INFO: task syz-executor0:29654 blocked for more than 120 seconds.
      Not tainted 4.9.108-gb7d377b #47
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor0   D29160 29654  25955 0x00000004
 ffff880194d33000 ffff8801c7d024c0 ffff8801c7d024c0 ffff880190b58000
 ffff8801db321c18 ffff880188b67728 ffffffff839e8aed ffffffff812355f7
 0000000000000000 ffff880194d338c0 0000000600000007 ffff8801db3224e8
Call Trace:
 [<ffffffff839ea0ef>] schedule+0x7f/0x1b0 kernel/sched/core.c:3557
 [<ffffffff839f5728>] __rwsem_down_write_failed_common kernel/locking/rwsem-xadd.c:526 [inline]
 [<ffffffff839f5728>] 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
 [<ffffffff839f34fc>] __down_write arch/x86/include/asm/rwsem.h:125 [inline]
 [<ffffffff839f34fc>] down_write+0x5c/0xa0 kernel/locking/rwsem.c:54
 [<ffffffff8156a6e8>] inode_lock include/linux/fs.h:766 [inline]
 [<ffffffff8156a6e8>] do_truncate2+0x128/0x1f0 fs/open.c:61
 [<ffffffff815a62ee>] handle_truncate fs/namei.c:2990 [inline]
 [<ffffffff815a62ee>] do_last fs/namei.c:3419 [inline]
 [<ffffffff815a62ee>] path_openat+0x251e/0x3590 fs/namei.c:3534
 [<ffffffff815ab627>] do_filp_open+0x197/0x270 fs/namei.c:3568
 [<ffffffff8156ddfd>] do_sys_open+0x30d/0x5c0 fs/open.c:1072
 [<ffffffff8156e157>] SYSC_open fs/open.c:1090 [inline]
 [<ffffffff8156e157>] SyS_open fs/open.c:1085 [inline]
 [<ffffffff8156e157>] SYSC_creat fs/open.c:1110 [inline]
 [<ffffffff8156e157>] SyS_creat+0x27/0x30 fs/open.c:1108
 [<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/3775:
 #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
2 locks held by syz-executor0/29654:
 #0:  (sb_writers#14){.+.+.+}, at: [<ffffffff815e08df>] sb_start_write include/linux/fs.h:1573 [inline]
 #0:  (sb_writers#14){.+.+.+}, at: [<ffffffff815e08df>] mnt_want_write+0x3f/0xb0 fs/namespace.c:391
 #1:  (&sb->s_type->i_mutex_key#17){++++++}, at: [<ffffffff8156a6e8>] inode_lock include/linux/fs.h:766 [inline]
 #1:  (&sb->s_type->i_mutex_key#17){++++++}, at: [<ffffffff8156a6e8>] do_truncate2+0x128/0x1f0 fs/open.c:61

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

NMI backtrace for cpu 0
CPU: 0 PID: 519 Comm: khungtaskd Not tainted 4.9.108-gb7d377b #47
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d8477d08 ffffffff81eb3e29 0000000000000000 0000000000000000
 0000000000000000 0000000000000001 ffffffff810b96a0 ffff8801d8477d40
 ffffffff81ebf127 0000000000000000 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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 29618 Comm: syz-executor0 Not tainted 4.9.108-gb7d377b #47
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff880190b58000 task.stack: ffff8801b4948000
RIP: 0010:[<ffffffff812cb9b1>] 
c [<ffffffff812cb9b1>] tick_program_event+0x1/0x190 kernel/time/tick-oneshot.c:28
RSP: 0018:ffff8801db307f20  EFLAGS: 00000046
RAX: 0000000080010000 RBX: ffff8801db31c900 RCX: 0000000000000000
RDX: 0000000000010001 RSI: 0000000000000000 RDI: 000000e482cd5b1d
RBP: ffff8801db307fa0 R08: 0000000000000092 R09: 0000000000000001
R10: 0000000000000000 R11: 1ffff1003216b12c R12: ffffed003b66392f
R13: ffff8801db31c976 R14: 000000e482cd5b1d R15: dffffc0000000000
FS:  00007fc6cb10f700(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc60e33b000 CR3: 00000001b615e000 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffff8801db307fa0
c ffffffff812a5bb1
c ffff8801db31c978
c 000000e482cd4333
c
 00000003db307f80
c ffff8801db31c970
c ffff8801db31caa8
c ffff8801db31ca68
c
 ffff8801db31ca28
c 7fffffffffffffff
c 1ffff1003b66392e
c ffff8801db3180c0
c
Call Trace:
 [<ffffffff810b1e54>] local_apic_timer_interrupt+0x74/0xa0 arch/x86/kernel/apic/apic.c:935
 [<ffffffff839ff19c>] smp_apic_timer_interrupt+0x7c/0xa0 arch/x86/kernel/apic/apic.c:959
 [<ffffffff839fb330>] apic_timer_interrupt+0xa0/0xb0 arch/x86/entry/entry_64.S:648
 <EOI> 
d [<ffffffff81230a4f>] ? arch_local_irq_restore arch/x86/include/asm/paravirt.h:768 [inline]
 <EOI> 
d [<ffffffff81230a4f>] ? lock_is_held+0xff/0x140 kernel/locking/lockdep.c:3796
 [<ffffffff811bb4f7>] ___might_sleep+0x1c7/0x260 kernel/sched/core.c:7958
 [<ffffffff811bb625>] __might_sleep+0x95/0x1a0 kernel/sched/core.c:7949
 [<ffffffff8143a29d>] lock_page include/linux/pagemap.h:452 [inline]
 [<ffffffff8143a29d>] pagecache_get_page+0x3bd/0x720 mm/filemap.c:1216
 [<ffffffff816252a9>] find_or_create_page include/linux/pagemap.h:309 [inline]
 [<ffffffff816252a9>] grow_dev_page fs/buffer.c:1005 [inline]
 [<ffffffff816252a9>] grow_buffers fs/buffer.c:1078 [inline]
 [<ffffffff816252a9>] __getblk_slow fs/buffer.c:1105 [inline]
 [<ffffffff816252a9>] __getblk_gfp+0x249/0x710 fs/buffer.c:1386
 [<ffffffff81628b8d>] __bread_gfp+0x2d/0x270 fs/buffer.c:1420
 [<ffffffff818c46b0>] sb_bread include/linux/buffer_head.h:300 [inline]
 [<ffffffff818c46b0>] fat_ent_bread+0x160/0x2f0 fs/fat/fatent.c:106
 [<ffffffff818c63ab>] fat_ent_read_block fs/fat/fatent.c:441 [inline]
 [<ffffffff818c63ab>] fat_alloc_clusters+0x51b/0xe10 fs/fat/fatent.c:489
 [<ffffffff818d357f>] fat_add_cluster+0x6f/0xe0 fs/fat/inode.c:100
 [<ffffffff818c7d0c>] fat_fallocate+0x23c/0x2d0 fs/fat/file.c:262
 [<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
Code: 
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c