INFO: task syz-executor6:21913 blocked for more than 120 seconds.
      Not tainted 4.9.108-gb7d377b #50
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor6   D24504 21913   3830 0x00000004
 ffff8801cf90e000 ffff8801bd9739c0 ffff8801d988cfc0 ffff8801cccb9800
 ffff8801db321c18 ffff88019820f890 ffffffff839e8aed 1ffff10033041f06
 ffffffff855802f0 0000000041b58ab3 00ffffff843c23b8 ffff8801db3224e8
Call Trace:
 [<ffffffff839ea0ef>] schedule+0x7f/0x1b0 kernel/sched/core.c:3557
 [<ffffffff839f6501>] schedule_timeout+0x861/0xf70 kernel/time/timer.c:1768
 [<ffffffff839e82ca>] io_schedule_timeout+0x1ba/0x390 kernel/sched/core.c:5180
 [<ffffffff839eb539>] io_schedule include/linux/sched.h:460 [inline]
 [<ffffffff839eb539>] bit_wait_io+0x19/0xa0 kernel/sched/wait.c:582
 [<ffffffff839eadde>] __wait_on_bit_lock+0xce/0x1c0 kernel/sched/wait.c:421
 [<ffffffff8143451f>] __lock_page+0xff/0x160 mm/filemap.c:934
 [<ffffffff8143a2e9>] lock_page include/linux/pagemap.h:454 [inline]
 [<ffffffff8143a2e9>] pagecache_get_page+0x409/0x720 mm/filemap.c:1216
 [<ffffffff8146bbe6>] find_lock_page include/linux/pagemap.h:284 [inline]
 [<ffffffff8146bbe6>] truncate_inode_pages_range+0xca6/0x1290 mm/truncate.c:320
 [<ffffffff8163288d>] blkdev_fallocate+0x21d/0x440 fs/block_dev.c:1817
 [<ffffffff815686b9>] vfs_fallocate+0x359/0x600 fs/open.c:329
 [<ffffffff8156b5c3>] SYSC_fallocate fs/open.c:352 [inline]
 [<ffffffff8156b5c3>] SyS_fallocate+0x53/0x90 fs/open.c:346
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839f99d3>] 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/3777:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff839f7b92>] 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
1 lock held by syz-executor6/21913:
 #0:  (sb_writers){.+.+.+}, at: [<ffffffff8156865b>] sb_start_write include/linux/fs.h:1573 [inline]
 #0:  (sb_writers){.+.+.+}, at: [<ffffffff8156865b>] vfs_fallocate+0x2fb/0x600 fs/open.c:328
1 lock held by syz-executor6/21943:
 #0:  (sb_writers){.+.+.+}, at: [<ffffffff8156865b>] sb_start_write include/linux/fs.h:1573 [inline]
 #0:  (sb_writers){.+.+.+}, at: [<ffffffff8156865b>] vfs_fallocate+0x2fb/0x600 fs/open.c:328

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

NMI backtrace for cpu 1
CPU: 1 PID: 519 Comm: khungtaskd Not tainted 4.9.108-gb7d377b #50
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d863fd08 ffffffff81eb3e29 0000000000000000 0000000000000001
 0000000000000001 0000000000000001 ffffffff810b96a0 ffff8801d863fd40
 ffffffff81ebf127 0000000000000001 0000000000000000 0000000000000003
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
 [<ffffffff810b97a4>] 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
 [<ffffffff839f9b9c>] 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
CPU: 0 PID: 25 Comm: kworker/0:1 Not tainted 4.9.108-gb7d377b #50
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events_power_efficient gc_worker
c
task: ffff8801d9408000 task.stack: ffff8801d9410000
RIP: 0010:[<ffffffff812355fb>] 
c [<ffffffff812355fb>] mark_held_locks+0xcb/0x130 kernel/locking/lockdep.c:2660
RSP: 0018:ffff8801d9417b50  EFLAGS: 00000002
RAX: 0000000000000001 RBX: 0000000000000001 RCX: 1ffff1003b281122
RDX: 1ffffffff0abb11a RSI: ffff8801d94088f0 RDI: ffffffff855d88d0
RBP: ffff8801d9417b90 R08: ffff8801d9408910 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801d94088c8
R13: ffffed003b281118 R14: ffff8801d9408000 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9e8df21000 CR3: 00000001b8c01000 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 0000000000000046
c ffff8801d94088c0
c 0000000200000003
c ffff8801d9408000
c
 ffffffff831f2e03
c ffffffff84c657e0
c ffffffff84c657e8
c 0000000000000000
c
 ffff8801d9417bb0
c ffffffff812358c6
c 0000000000000293
c dffffc0000000000
c
Call Trace:
 [<ffffffff812358c6>] __trace_hardirqs_on_caller kernel/locking/lockdep.c:2681 [inline]
 [<ffffffff812358c6>] trace_hardirqs_on_caller+0x266/0x590 kernel/locking/lockdep.c:2736
 [<ffffffff81235bfd>] trace_hardirqs_on+0xd/0x10 kernel/locking/lockdep.c:2743
 [<ffffffff831f2e03>] seqcount_lockdep_reader_access include/linux/seqlock.h:82 [inline]
 [<ffffffff831f2e03>] read_seqcount_begin include/linux/seqlock.h:163 [inline]
 [<ffffffff831f2e03>] nf_conntrack_get_ht include/net/netfilter/nf_conntrack.h:325 [inline]
 [<ffffffff831f2e03>] gc_worker+0x193/0x620 net/netfilter/nf_conntrack_core.c:968
 [<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
 [<ffffffff839f9b9c>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373
Code: 
c07 
c42 
c0f 
cb6 
c04 
c38 
c38 
cd0 
c7f 
c04 
c84 
cc0 
c75 
c5e 
c0f 
cb6 
c46 
c22 
c8b 
c55 
cd4 
ca8 
c03 
c0f 
c45 
c55 
cd0 
ca8 
c04 
c74 
c0c 
c4c 
c89 
cf7 
ce8 
cb9 
cec 
cff 
cff 
c85 
cc0 
c74 
c1e 
c<41> 
c0f 
cb6 
c45 
c00 
c83 
cc3 
c01 
c84 
cc0 
c74 
c04 
c3c 
c03 
c7e 
c40 
c41 
c39 
c9e 
cc0 
c08 
c