b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=2, b_blocknr=16
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
INFO: task syz-executor0:10099 blocked for more than 120 seconds.
      Not tainted 4.9.105-gd7e64f8 #40
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor0   D29160 10099   3885 0x00000004
 ffff880185466000
__find_get_block_slow() failed. block=2, b_blocknr=16
 ffff88018ac03480 ffff8801d81d6a00 ffff880190e44800
 0000000000000000 ffff8801854668c0 0000000600000007 ffff8801db2224e8
Call Trace:
b_state=0x00000029, b_size=512
 [<ffffffff839ea21f>] schedule+0x7f/0x1b0 kernel/sched/core.c:3557
device loop0 blocksize: 4096
 [<ffffffff839f5858>] __rwsem_down_write_failed_common kernel/locking/rwsem-xadd.c:526 [inline]
 [<ffffffff839f5858>] rwsem_down_write_failed+0x598/0x990 kernel/locking/rwsem-xadd.c:555
 [<ffffffff81ee8487>] call_rwsem_down_write_failed+0x17/0x30 arch/x86/lib/rwsem.S:105
__find_get_block_slow() failed. block=2, b_blocknr=16
 [<ffffffff839f362c>] __down_write arch/x86/include/asm/rwsem.h:125 [inline]
 [<ffffffff839f362c>] down_write+0x5c/0xa0 kernel/locking/rwsem.c:54
b_state=0x00000029, b_size=512
 [<ffffffff8156aaa8>] inode_lock include/linux/fs.h:766 [inline]
 [<ffffffff8156aaa8>] do_truncate2+0x128/0x1f0 fs/open.c:61
device loop0 blocksize: 4096
 [<ffffffff815a66ae>] handle_truncate fs/namei.c:2990 [inline]
 [<ffffffff815a66ae>] do_last fs/namei.c:3419 [inline]
 [<ffffffff815a66ae>] path_openat+0x251e/0x3590 fs/namei.c:3534
 [<ffffffff815ab9e7>] do_filp_open+0x197/0x270 fs/namei.c:3568
__find_get_block_slow() failed. block=2, b_blocknr=16
b_state=0x00000029, b_size=512
 [<ffffffff8156e1bd>] do_sys_open+0x30d/0x5c0 fs/open.c:1072
device loop0 blocksize: 4096
 [<ffffffff8156e517>] SYSC_open fs/open.c:1090 [inline]
 [<ffffffff8156e517>] SyS_open fs/open.c:1085 [inline]
 [<ffffffff8156e517>] SYSC_creat fs/open.c:1110 [inline]
 [<ffffffff8156e517>] SyS_creat+0x27/0x30 fs/open.c:1108
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839f9b13>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
__find_get_block_slow() failed. block=2, b_blocknr=16

Showing all locks held in the system:
2 locks held by khungtaskd/519:
b_state=0x00000029, b_size=512
 #0: 
device loop0 blocksize: 4096
 (rcu_read_lock){......}, at: [<ffffffff81366b9c>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 (rcu_read_lock){......}, at: [<ffffffff81366b9c>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
1 lock held by rsyslogd/3677:
__find_get_block_slow() failed. block=2, b_blocknr=16
 #0:  (&f->f_pos_lock){+.+.+.}, at: [<ffffffff815d83fc>] __fdget_pos+0xac/0xd0 fs/file.c:781
2 locks held by getty/3772:
b_state=0x00000029, b_size=512
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff839f7cc2>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
device loop0 blocksize: 4096
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff82120062>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2133
2 locks held by syz-executor0/10099:
 #0:  (sb_writers#11){.+.+.+}, at: [<ffffffff815e0c9f>] sb_start_write include/linux/fs.h:1573 [inline]
 #0:  (sb_writers#11){.+.+.+}, at: [<ffffffff815e0c9f>] mnt_want_write+0x3f/0xb0 fs/namespace.c:391
 #1:  (&sb->s_type->i_mutex_key#14){++++++}, at: [<ffffffff8156aaa8>] inode_lock include/linux/fs.h:766 [inline]
 #1:  (&sb->s_type->i_mutex_key#14){++++++}, at: [<ffffffff8156aaa8>] do_truncate2+0x128/0x1f0 fs/open.c:61
__find_get_block_slow() failed. block=2, b_blocknr=16
2 locks held by syz-executor0/10101:
