overlayfs: upperdir is in-use by another mount, mount with '-o index=off' to override exclusive upperdir protection. overlayfs: workdir and upperdir must reside under the same mount overlayfs: failed to create directory ./file1\/work (errno: 30); mounting read-only ===================================== WARNING: bad unlock balance detected! 4.14.158-syzkaller #0 Not tainted overlayfs: upperdir is in-use by another mount, mount with '-o index=off' to override exclusive upperdir protection. ------------------------------------- syz-executor.4/22930 is trying to release lock (sb_writers) at: [] sb_end_write include/linux/fs.h:1500 [inline] [] mnt_drop_write+0x3e/0x50 fs/namespace.c:532 but there are no more locks to release! other info that might help us debug this: 1 lock held by syz-executor.4/22930: #0: (&type->s_umount_key#61/1){+.+.}, at: [] alloc_super fs/super.c:251 [inline] #0: (&type->s_umount_key#61/1){+.+.}, at: [] sget_userns+0x551/0xc30 fs/super.c:516 stack backtrace: CPU: 1 PID: 22930 Comm: syz-executor.4 Not tainted 4.14.158-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x142/0x197 lib/dump_stack.c:58 print_unlock_imbalance_bug kernel/locking/lockdep.c:3548 [inline] print_unlock_imbalance_bug.cold+0x114/0x123 kernel/locking/lockdep.c:3525 __lock_release kernel/locking/lockdep.c:3765 [inline] lock_release+0x616/0x940 kernel/locking/lockdep.c:4013 percpu_up_read_preempt_enable include/linux/percpu-rwsem.h:102 [inline] percpu_up_read include/linux/percpu-rwsem.h:108 [inline] __sb_end_write+0xc1/0x100 fs/super.c:1329 sb_end_write include/linux/fs.h:1500 [inline] mnt_drop_write+0x3e/0x50 fs/namespace.c:532 ovl_workdir_create.cold+0x101/0x10d fs/overlayfs/super.c:546 ovl_fill_super+0x100c/0x2660 fs/overlayfs/super.c:988 mount_nodev+0x52/0xf0 fs/super.c:1180 ovl_mount+0x2d/0x40 fs/overlayfs/super.c:1204 mount_fs+0x97/0x2a1 fs/super.c:1237 vfs_kern_mount.part.0+0x5e/0x3d0 fs/namespace.c:1046 vfs_kern_mount fs/namespace.c:1036 [inline] do_new_mount fs/namespace.c:2549 [inline] do_mount+0x417/0x27d0 fs/namespace.c:2879 SYSC_mount fs/namespace.c:3095 [inline] SyS_mount+0xab/0x120 fs/namespace.c:3072 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x45a6f9 RSP: 002b:00007f47dc496c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 000000000045a6f9 RDX: 00000000200000c0 RSI: 0000000020000000 RDI: 000000000040000f RBP: 000000000075bf20 R08: 0000000020000100 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f47dc4976d4 R13: 00000000004c7a83 R14: 00000000004de918 R15: 00000000ffffffff overlayfs: upper fs is r/o, try multi-lower layers mount kobject: 'loop0' (ffff8880a40554a0): kobject_uevent_env ------------[ cut here ]------------ WARNING: CPU: 0 PID: 7230 at fs/namespace.c:1178 cleanup_mnt+0x104/0x150 fs/namespace.c:1178 kobject: 'loop0' (ffff8880a40554a0): fill_kobj_path: path = '/devices/virtual/block/loop0'