syzbot

FAT-fs (loop2): bogus logical sector size 1792
FAT-fs (loop2): Can't find a valid FAT filesystem
INFO: task syz-executor.0:7236 blocked for more than 140 seconds.
      Not tainted 4.9.192+ #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.0  D28552  7236  32287 0x00000000
 0000000000000087 ffff8801d5e60000 0000000000000000 ffff8801db621000
 ffffffff83031180 ffff8801db621018 ffff88018e807730 ffffffff8281ac3e
 ffffffff81569f2a ffff8801d9f950e8 00ff88018e807680 ffff8801db6218f0
Call Trace:
 [<0000000091b86ee5>] schedule+0x92/0x1c0 kernel/sched/core.c:3546
 [<000000003efcc4e8>] d_wait_lookup fs/dcache.c:2450 [inline]
 [<000000003efcc4e8>] d_alloc_parallel+0x10af/0x1720 fs/dcache.c:2532
 [<0000000055ec7bd6>] lookup_open+0x4d1/0x18d0 fs/namei.c:3259
 [<000000007cf8ff2a>] do_last fs/namei.c:3440 [inline]
 [<000000007cf8ff2a>] path_openat+0x16cf/0x2f60 fs/namei.c:3665
 [<00000000e5c59cd1>] do_filp_open+0x1a1/0x280 fs/namei.c:3699
 [<00000000b30f63bf>] do_sys_open+0x2f0/0x610 fs/open.c:1097
 [<00000000feb0e5c9>] SYSC_openat fs/open.c:1124 [inline]
 [<00000000feb0e5c9>] SyS_openat+0x30/0x40 fs/open.c:1118
 [<0000000090fa6375>] do_syscall_64+0x1ad/0x5c0 arch/x86/entry/common.c:288
 [<000000005145e18a>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb

Showing all locks held in the system:
2 locks held by khungtaskd/24:
 #0:  (rcu_read_lock){......}, at: [<000000005c7be1d7>] check_hung_uninterruptible_tasks kernel/hung_task.c:169 [inline]
 #0:  (rcu_read_lock){......}, at: [<000000005c7be1d7>] watchdog+0x14b/0xaf0 kernel/hung_task.c:263
 #1:  (tasklist_lock){.+.+..}, at: [<00000000b863f87f>] debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4336
2 locks held by rs:main Q:Reg/1901:
 #0:  (&f->f_pos_lock){+.+.+.}, at: [<00000000d4c531a6>] __fdget_pos+0xa8/0xd0 fs/file.c:782
 #1:  (sb_writers#4){.+.+.+}, at: [<000000006a4e9936>] file_start_write include/linux/fs.h:2646 [inline]
 #1:  (sb_writers#4){.+.+.+}, at: [<000000006a4e9936>] vfs_write+0x3e9/0x520 fs/read_write.c:558
1 lock held by rsyslogd/1903:
 #0:  (&f->f_pos_lock){+.+.+.}, at: [<00000000d4c531a6>] __fdget_pos+0xa8/0xd0 fs/file.c:782
2 locks held by getty/2031:
 #0:  (&tty->ldisc_sem){++++++}, at: [<00000000b0954cc2>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<000000001ef0872c>] n_tty_read+0x1fe/0x1820 drivers/tty/n_tty.c:2156
3 locks held by syz-executor.1/1285:
 #0:  (sb_writers#14){.+.+.+}, at: [<000000007a5731b0>] sb_start_write include/linux/fs.h:1579 [inline]
 #0:  (sb_writers#14){.+.+.+}, at: [<000000007a5731b0>] mnt_want_write+0x3f/0xb0 fs/namespace.c:391
 #1:  (&type->i_mutex_dir_key#7){++++++}, at: [<0000000052984a9d>] inode_lock include/linux/fs.h:771 [inline]
 #1:  (&type->i_mutex_dir_key#7){++++++}, at: [<0000000052984a9d>] do_last fs/namei.c:3437 [inline]
 #1:  (&type->i_mutex_dir_key#7){++++++}, at: [<0000000052984a9d>] path_openat+0xe4b/0x2f60 fs/namei.c:3665
 #2:  (&fi->mutex){+.+.+.}, at: [<00000000d90cdb61>] fuse_lock_inode+0xad/0xe0 fs/fuse/inode.c:364
