b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
INFO: task syz-executor0:21426 blocked for more than 140 seconds.
__find_get_block_slow() failed. block=1, b_blocknr=8
      Not tainted 4.9.112-g9e79039 #7
b_state=0x00000029, b_size=512
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
device loop0 blocksize: 4096
syz-executor0   D
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
29384 21426  16487 0x00000004
b_state=0x00000029, b_size=512
 ffff8801cced6000
device loop0 blocksize: 4096
 ffff8801c2665500 ffff8801a0824000__find_get_block_slow() failed. block=1, b_blocknr=8
 ffff8801b7be0000b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
 ffff8801db321c18 ffff8801d89c7728
__find_get_block_slow() failed. block=1, b_blocknr=8
 ffffffff839e907db_state=0x00000029, b_size=512
 ffffffff81235667device loop0 blocksize: 4096
 0000000000000000 ffff8801cced68c0
__find_get_block_slow() failed. block=1, b_blocknr=8
 0000000600000007b_state=0x00000029, b_size=512
 ffff8801db3224e8device loop0 blocksize: 4096
Call Trace:
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
 [<ffffffff839ea67f>] schedule+0x7f/0x1b0 kernel/sched/core.c:3557
__find_get_block_slow() failed. block=1, b_blocknr=8
 [<ffffffff839f5cb8>] __rwsem_down_write_failed_common kernel/locking/rwsem-xadd.c:526 [inline]
 [<ffffffff839f5cb8>] rwsem_down_write_failed+0x598/0x990 kernel/locking/rwsem-xadd.c:555
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
 [<ffffffff81ee7527>] call_rwsem_down_write_failed+0x17/0x30 arch/x86/lib/rwsem.S:105
 [<ffffffff839f3a8c>] __down_write arch/x86/include/asm/rwsem.h:125 [inline]
 [<ffffffff839f3a8c>] down_write+0x5c/0xa0 kernel/locking/rwsem.c:54
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
 [<ffffffff8156a838>] inode_lock include/linux/fs.h:766 [inline]
 [<ffffffff8156a838>] do_truncate2+0x128/0x1f0 fs/open.c:61
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
 [<ffffffff815a643e>] handle_truncate fs/namei.c:2990 [inline]
 [<ffffffff815a643e>] do_last fs/namei.c:3419 [inline]
 [<ffffffff815a643e>] path_openat+0x251e/0x3590 fs/namei.c:3534
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
 [<ffffffff815ab777>] do_filp_open+0x197/0x270 fs/namei.c:3568
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
 [<ffffffff8156df4d>] do_sys_open+0x30d/0x5c0 fs/open.c:1072
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
 [<ffffffff8156e2a7>] SYSC_open fs/open.c:1090 [inline]
 [<ffffffff8156e2a7>] SyS_open fs/open.c:1085 [inline]
 [<ffffffff8156e2a7>] SYSC_creat fs/open.c:1110 [inline]
 [<ffffffff8156e2a7>] SyS_creat+0x27/0x30 fs/open.c:1108
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
__find_get_block_slow() failed. block=1, b_blocknr=8
 [<ffffffff839f9f53>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
b_state=0x00000029, b_size=512

Showing all locks held in the system:
device loop0 blocksize: 4096
2 locks held by khungtaskd/519:
__find_get_block_slow() failed. block=1, b_blocknr=8
 #0: 
b_state=0x00000029, b_size=512
 (device loop0 blocksize: 4096
rcu_read_lock){......}, at: [<ffffffff8136675c>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
rcu_read_lock){......}, at: [<ffffffff8136675c>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1: 
b_state=0x00000029, b_size=512
 (device loop0 blocksize: 4096
tasklist_lock){.+.+..}, at: [<ffffffff81425de7>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
1 lock held by rsyslogd/3683:
 #0: 
