mount:
tmpfs on /tmp type tmpfs (rw)
then
mount -t ext4 /dev/sda3 /tmp
log as below:
Jul 13 03:54:10 localhost kernel: [ 53.871354] mnt_add_count, n 1, count 2
Jul 13 03:54:10 localhost kernel: [ 53.871360] mnt_add_count, n -1, count 1
then open a new window(the tool is SecureCRT , X86), the log as below:
Jul 13 03:54:37 localhost kernel: [ 80.921236] unix_bind sun path /tmp/ssh-LzCqpMaVwG/agent.2754
Jul 13 03:54:37 localhost kernel: [ 80.921250] unix_mknod sun path /tmp/ssh-LzCqpMaVwG/agent.2754
Jul 13 03:54:37 localhost kernel: [ 80.921255] mnt_add_count, n 1, count 2
Jul 13 03:54:37 localhost kernel: [ 80.921273] unix path ssh-LzCqpMaVwG
and the to umount /tmp:
[root@localhost ~]# umount /tmp
umount: /tmp: target is busy
(In some cases useful info about processes that
use the device is found by lsof(8) or fuser(1).)
[root@localhost ~]# lsof /tmp
[root@localhost ~]#
the mnt count was added because the operation of opening a new window,
so can't umount.
the stack as below:
Jul 12 04:01:44 localhost kernel: [ 161.246002] 000000000000c1ff ffff880c466f1e38 ffffffff814cda07 ffff880c466f1e50
Jul 12 04:01:44 localhost kernel: [ 161.246004] ffffffff8116f23e ffff88183bc4ab40 ffff880c466f1ec8 ffffffff814a954e
Jul 12 04:01:44 localhost kernel: [ 161.246006] 0000000000000286 00007fea553bb810 ffff881845562700 ffff881845562700
Jul 12 04:01:44 localhost kernel: [ 161.246008] Call Trace:
Jul 12 04:01:44 localhost kernel: [ 161.246011] [<ffffffff814cda07>] dump_stack+0x19/0x1b
Jul 12 04:01:44 localhost kernel: [ 161.246013] [<ffffffff8116f23e>] mntget+0x5e/0x60
Jul 12 04:01:44 localhost kernel: [ 161.246016] [<ffffffff814a954e>] unix_bind+0x2ae/0x300
Jul 12 04:01:44 localhost kernel: [ 161.246018] [<ffffffff8140a55a>] SyS_bind+0x6a/0xa0
Jul 12 04:01:44 localhost kernel: [ 161.246020] [<ffffffff814dacfc>] ? tracesys+0x7e/0xe2
Jul 12 04:01:44 localhost kernel: [ 161.246022] [<ffffffff814dad5b>] tracesys+0xdd/0xe2
Is this a problem? How can I fix it?