_64_compat.S:137

Showing all locks held in the system:
2 locks held by khungtaskd/24:
 #0:  (rcu_read_lock){......}, at: [<ffffffff8131b80c>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff8131b80c>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff813fded4>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
1 lock held by rsyslogd/1896:
 #0:  (&f->f_pos_lock){+.+.+.}, at: [<ffffffff8156c8dc>] __fdget_pos+0xac/0xd0 fs/file.c:781
2 locks held by getty/2024:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff827f5f12>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+.+.}, at: [<ffffffff81d1fc82>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142
3 locks held by kworker/u4:4/2228:
 #0:  ("writeback"){.+.+.+}, at: [<ffffffff81130abc>] process_one_work+0x73c/0x1530 kernel/workqueue.c:2085
 #1:  ((&(&wb->dwork)->work)){+.+.+.}, at: [<ffffffff81130af4>] process_one_work+0x774/0x1530 kernel/workqueue.c:2089
 #2:  (&sbi->s_journal_flag_rwsem){.+.+.+}, at: [<ffffffff8143384f>] do_writepages+0xef/0x1d0 mm/page-writeback.c:2331
1 lock held by syz-executor0/5044:
 #0:  (&sbi->s_journal_flag_rwsem){.+.+.+}, at: [<ffffffff8143384f>] do_writepages+0xef/0x1d0 mm/page-writeback.c:2331
3 locks held by syz-executor0/5047:
 #0:  (sb_writers#4){.+.+.+}, at: [<ffffffff8150d970>] file_start_write include/linux/fs.h:2640 [inline]
 #0:  (sb_writers#4){.+.+.+}, at: [<ffffffff8150d970>] do_sendfile+0xa80/0xc30 fs/read_write.c:1392
 #1:  (&sb->s_type->i_mutex_key#10){++++++}, at: [<ffffffff816b2832>] inode_lock include/linux/fs.h:766 [inline]
 #1:  (&sb->s_type->i_mutex_key#10){++++++}, at: [<ffffffff816b2832>] ext4_file_write_iter+0x122/0xd70 fs/ext4/file.c:100
 #2:  (&type->s_umount_key#32){++++++}, at: [<ffffffff815a1759>] try_to_writeback_inodes_sb_nr+0x29/0x70 fs/fs-writeback.c:2358
2 locks held by syz-executor0/5069:
 #0:  (sb_writers#4){.+.+.+}, at: [<ffffffff8157524f>] sb_start_write include/linux/fs.h:1573 [inline]
 #0:  (sb_writers#4){.+.+.+}, at: [<ffffffff8157524f>] mnt_want_write+0x3f/0xb0 fs/namespace.c:391
 #1:  (&sb->s_type->i_mutex_key#10){++++++}, at: [<ffffffff81502fd8>] inode_lock include/linux/fs.h:766 [inline]
 #1:  (&sb->s_type->i_mutex_key#10){++++++}, at: [<ffffffff81502fd8>] do_truncate2+0x128/0x1f0 fs/open.c:61
2 locks held by syz-executor0/5106:
 #0:  (sb_writers#4){.+.+.+}, at: [<ffffffff81503a66>] sb_start_write include/linux/fs.h:1573 [inline]
 #0:  (sb_writers#4){.+.+.+}, at: [<ffffffff81503a66>] do_sys_ftruncate.constprop.5+0x206/0x470 fs/open.c:208
 #1:  (&sb->s_type->i_mutex_key#10){++++++}, at: [<ffffffff81502fd8>] inode_lock include/linux/fs.h:766 [inline]
 #1:  (&sb->s_type->i_mutex_key#10){++++++}, at: [<ffffffff81502fd8>] do_truncate2+0x128/0x1f0 fs/open.c:61
2 locks held by syz-executor0/5107:
 #0:  (sb_writers#4){.+.+.+}, at: [<ffffffff8150d970>] file_start_write include/linux/fs.h:2640 [inline]
 #0:  (sb_writers#4){.+.+.+}, at: [<ffffffff8150d970>] do_sendfile+0xa80/0xc30 fs/read_write.c:1392
 #1:  (&sb->s_type->i_mutex_key#10){++++++}, at: [<ffffffff816b2832>] inode_lock include/linux/fs.h:766 [inline]
 #1:  (&sb->s_type->i_mutex_key#10){++++++}, at: [<ffffffff816b2832>] ext4_file_write_iter+0x122/0xd70 fs/ext4/file.c:100
2 locks held by syz-executor0/5109:
 #0:  (sb_writers#4){.+.+.+}, at: [<ffffffff8157524f>] sb_start_write include/linux/fs.h:1573 [inline]
 #0:  (sb_writers#4){.+.+.+}, at: [<ffffffff8157524f>] mnt_want_write+0x3f/0xb0 fs/namespace.c:391
 #1:  (&sb->s_type->i_mutex_key#10){++++++}, at: [<ffffffff81502fd8>] inode_lock include/linux/fs.h:766 [inline]
 #1:  (&sb->s_type->i_mutex_key#10){++++++}, at: [<ffffffff81502fd8>] do_truncate2+0x128/0x1f0 fs/open.c:61

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

NMI backtrace for cpu 1
CPU: 1 PID: 24 Comm: khungtaskd Not tainted 4.9.128+ #46
 ffff8801d9907d08 ffffffff81b2b9e9 0000000000000000 0000000000000001
 0000000000000001 0000000000000001 ffffffff81098180 ffff8801d9907d40
 ffffffff81b36af9 0000000000000001 0000000000000000 0000000000000003
Call Trace:
 [<ffffffff81b2b9e9>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81b2b9e9>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81b36af9>] nmi_cpu_backtrace.cold.0+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81b36a8c>] nmi_trigger_cpumask_backtrace+0x12c/0x151 lib/nmi_backtrace.c:60
 [<ffffffff81098284>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff8131bd9d>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff8131bd9d>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff8131bd9d>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff8131bd9d>] watchdog+0x6ad/0xa20 kernel/hung_task.c:239
 [<ffffffff8114272d>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff827f801c>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0 skipped: idling at pc 0xffffffff827f6a56