INFO: task syz-executor0:29965 blocked for more than 120 seconds.
      Not tainted 4.9.96-g71fce1e #10
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor0   D29688 29965   3879 0x00000004
 ffff880192a08000 0000000000000000 ffff8801c4450a80 ffff8801d9a6b000
 ffff8801db321b98 ffff88019586fac8 ffffffff839e240d ffffffff81233817
 0000000000000000 ffff880192a088c0 0000000600000007 ffff8801db322468
Call Trace:
 [<ffffffff839e3a0f>] schedule+0x7f/0x1b0 kernel/sched/core.c:3557
 [<ffffffff839ef048>] __rwsem_down_write_failed_common kernel/locking/rwsem-xadd.c:526 [inline]
 [<ffffffff839ef048>] rwsem_down_write_failed+0x598/0x990 kernel/locking/rwsem-xadd.c:555
 [<ffffffff81ee4e77>] call_rwsem_down_write_failed+0x17/0x30 arch/x86/lib/rwsem.S:105
 [<ffffffff8122a440>] __down_write arch/x86/include/asm/rwsem.h:125 [inline]
 [<ffffffff8122a440>] down_write_nested+0x60/0xa0 kernel/locking/rwsem.c:174
 [<ffffffff815a784a>] inode_lock_nested include/linux/fs.h:801 [inline]
 [<ffffffff815a784a>] filename_create+0x17a/0x490 fs/namei.c:3639
 [<ffffffff815a9f21>] user_path_create fs/namei.c:3697 [inline]
 [<ffffffff815a9f21>] SYSC_mkdirat fs/namei.c:3841 [inline]
 [<ffffffff815a9f21>] SyS_mkdirat fs/namei.c:3833 [inline]
 [<ffffffff815a9f21>] SYSC_mkdir fs/namei.c:3860 [inline]
 [<ffffffff815a9f21>] SyS_mkdir+0xb1/0x260 fs/namei.c:3858
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839f3313>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb

Showing all locks held in the system:
2 locks held by khungtaskd/518:
 #0:  (rcu_read_lock){......}, at: [<ffffffff813646ec>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff813646ec>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff81423ce0>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
2 locks held by getty/3777:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff839f14b2>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+.+.}, at: [<ffffffff8211c792>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2133
2 locks held by syz-executor0/29965:
 #0:  (sb_writers#16){.+.+.+}, at: [<ffffffff815de03f>] sb_start_write include/linux/fs.h:1573 [inline]
 #0:  (sb_writers#16){.+.+.+}, at: [<ffffffff815de03f>] mnt_want_write+0x3f/0xb0 fs/namespace.c:391
 #1:  (&sb->s_type->i_mutex_key#15/1){+.+.+.}, at: [<ffffffff815a784a>] inode_lock_nested include/linux/fs.h:801 [inline]
 #1:  (&sb->s_type->i_mutex_key#15/1){+.+.+.}, at: [<ffffffff815a784a>] filename_create+0x17a/0x490 fs/namei.c:3639
2 locks held by syz-executor0/29967:
 #0:  (sb_writers#16){.+.+.+}, at: [<ffffffff815de03f>] sb_start_write include/linux/fs.h:1573 [inline]
 #0:  (sb_writers#16){.+.+.+}, at: [<ffffffff815de03f>] mnt_want_write+0x3f/0xb0 fs/namespace.c:391
 #1:  (&sb->s_type->i_mutex_key#15/1){+.+.+.}, at: [<ffffffff815a7e73>] inode_lock_nested include/linux/fs.h:801 [inline]
 #1:  (&sb->s_type->i_mutex_key#15/1){+.+.+.}, at: [<ffffffff815a7e73>] do_rmdir+0x293/0x3f0 fs/namei.c:3939
1 lock held by syz-executor0/29970:
 #0:  (&sb->s_type->i_mutex_key#15){++++++}, at: [<ffffffff815924e1>] inode_lock_shared include/linux/fs.h:776 [inline]
 #0:  (&sb->s_type->i_mutex_key#15){++++++}, at: [<ffffffff815924e1>] lookup_slow+0x141/0x470 fs/namei.c:1645
2 locks held by syz-executor0/29971:
 #0:  (sb_writers#16){.+.+.+}, at: [<ffffffff815de03f>] sb_start_write include/linux/fs.h:1573 [inline]
 #0:  (sb_writers#16){.+.+.+}, at: [<ffffffff815de03f>] mnt_want_write+0x3f/0xb0 fs/namespace.c:391
 #1:  (&sb->s_type->i_mutex_key#15/1){+.+.+.}, at: [<ffffffff815a7e73>] inode_lock_nested include/linux/fs.h:801 [inline]
 #1:  (&sb->s_type->i_mutex_key#15/1){+.+.+.}, at: [<ffffffff815a7e73>] do_rmdir+0x293/0x3f0 fs/namei.c:3939
2 locks held by syz-executor0/29978:
 #0:  (sb_writers#16){.+.+.+}, at: [<ffffffff815de03f>] sb_start_write include/linux/fs.h:1573 [inline]
 #0:  (sb_writers#16){.+.+.+}, at: [<ffffffff815de03f>] mnt_want_write+0x3f/0xb0 fs/namespace.c:391
 #1:  (&sb->s_type->i_mutex_key#15/1){+.+.+.}, at: [<ffffffff815a7e73>] inode_lock_nested include/linux/fs.h:801 [inline]
 #1:  (&sb->s_type->i_mutex_key#15/1){+.+.+.}, at: [<ffffffff815a7e73>] do_rmdir+0x293/0x3f0 fs/namei.c:3939
2 locks held by syz-executor0/29979:
 #0:  (sb_writers#16){.+.+.+}, at: [<ffffffff815de03f>] sb_start_write include/linux/fs.h:1573 [inline]
 #0:  (sb_writers#16){.+.+.+}, at: [<ffffffff815de03f>] mnt_want_write+0x3f/0xb0 fs/namespace.c:391
 #1:  (&sb->s_type->i_mutex_key#15/1){+.+.+.}, at: [<ffffffff815a784a>] inode_lock_nested include/linux/fs.h:801 [inline]
 #1:  (&sb->s_type->i_mutex_key#15/1){+.+.+.}, at: [<ffffffff815a784a>] filename_create+0x17a/0x490 fs/namei.c:3639
1 lock held by syz-executor0/29980:
 #0:  (&sb->s_type->i_mutex_key#15){++++++}, at: [<ffffffff815924e1>] inode_lock_shared include/linux/fs.h:776 [inline]
 #0:  (&sb->s_type->i_mutex_key#15){++++++}, at: [<ffffffff815924e1>] lookup_slow+0x141/0x470 fs/namei.c:1645