__find_get_block_slow() failed. block=1, b_blocknr=8
 (b_state=0x00000029, b_size=512
&f->f_pos_lockdevice loop0 blocksize: 4096
){+.+.+.}, at: [<ffffffff815d818c>] __fdget_pos+0xac/0xd0 fs/file.c:781
2 locks held by getty/3779:
b_state=0x00000029, b_size=512
 #0: 
device loop0 blocksize: 4096
 (&tty->ldisc_sem){++++++}__find_get_block_slow() failed. block=1, b_blocknr=8
, at: [<ffffffff839f8122>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1: 
device loop0 blocksize: 4096
 (&ldata->atomic_read_lock){+.+...}__find_get_block_slow() failed. block=1, b_blocknr=8
, at: [<ffffffff8211edc2>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142
device loop0 blocksize: 4096
2 locks held by syz-executor0/21426:
 #0: 
__find_get_block_slow() failed. block=1, b_blocknr=8
 (b_state=0x00000029, b_size=512
sb_writersdevice loop0 blocksize: 4096
#11){.+.+.+}, at: [<ffffffff815e0a2f>] sb_start_write include/linux/fs.h:1573 [inline]
#11){.+.+.+}, at: [<ffffffff815e0a2f>] mnt_want_write+0x3f/0xb0 fs/namespace.c:391
 #1: 
b_state=0x00000029, b_size=512
 (device loop0 blocksize: 4096
&sb->s_type->i_mutex_key#17){++++++}__find_get_block_slow() failed. block=1, b_blocknr=8
, at: [<ffffffff8156a838>] inode_lock include/linux/fs.h:766 [inline]
, at: [<ffffffff8156a838>] do_truncate2+0x128/0x1f0 fs/open.c:61
2 locks held by syz-executor0/21432:
device loop0 blocksize: 4096
 #0:  (sb_writers#11
__find_get_block_slow() failed. block=1, b_blocknr=8
){.+.+.+}b_state=0x00000029, b_size=512
, at: [<ffffffff815e0a2f>] sb_start_write include/linux/fs.h:1573 [inline]
, at: [<ffffffff815e0a2f>] mnt_want_write+0x3f/0xb0 fs/namespace.c:391
 #1:  (&sb->s_type->i_mutex_key#17
__find_get_block_slow() failed. block=1, b_blocknr=8
){++++++}b_state=0x00000029, b_size=512
, at: [<ffffffff8156a838>] inode_lock include/linux/fs.h:766 [inline]
, at: [<ffffffff8156a838>] do_truncate2+0x128/0x1f0 fs/open.c:61
2 locks held by syz-executor0/21440:
 #0: 
__find_get_block_slow() failed. block=1, b_blocknr=8
 (b_state=0x00000029, b_size=512
sb_writersdevice loop0 blocksize: 4096
#11){.+.+.+}, at: [<ffffffff815687ab>] sb_start_write include/linux/fs.h:1573 [inline]
#11){.+.+.+}, at: [<ffffffff815687ab>] vfs_fallocate+0x2fb/0x600 fs/open.c:328
 #1: 
b_state=0x00000029, b_size=512
 (device loop0 blocksize: 4096
&sb->s_type->i_mutex_key#17){++++++}__find_get_block_slow() failed. block=1, b_blocknr=8
, at: [<ffffffff818c86de>] inode_lock include/linux/fs.h:766 [inline]
, at: [<ffffffff818c86de>] fat_fallocate+0x10e/0x2d0 fs/fat/file.c:249
2 locks held by syz-executor0/21442:
device loop0 blocksize: 4096
 #0:  (sb_writers#11
__find_get_block_slow() failed. block=1, b_blocknr=8
){.+.+.+}b_state=0x00000029, b_size=512
, at: [<ffffffff815e0a2f>] sb_start_write include/linux/fs.h:1573 [inline]
, at: [<ffffffff815e0a2f>] mnt_want_write+0x3f/0xb0 fs/namespace.c:391
 #1:  (&sb->s_type->i_mutex_key
__find_get_block_slow() failed. block=1, b_blocknr=8
#17b_state=0x00000029, b_size=512
){++++++}device loop0 blocksize: 4096
, at: [<ffffffff8156a838>] inode_lock include/linux/fs.h:766 [inline]
, at: [<ffffffff8156a838>] do_truncate2+0x128/0x1f0 fs/open.c:61
1 lock held by init/21470:
b_state=0x00000029, b_size=512
 #0: 
device loop0 blocksize: 4096
 (tty_mutex){+.+.+.}__find_get_block_slow() failed. block=1, b_blocknr=8
, at: [<ffffffff821191cc>] tty_open_by_driver drivers/tty/tty_io.c:2047 [inline]
, at: [<ffffffff821191cc>] tty_open+0x46c/0xe20 drivers/tty/tty_io.c:2125
1 lock held by init/21471:
