FAT-fs (loop6): bogus number of reserved sectors
FAT-fs (loop6): Can't find a valid FAT filesystem
INFO: task syz-executor2:3993 blocked for more than 140 seconds.
      Not tainted 4.9.112-g9e79039 #7
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor2   D27496  3993  27711 0x00000004
 ffff88019e92c800 ffff8801d9ae0000 ffff8801d9ae0000 ffff8801778f3000
 ffff8801db221c18 ffff88018807f988 ffffffff839e907d ffffffff81235667
 0000000000000000 ffff88019e92d0c0 0000000600000007 ffff8801db2224e8
Call Trace:
 [<ffffffff839ea67f>] schedule+0x7f/0x1b0 kernel/sched/core.c:3557
 [<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
 [<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
 [<ffffffff815f0f8b>] inode_lock include/linux/fs.h:766 [inline]
 [<ffffffff815f0f8b>] vfs_setxattr+0x8b/0xe0 fs/xattr.c:218
 [<ffffffff815f119c>] setxattr+0x1bc/0x270 fs/xattr.c:449
 [<ffffffff815f13b7>] path_setxattr+0x167/0x180 fs/xattr.c:468
 [<ffffffff815f177b>] SYSC_setxattr fs/xattr.c:483 [inline]
 [<ffffffff815f177b>] SyS_setxattr+0x3b/0x50 fs/xattr.c:479
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839f9f53>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb

Showing all locks held in the system:
2 locks held by khungtaskd/520:
 #0:  (rcu_read_lock){......}, at: [<ffffffff8136675c>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff8136675c>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff81425de7>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
1 lock held by rsyslogd/3688:
 #0:  (&f->f_pos_lock){+.+.+.}, at: [<ffffffff815d818c>] __fdget_pos+0xac/0xd0 fs/file.c:781
2 locks held by getty/3784:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff839f8122>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff8211edc2>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142
2 locks held by syz-executor2/3993:
 #0:  (sb_writers#15){.+.+.+}, at: [<ffffffff815e0a2f>] sb_start_write include/linux/fs.h:1573 [inline]
 #0:  (sb_writers#15){.+.+.+}, at: [<ffffffff815e0a2f>] mnt_want_write+0x3f/0xb0 fs/namespace.c:391
 #1:  (&type->i_mutex_dir_key#4){++++++}, at: [<ffffffff815f0f8b>] inode_lock include/linux/fs.h:766 [inline]
 #1:  (&type->i_mutex_dir_key#4){++++++}, at: [<ffffffff815f0f8b>] vfs_setxattr+0x8b/0xe0 fs/xattr.c:218
2 locks held by syz-executor2/4044:
 #0:  (sb_writers#15){.+.+.+}, at: [<ffffffff815e0a2f>] sb_start_write include/linux/fs.h:1573 [inline]
 #0:  (sb_writers#15){.+.+.+}, at: [<ffffffff815e0a2f>] mnt_want_write+0x3f/0xb0 fs/namespace.c:391
 #1:  (&type->i_mutex_dir_key#4){++++++}, at: [<ffffffff815f0f8b>] inode_lock include/linux/fs.h:766 [inline]
 #1:  (&type->i_mutex_dir_key#4){++++++}, at: [<ffffffff815f0f8b>] vfs_setxattr+0x8b/0xe0 fs/xattr.c:218

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

NMI backtrace for cpu 0
CPU: 0 PID: 520 Comm: khungtaskd Not tainted 4.9.112-g9e79039 #7
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d8427d08 ffffffff81eb3249 0000000000000000 0000000000000000
 0000000000000000 0000000000000001 ffffffff810b9bd0 ffff8801d8427d40
 ffffffff81ebe547 0000000000000000 0000000000000000 0000000000000002
Call Trace:
 [<ffffffff81eb3249>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81eb3249>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81ebe547>] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81ebe4da>] nmi_trigger_cpumask_backtrace+0x12a/0x14f lib/nmi_backtrace.c:60
 [<ffffffff810b9cd4>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<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
 [<ffffffff8119d0bd>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff839fa11c>] 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: 4041 Comm: syz-executor2 Not tainted 4.9.112-g9e79039 #7
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff88019de36000 task.stack: ffff88019ec98000
RIP: 0010:[<ffffffff812364c8>] 
c [<ffffffff812364c8>] __lock_acquire+0x2f8/0x4070 kernel/locking/lockdep.c:3287
RSP: 0018:ffff88019ec9f4f0  EFLAGS: 00000046
RAX: dffffc0000000000 RBX: ffff88019de36918 RCX: 0000000000000000
RDX: 1ffff10033bc6d24 RSI: 0000000000000490 RDI: ffff88019de36920
RBP: ffff88019ec9f6a0 R08: 0000000000000001 R09: 0000000000000001
R10: ffff88019de36000 R11: 1ffff10033bc6d22 R12: 0000000000000490
R13: 0000000000000002 R14: ffff8801d4632a08 R15: 0000000000000000
FS:  00007f37e62ed700(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c42d2d5010 CR3: 00000001d56c3000 CR4: 00000000001606f0
DR0: 0000000020000000 DR1: 0000000020000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Stack:
 0000000000000001
c ffff88019de368c8
c ffffed0033bc6d18
c ffff88019de36000
c
 dffffc0000000000
c ffff88019ec9f568
c ffffffff81235667
c 0000000000000000
c
 ffff88019de368c0
c 0000000600000007
c ffffffff85604150
c ffffffff839f9bc7
c
Call Trace:
 [<ffffffff8123acb0>] lock_acquire+0x130/0x3e0 kernel/locking/lockdep.c:3756
 [<ffffffff839f9e9e>] __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:112 [inline]
 [<ffffffff839f9e9e>] _raw_spin_lock_irqsave+0x4e/0x62 kernel/locking/spinlock.c:159
 [<ffffffff812215db>] prepare_to_wait_event+0x6b/0x450 kernel/sched/wait.c:213
 [<ffffffff81907b5e>] request_wait_answer+0x22e/0x6e0 fs/fuse/dev.c:459
 [<ffffffff81908669>] __fuse_request_send+0x109/0x1b0 fs/fuse/dev.c:480
 [<ffffffff8190876d>] fuse_request_send+0x5d/0x70 fs/fuse/dev.c:493
 [<ffffffff819129c4>] fuse_simple_request+0x2f4/0x660 fs/fuse/dev.c:551
 [<ffffffff8193a0d8>] fuse_setxattr+0x1e8/0x310 fs/fuse/xattr.c:37
 [<ffffffff8193ad1b>] fuse_xattr_set+0x3b/0x70 fs/fuse/xattr.c:192
 [<ffffffff815ef2be>] __vfs_setxattr+0x10e/0x170 fs/xattr.c:149
 [<ffffffff815f0c72>] __vfs_setxattr_noperm+0x102/0x390 fs/xattr.c:180
 [<ffffffff815f0fbe>] vfs_setxattr+0xbe/0xe0 fs/xattr.c:223
 [<ffffffff815f119c>] setxattr+0x1bc/0x270 fs/xattr.c:449
 [<ffffffff815f13b7>] path_setxattr+0x167/0x180 fs/xattr.c:468
 [<ffffffff815f177b>] SYSC_setxattr fs/xattr.c:483 [inline]
 [<ffffffff815f177b>] SyS_setxattr+0x3b/0x50 fs/xattr.c:479
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839f9f53>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Code: 
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