2 locks held by syz-executor.1/1481:
 #0:  (&type->i_mutex_dir_key#7){++++++}, at: [<00000000b1715d43>] inode_lock_shared include/linux/fs.h:781 [inline]
 #0:  (&type->i_mutex_dir_key#7){++++++}, at: [<00000000b1715d43>] do_last fs/namei.c:3439 [inline]
 #0:  (&type->i_mutex_dir_key#7){++++++}, at: [<00000000b1715d43>] path_openat+0x16a8/0x2f60 fs/namei.c:3665
 #1:  (&fi->mutex){+.+.+.}, at: [<00000000d90cdb61>] fuse_lock_inode+0xad/0xe0 fs/fuse/inode.c:364
2 locks held by syz-executor.1/1638:
 #0:  (&type->i_mutex_dir_key#7){++++++}, at: [<00000000b1715d43>] inode_lock_shared include/linux/fs.h:781 [inline]
 #0:  (&type->i_mutex_dir_key#7){++++++}, at: [<00000000b1715d43>] do_last fs/namei.c:3439 [inline]
 #0:  (&type->i_mutex_dir_key#7){++++++}, at: [<00000000b1715d43>] path_openat+0x16a8/0x2f60 fs/namei.c:3665
 #1:  (&fi->mutex){+.+.+.}, at: [<00000000d90cdb61>] fuse_lock_inode+0xad/0xe0 fs/fuse/inode.c:364
2 locks held by syz-executor.1/1777:
 #0:  (&type->i_mutex_dir_key#7){++++++}, at: [<00000000b1715d43>] inode_lock_shared include/linux/fs.h:781 [inline]
 #0:  (&type->i_mutex_dir_key#7){++++++}, at: [<00000000b1715d43>] do_last fs/namei.c:3439 [inline]
 #0:  (&type->i_mutex_dir_key#7){++++++}, at: [<00000000b1715d43>] path_openat+0x16a8/0x2f60 fs/namei.c:3665
 #1:  (&fi->mutex){+.+.+.}, at: [<00000000d90cdb61>] fuse_lock_inode+0xad/0xe0 fs/fuse/inode.c:364
2 locks held by syz-executor.1/2123:
 #0:  (&type->i_mutex_dir_key#7){++++++}, at: [<00000000b1715d43>] inode_lock_shared include/linux/fs.h:781 [inline]
 #0:  (&type->i_mutex_dir_key#7){++++++}, at: [<00000000b1715d43>] do_last fs/namei.c:3439 [inline]
 #0:  (&type->i_mutex_dir_key#7){++++++}, at: [<00000000b1715d43>] path_openat+0x16a8/0x2f60 fs/namei.c:3665
 #1:  (&fi->mutex){+.+.+.}, at: [<00000000d90cdb61>] fuse_lock_inode+0xad/0xe0 fs/fuse/inode.c:364
2 locks held by syz-executor.1/2905:
 #0:  (&type->i_mutex_dir_key#7){++++++}, at: [<00000000b1715d43>] inode_lock_shared include/linux/fs.h:781 [inline]
 #0:  (&type->i_mutex_dir_key#7){++++++}, at: [<00000000b1715d43>] do_last fs/namei.c:3439 [inline]
 #0:  (&type->i_mutex_dir_key#7){++++++}, at: [<00000000b1715d43>] path_openat+0x16a8/0x2f60 fs/namei.c:3665
 #1:  (&fi->mutex){+.+.+.}, at: [<00000000d90cdb61>] fuse_lock_inode+0xad/0xe0 fs/fuse/inode.c:364
2 locks held by syz-executor.1/3099:
 #0:  (&type->i_mutex_dir_key#7){++++++}, at: [<00000000b1715d43>] inode_lock_shared include/linux/fs.h:781 [inline]
 #0:  (&type->i_mutex_dir_key#7){++++++}, at: [<00000000b1715d43>] do_last fs/namei.c:3439 [inline]
 #0:  (&type->i_mutex_dir_key#7){++++++}, at: [<00000000b1715d43>] path_openat+0x16a8/0x2f60 fs/namei.c:3665
 #1:  (&fi->mutex){+.+.+.}, at: [<00000000d90cdb61>] fuse_lock_inode+0xad/0xe0 fs/fuse/inode.c:364
2 locks held by syz-executor.1/3290:
 #0:  (&type->i_mutex_dir_key#7){++++++}, at: [<00000000b1715d43>] inode_lock_shared include/linux/fs.h:781 [inline]
 #0:  (&type->i_mutex_dir_key#7){++++++}, at: [<00000000b1715d43>] do_last fs/namei.c:3439 [inline]