device loop0 blocksize: 4096
 #0:  (tty_mutex){+.+.+.}
__find_get_block_slow() failed. block=1, b_blocknr=8
, at: [<ffffffff821191cc>] tty_open_by_driver drivers/tty/tty_io.c:2047 [inline]
, at: [<ffffffff821191cc>] tty_open+0x46c/0xe20 drivers/tty/tty_io.c:2125
1 lock held by init/21472:
device loop0 blocksize: 4096
 #0:  (tty_mutex){+.+.+.}
__find_get_block_slow() failed. block=1, b_blocknr=8
, at: [<ffffffff821191cc>] tty_open_by_driver drivers/tty/tty_io.c:2047 [inline]
, at: [<ffffffff821191cc>] tty_open+0x46c/0xe20 drivers/tty/tty_io.c:2125
1 lock held by init/21473:
device loop0 blocksize: 4096
 #0:  (tty_mutex
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
){+.+.+.}device loop0 blocksize: 4096
, at: [<ffffffff821191cc>] tty_open_by_driver drivers/tty/tty_io.c:2047 [inline]
, at: [<ffffffff821191cc>] tty_open+0x46c/0xe20 drivers/tty/tty_io.c:2125
1 lock held by init/21474:
b_state=0x00000029, b_size=512
 #0: 
device loop0 blocksize: 4096
 (tty_mutex){+.+.+.}, at: [<ffffffff821191cc>] tty_open_by_driver drivers/tty/tty_io.c:2047 [inline]
 (tty_mutex){+.+.+.}, at: [<ffffffff821191cc>] tty_open+0x46c/0xe20 drivers/tty/tty_io.c:2125
1 lock held by init/21475:
b_state=0x00000029, b_size=512
 #0: 
device loop0 blocksize: 4096
 (tty_mutex){+.+.+.}, at: [<ffffffff821191cc>] tty_open_by_driver drivers/tty/tty_io.c:2047 [inline]
 (tty_mutex){+.+.+.}, at: [<ffffffff821191cc>] tty_open+0x46c/0xe20 drivers/tty/tty_io.c:2125

b_state=0x00000029, b_size=512
=============================================

device loop0 blocksize: 4096
NMI backtrace for cpu 0
CPU: 0 PID: 519 Comm: khungtaskd Not tainted 4.9.112-g9e79039 #7
__find_get_block_slow() failed. block=1, b_blocknr=8
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
b_state=0x00000029, b_size=512
 ffff8801d9797d08
device loop0 blocksize: 4096
 ffffffff81eb3249 0000000000000000__find_get_block_slow() failed. block=1, b_blocknr=8
 0000000000000000b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
 0000000000000000 0000000000000001 ffffffff810b9bd0
__find_get_block_slow() failed. block=1, b_blocknr=8
 ffff8801d9797d40b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
 ffffffff81ebe547 0000000000000000
__find_get_block_slow() failed. block=1, b_blocknr=8
 0000000000000000b_state=0x00000029, b_size=512
 0000000000000002device loop0 blocksize: 4096
Call Trace:
 [<ffffffff81eb3249>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81eb3249>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
 [<ffffffff81ebe547>] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
 [<ffffffff81ebe4da>] nmi_trigger_cpumask_backtrace+0x12a/0x14f lib/nmi_backtrace.c:60
b_state=0x00000029, b_size=512
 [<ffffffff810b9cd4>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
device loop0 blocksize: 4096
 [<ffffffff81366cf4>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81366cf4>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81366cf4>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81366cf4>] watchdog+0x6b4/0xa20 kernel/hung_task.c:239
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
 [<ffffffff8119d0bd>] kthread+0x26d/0x300 kernel/kthread.c:211
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
 [<ffffffff839fa11c>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373
b_state=0x00000029, b_size=512
Sending NMI from CPU 0 to CPUs 1:
device loop0 blocksize: 4096
NMI backtrace for cpu 1
CPU: 1 PID: 21391 Comm: syz-executor0 Not tainted 4.9.112-g9e79039 #7