 #0:  (sb_writers#11){.+.+.+}
b_state=0x00000029, b_size=512
, at: [<ffffffff815e0c9f>] sb_start_write include/linux/fs.h:1573 [inline]
, at: [<ffffffff815e0c9f>] mnt_want_write+0x3f/0xb0 fs/namespace.c:391
2 locks held by syz-executor0/10104:
 #0: 
device loop0 blocksize: 4096
 (sb_writers#11){.+.+.+}, at: [<ffffffff81568a1b>] sb_start_write include/linux/fs.h:1573 [inline]
 (sb_writers#11){.+.+.+}, at: [<ffffffff81568a1b>] vfs_fallocate+0x2fb/0x600 fs/open.c:328
2 locks held by syz-executor0/10107:
 #0:  (sb_writers#11){.+.+.+}, at: [<ffffffff815e0c9f>] sb_start_write include/linux/fs.h:1573 [inline]
 #0:  (sb_writers#11){.+.+.+}, at: [<ffffffff815e0c9f>] mnt_want_write+0x3f/0xb0 fs/namespace.c:391
 #1:  (&sb->s_type->i_mutex_key#14){++++++}, at: [<ffffffff8156aaa8>] inode_lock include/linux/fs.h:766 [inline]
 #1:  (&sb->s_type->i_mutex_key#14){++++++}, at: [<ffffffff8156aaa8>] do_truncate2+0x128/0x1f0 fs/open.c:61
1 lock held by init/10113:
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff8211a10c>] tty_open_by_driver drivers/tty/tty_io.c:2047 [inline]
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff8211a10c>] tty_open+0x46c/0xe20 drivers/tty/tty_io.c:2125
__find_get_block_slow() failed. block=2, b_blocknr=16
1 lock held by init/10114:
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff8211a10c>] tty_open_by_driver drivers/tty/tty_io.c:2047 [inline]
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff8211a10c>] tty_open+0x46c/0xe20 drivers/tty/tty_io.c:2125
b_state=0x00000029, b_size=512
1 lock held by init/10115:
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff8211a10c>] tty_open_by_driver drivers/tty/tty_io.c:2047 [inline]
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff8211a10c>] tty_open+0x46c/0xe20 drivers/tty/tty_io.c:2125
device loop0 blocksize: 4096
1 lock held by init/10116:
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff8211a10c>] tty_open_by_driver drivers/tty/tty_io.c:2047 [inline]
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff8211a10c>] tty_open+0x46c/0xe20 drivers/tty/tty_io.c:2125
1 lock held by init/10117:
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff8211a10c>] tty_open_by_driver drivers/tty/tty_io.c:2047 [inline]
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff8211a10c>] tty_open+0x46c/0xe20 drivers/tty/tty_io.c:2125

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

NMI backtrace for cpu 0
CPU: 0 PID: 519 Comm: khungtaskd Not tainted 4.9.105-gd7e64f8 #40
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d85d7d08 ffffffff81eb41a9 0000000000000000 0000000000000000
 0000000000000000 0000000000000001 ffffffff810b96a0 ffff8801d85d7d40
 ffffffff81ebf4a7 0000000000000000 0000000000000000 0000000000000003
__find_get_block_slow() failed. block=2, b_blocknr=16
Call Trace:
 [<ffffffff81eb41a9>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81eb41a9>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
 [<ffffffff81ebf4a7>] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99
__find_get_block_slow() failed. block=2, b_blocknr=16
 [<ffffffff81ebf43a>] 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
b_state=0x00000029, b_size=512
 [<ffffffff81367134>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81367134>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81367134>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81367134>] watchdog+0x6b4/0xa20 kernel/hung_task.c:239
device loop0 blocksize: 4096