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

NMI backtrace for cpu 0
CPU: 0 PID: 518 Comm: khungtaskd Not tainted 4.9.96-g71fce1e #10
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d854fd08 ffffffff81eb0b69 0000000000000000 0000000000000000
 0000000000000000 0000000000000001 ffffffff810b7d60 ffff8801d854fd40
 ffffffff81ebbe97 0000000000000000 0000000000000000 0000000000000003
Call Trace:
 [<ffffffff81eb0b69>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81eb0b69>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81ebbe97>] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81ebbe2a>] nmi_trigger_cpumask_backtrace+0x12a/0x14f lib/nmi_backtrace.c:60
 [<ffffffff810b7e64>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff81364c84>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81364c84>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81364c84>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81364c84>] watchdog+0x6b4/0xa20 kernel/hung_task.c:239
 [<ffffffff8119ad5d>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff839f34dc>] 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: 29945 Comm: syz-executor0 Not tainted 4.9.96-g71fce1e #10
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801958a8000 task.stack: ffff8801b5e78000
RIP: 0010:[<ffffffff8135ca4b>] 
c [<ffffffff8135ca4b>] __write_once_size include/linux/compiler.h:272 [inline]
RIP: 0010:[<ffffffff8135ca4b>] 
c [<ffffffff8135ca4b>] __sanitizer_cov_trace_pc+0x4b/0x50 kernel/kcov.c:108
RSP: 0018:ffff8801b5e7f8a0  EFLAGS: 00000246
RAX: 0000000000040000 RBX: 0000000000000010 RCX: ffffc9000099e000
RDX: 0000000000040000 RSI: ffffffff81621b5a RDI: 0000000000000246
RBP: ffff8801b5e7f8a0 R08: ffff8801958a8960 R09: 0000000000000001
R10: 0000000000000000 R11: 1ffff10032b15127 R12: 0000000000000000
R13: dffffc0000000000 R14: ffff8801b9d7b930 R15: 000000000000000f
FS:  00007f7a51eb0700(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f35b56f5140 CR3: 00000001b5436000 CR4: 00000000001606f0
DR0: 0000000020000000 DR1: 0000000020000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Stack:
 ffff8801b5e7f8f0
c ffffffff81621b5a
c 00000200070f4e80
c 0000000000000171
c
 ffff8801d9c13980
c 0000000000000001
c ffffea00070f4e9c
c ffffea00070f4e80
c
 0000000000000200
c dffffc0000000000
c ffff8801b5e7f990
c ffffffff81622989
c
Call Trace:
 [<ffffffff81621b5a>] __find_get_block+0x21a/0x4c0 fs/buffer.c:1366
 [<ffffffff81622989>] __getblk_slow fs/buffer.c:1101 [inline]
 [<ffffffff81622989>] __getblk_gfp+0x189/0x710 fs/buffer.c:1386
 [<ffffffff8162632d>] __bread_gfp+0x2d/0x270 fs/buffer.c:1420
 [<ffffffff818b3d38>] sb_bread include/linux/buffer_head.h:300 [inline]
 [<ffffffff818b3d38>] fat__get_entry+0x4c8/0x8f0 fs/fat/dir.c:100
 [<ffffffff818b69c1>] fat_get_entry fs/fat/dir.c:128 [inline]
 [<ffffffff818b69c1>] fat_get_short_entry+0x131/0x2a0 fs/fat/dir.c:876
 [<ffffffff818b6f1d>] fat_scan+0xfd/0x340 fs/fat/dir.c:961
 [<ffffffff818de529>] msdos_find+0xf9/0x2d0 fs/fat/namei_msdos.c:128
 [<ffffffff818dee45>] msdos_lookup+0x135/0x250 fs/fat/namei_msdos.c:208
 [<ffffffff8159167c>] lookup_real fs/namei.c:1522 [inline]
 [<ffffffff8159167c>] __lookup_hash+0x11c/0x190 fs/namei.c:1542
 [<ffffffff815a7e86>] do_rmdir+0x2a6/0x3f0 fs/namei.c:3940
 [<ffffffff815aa0ea>] SYSC_rmdir fs/namei.c:3969 [inline]
 [<ffffffff815aa0ea>] SyS_rmdir+0x1a/0x20 fs/namei.c:3967
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839f3313>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Code: 
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c<5d> 
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c