 #0:  (&type->i_mutex_dir_key#7){++++++}, at: [<00000000b1715d43>] path_openat+0x16a8/0x2f60 fs/namei.c:3665
 #1:  (&fi->mutex){+.+.+.}, at: [<00000000d90cdb61>] fuse_lock_inode+0xad/0xe0 fs/fuse/inode.c:364
2 locks held by syz-executor.0/7006:
 #0:  (&type->i_mutex_dir_key#7){++++++}, at: [<00000000b1715d43>] inode_lock_shared include/linux/fs.h:781 [inline]
 #0:  (&type->i_mutex_dir_key#7){++++++}, at: [<00000000b1715d43>] do_last fs/namei.c:3439 [inline]
 #0:  (&type->i_mutex_dir_key#7){++++++}, at: [<00000000b1715d43>] path_openat+0x16a8/0x2f60 fs/namei.c:3665
 #1:  (&fi->mutex){+.+.+.}, at: [<00000000d90cdb61>] fuse_lock_inode+0xad/0xe0 fs/fuse/inode.c:364
2 locks held by syz-executor.0/7230:
 #0:  (&type->i_mutex_dir_key#7){++++++}, at: [<000000006511c369>] inode_lock_shared include/linux/fs.h:781 [inline]
 #0:  (&type->i_mutex_dir_key#7){++++++}, at: [<000000006511c369>] lookup_slow+0x160/0x480 fs/namei.c:1770
 #1:  (&fi->mutex){+.+.+.}, at: [<00000000d90cdb61>] fuse_lock_inode+0xad/0xe0 fs/fuse/inode.c:364
1 lock held by syz-executor.0/7236:
 #0:  (&type->i_mutex_dir_key#7){++++++}, at: [<00000000b1715d43>] inode_lock_shared include/linux/fs.h:781 [inline]
 #0:  (&type->i_mutex_dir_key#7){++++++}, at: [<00000000b1715d43>] do_last fs/namei.c:3439 [inline]
 #0:  (&type->i_mutex_dir_key#7){++++++}, at: [<00000000b1715d43>] path_openat+0x16a8/0x2f60 fs/namei.c:3665
2 locks held by syz-executor.0/8438:
 #0:  (&type->i_mutex_dir_key#7){++++++}, at: [<000000006511c369>] inode_lock_shared include/linux/fs.h:781 [inline]
 #0:  (&type->i_mutex_dir_key#7){++++++}, at: [<000000006511c369>] lookup_slow+0x160/0x480 fs/namei.c:1770
 #1:  (&fi->mutex){+.+.+.}, at: [<00000000d90cdb61>] fuse_lock_inode+0xad/0xe0 fs/fuse/inode.c:364

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

NMI backtrace for cpu 0
CPU: 0 PID: 24 Comm: khungtaskd Not tainted 4.9.192+ #0
 ffff8801d98d7cc8 ffffffff81b67081 0000000000000000 0000000000000000
 0000000000000000 ffffffff81099e01 dffffc0000000000 ffff8801d98d7d00
 ffffffff81b7231c 0000000000000000 0000000000000000 0000000000000000
Call Trace:
 [<00000000f25dae6f>] __dump_stack lib/dump_stack.c:15 [inline]
 [<00000000f25dae6f>] dump_stack+0xc1/0x120 lib/dump_stack.c:51
 [<0000000049e55695>] nmi_cpu_backtrace.cold+0x47/0x87 lib/nmi_backtrace.c:99
 [<00000000c5076d15>] nmi_trigger_cpumask_backtrace+0x124/0x155 lib/nmi_backtrace.c:60
 [<00000000a5eee7da>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<000000000bf12154>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<000000000bf12154>] check_hung_task kernel/hung_task.c:126 [inline]
 [<000000000bf12154>] check_hung_uninterruptible_tasks kernel/hung_task.c:183 [inline]
 [<000000000bf12154>] watchdog+0x670/0xaf0 kernel/hung_task.c:263
 [<00000000fa3e817f>] kthread+0x278/0x310 kernel/kthread.c:211
 [<00000000a974ab79>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:375
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1 skipped: idling at pc 0xffffffff82829d91