 [<ffffffff8119d04d>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff839f9cdc>] 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: 10037 Comm: syz-executor0 Not tainted 4.9.105-gd7e64f8 #40
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801d787c800 task.stack: ffff8801d6c60000
RIP: 0010:[<ffffffff810c2bfc>] 
c [<ffffffff810c2bfc>] native_apic_mem_write+0xc/0x10 arch/x86/include/asm/apic.h:98
RSP: 0018:ffff8801db307dc8  EFLAGS: 00000046
RAX: ffffffff810c2bf0 RBX: ffffffff84432860 RCX: 0000000000000020
RDX: 1ffffffff0886529 RSI: 00000000000000d2 RDI: 0000000000000380
RBP: ffff8801db307dc8 R08: ffff88021fffd058 R09: 0000000000000004
R10: ffffed0043fffa09 R11: 0000000000000001 R12: 00000000000000d2
R13: 1ffff1003b660fc0 R14: 0000000000000003 R15: ffff8801db307e60
FS:  00007f34666bb700(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f96ccd5c4c0 CR3: 00000001c1fed000 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffff8801db307de8
c ffffffff810b13c0
c 0000000000000003
c ffff8801db3180c0
c
 ffff8801db307e88
c ffffffff812c72d4
c 00000000db307eb0
c 0000000041b58ab3
c
 ffffffff843bdbe2
c ffffffff812c7020
c ffff8801db31c960
c 00000038bc8b6bd4
c
Call Trace:
 <IRQ> 
d [<ffffffff810b13c0>] apic_write arch/x86/include/asm/apic.h:398 [inline]
 <IRQ> 
d [<ffffffff810b13c0>] lapic_next_event+0x60/0x90 arch/x86/kernel/apic/apic.c:468
 [<ffffffff812c72d4>] clockevents_program_event+0x2b4/0x3e0 kernel/time/clockevents.c:339
 [<ffffffff812cbff4>] tick_program_event+0x104/0x190 kernel/time/tick-oneshot.c:47
 [<ffffffff812a60f1>] hrtimer_interrupt+0x1e1/0x430 kernel/time/hrtimer.c:1366
 [<ffffffff810b1e54>] local_apic_timer_interrupt+0x74/0xa0 arch/x86/kernel/apic/apic.c:935
 [<ffffffff839ff2dc>] smp_apic_timer_interrupt+0x7c/0xa0 arch/x86/kernel/apic/apic.c:959
 [<ffffffff839fb470>] apic_timer_interrupt+0xa0/0xb0 arch/x86/entry/entry_64.S:648
 <EOI> 
d [<ffffffff816246ea>] ? arch_local_irq_enable arch/x86/include/asm/paravirt.h:778 [inline]
 <EOI> 
d [<ffffffff816246ea>] ? lookup_bh_lru fs/buffer.c:1344 [inline]
 <EOI> 
d [<ffffffff816246ea>] ? __find_get_block+0x18a/0x4c0 fs/buffer.c:1356
 [<ffffffff816255a9>] __getblk_slow fs/buffer.c:1101 [inline]
 [<ffffffff816255a9>] __getblk_gfp+0x189/0x710 fs/buffer.c:1386
 [<ffffffff81628f4d>] __bread_gfp+0x2d/0x270 fs/buffer.c:1420
 [<ffffffff818c4a70>] sb_bread include/linux/buffer_head.h:300 [inline]
 [<ffffffff818c4a70>] fat_ent_bread+0x160/0x2f0 fs/fat/fatent.c:106
 [<ffffffff818c676b>] fat_ent_read_block fs/fat/fatent.c:441 [inline]
 [<ffffffff818c676b>] fat_alloc_clusters+0x51b/0xe10 fs/fat/fatent.c:489
 [<ffffffff818d393f>] fat_add_cluster+0x6f/0xe0 fs/fat/inode.c:100
 [<ffffffff818c80cc>] fat_fallocate+0x23c/0x2d0 fs/fat/file.c:262
 [<ffffffff81568a79>] vfs_fallocate+0x359/0x600 fs/open.c:329
 [<ffffffff8156b983>] SYSC_fallocate fs/open.c:352 [inline]
 [<ffffffff8156b983>] SyS_fallocate+0x53/0x90 fs/open.c:346
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839f9b13>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Code: 
c00 
c0f 
c1f 
c40 
c00 
c66 
c2e 
c0f 
c1f 
c84 
c00 
c00 
c00 
c00 
c00 
c55 
cbe 
c01 
c00 
c00 
c00 
c48 
c89 
ce5 
ce8 
ce2 
c2b 
c1b 
c00 
c5d 
cc3 
c55 
c89 
cff 
c48 
c89 
ce5 
c89 
cb7 
c00 
cc0 
c5f 
cff 
c<5d> 
cc3 
c66 
c90 
c48 
cb8 
c00 
c00 
c00 
c00 
c00 
cfc 
cff 
cdf 
c55 
c48 
c89 
ce5 
c53 
c89 
cfb 
c
__find_get_block_slow() failed. block=2, b_blocknr=16
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=2, b_blocknr=16
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096