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801ba549800 task.stack: ffff8801add18000
RIP: 0010:[<ffffffff8135ea70>] 
c [<ffffffff8135ea70>] __sanitizer_cov_trace_pc+0x0/0x50
RSP: 0018:ffff8801add1ef90  EFLAGS: 00000202
RAX: 0000000000040000 RBX: ffffea00063db680 RCX: ffffc900008f5000
RDX: 0000000000040000 RSI: ffffffff8143a132 RDI: 0000000000000246
RBP: ffff8801add1efe0 R08: ffff8801ba54a138 R09: 0000000000000001
R10: 0000000000000000 R11: 1ffff100374a9422 R12: 0000000000000001
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8801d61959c8
FS:  00007ff7a7576700(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000014d8b10 CR3: 00000001c897a000 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff8143a3a8
c 0000000000000001
c ffff8801ba54a0c8
c fffffbfff098c478
c
 0000000000000001
c ffff8801d61959c8
c 0000000000000000
c dffffc0000000000
c
 ffff8801bac57498
c ffff8801d61957d0
c ffff8801add1f040
c ffffffff81623f82
c
Call Trace:
 [<ffffffff81623f82>] find_get_page_flags include/linux/pagemap.h:264 [inline]
 [<ffffffff81623f82>] __find_get_block_slow+0xc2/0x330 fs/buffer.c:212
 [<ffffffff8162452e>] __find_get_block+0x23e/0x4c0 fs/buffer.c:1360
 [<ffffffff81625339>] __getblk_slow fs/buffer.c:1101 [inline]
 [<ffffffff81625339>] __getblk_gfp+0x189/0x710 fs/buffer.c:1386
 [<ffffffff81628cdd>] __bread_gfp+0x2d/0x270 fs/buffer.c:1420
 [<ffffffff818c4a1b>] sb_bread include/linux/buffer_head.h:300 [inline]
 [<ffffffff818c4a1b>] fat12_ent_bread+0x13b/0x400 fs/fat/fatent.c:75
 [<ffffffff818c59cf>] fat_ent_read+0x44f/0xa20 fs/fat/fatent.c:367
 [<ffffffff818b662c>] fat_get_cluster+0x6fc/0xbc0 fs/fat/cache.c:259
 [<ffffffff818d6ed5>] fat_chain_add+0x395/0x610 fs/fat/misc.c:113
 [<ffffffff818d40cf>] fat_add_cluster+0xbf/0xe0 fs/fat/inode.c:105
 [<ffffffff818d43cf>] __fat_get_block fs/fat/inode.c:147 [inline]
 [<ffffffff818d43cf>] fat_get_block+0x2df/0x800 fs/fat/inode.c:176
 [<ffffffff81629f21>] __block_write_begin_int+0x391/0x1040 fs/buffer.c:1987
 [<ffffffff8162ac6f>] __block_write_begin fs/buffer.c:2038 [inline]
 [<ffffffff8162ac6f>] block_write_begin+0x5f/0x180 fs/buffer.c:2097
 [<ffffffff8162b283>] cont_write_begin+0x4f3/0x810 fs/buffer.c:2450
 [<ffffffff818d053a>] fat_write_begin+0x9a/0x120 fs/fat/inode.c:222
 [<ffffffff814330bd>] pagecache_write_begin+0x8d/0xc0 mm/filemap.c:2587
 [<ffffffff8162af8f>] cont_expand_zero fs/buffer.c:2375 [inline]
 [<ffffffff8162af8f>] cont_write_begin+0x1ff/0x810 fs/buffer.c:2440
 [<ffffffff818d053a>] fat_write_begin+0x9a/0x120 fs/fat/inode.c:222
 [<ffffffff814330bd>] pagecache_write_begin+0x8d/0xc0 mm/filemap.c:2587
 [<ffffffff81622c70>] generic_cont_expand_simple+0x120/0x170 fs/buffer.c:2338
 [<ffffffff818c83cd>] fat_cont_expand+0x6d/0x270 fs/fat/file.c:193
 [<ffffffff818c8725>] fat_fallocate+0x155/0x2d0 fs/fat/file.c:271
 [<ffffffff81568809>] vfs_fallocate+0x359/0x600 fs/open.c:329
 [<ffffffff8156b713>] SYSC_fallocate fs/open.c:352 [inline]
 [<ffffffff8156b713>] SyS_fallocate+0x53/0x90 fs/open.c:346
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839f9f53>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Code: 
c1d 
c00 
ceb 
c81 
c4c 
c89 
cff 
ce8 
c6f 
cd2 
c1d 
c00 
ce9 
c5f 
cff 
cff 
cff 
c48 
c89 
cdf 
ce8 
cc2 
cd1 
c1d 
c00 
ce9 
cf9 
cfe 
cff 
cff 
c66 
c2e 
c0f 
c1f 
c84 
c00 
c00 
c00 
c00 
c00 
c0f 
c1f 
c00 
c<55> 
c48 
c89 
ce5 
c65 
c48 
c8b 
c04 
c25 
cc0 
c7d 
c01 
c00 
c65 
c8b 
c15 
ccc 
c92 
ccb 
c7e 
c81 
c
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096