Vsftp Server connection of Oops:setuid error

First, detailed questions:

I am using FTP IP Address login FTP server, the system prompts me to enter the username and password, but still hint: Oops:child died.

Connection closed by remote host.

Server side is used Vsftp, began to think is selinux caused the problem, confirmed a bit selinux has closed, Baidu a lap, no results. All kinds of methods are not good.
The literal meaning seems to be a problem with the UID of the landing user, and there seems to be nothing wrong with the check.
Later transferred to a foreign website, found a clue: because the user can open the maximum number of programs are limited, not enough to cause.
Check with Ulimit-u, only 1024, then execute ulimit-u 10240
confirm after the effective restart Vsftp, and then connect, you can log on normally.

It feels a bit strange that the server should be tuned for these parameters when deployed, how can it now be the default 1024?

Continue to check the other restrictions, there are problems to do a bit of adjustment and write to the file inside, so as not to restart the invalid, the command is as follows:

Echo-ne "
* Soft Nproc 65535
* Hard Nproc 65535
* Soft Nofile 65535
* Hard Nofile 65535
">>/etc/security/limits.conf

Echo-ne "
ULIMIT-HSN 65535
Ulimit-u 30720
Ulimit-n 65535
Ulimit-d Unlimited
Ulimit-m Unlimited
Ulimit-s Unlimited
Ulimit-t Unlimited
Ulimit-v Unlimited
">>/etc/profile

Ulimit Related instructions:

ULIMIT-A Displays the current resource constraint settings.
Ulimit-c sets the maximum value for the core file, in blocks.
The maximum value of the ULIMIT-D Program Data section, in kilobytes.
The largest file the Ulimit-f shell can establish is a block.
Ulimit-h set the limit of the resources, that is, the administrator set the restrictions.
ULIMIT-M Specifies the maximum amount of memory that can be used, in kilobytes.
ULIMIT-N Specifies the maximum number of files that can be opened at the same time.
ULIMIT-P Specifies the size of the pipe buffer, in units of 512 bytes.
ULIMIT-S specifies the upper bound of the stack, in kilobytes.
Ulimit-s set the elasticity limit of the resource.
ULIMIT-T Specifies the maximum amount of CPU time to use, in seconds.
Ulimit-u the maximum number of programs that users can open.
ULIMIT-V Specifies the maximum amount of virtual memory that can be used, in kilobytes.

Ii. Solutions :

1, view the status of SELinux: Sestatus-b | grep FTP

2, in the results of the show can be seen

Ftp_home_dir off

Tftpd_disable_trans off

Like Now we just have to set one of them to on.

3, Setsebool-p Ftpd_disable_trans on or setsebool-p ftp_home_dir on

4, restart Vsftpd:service vsftpd restart

Problem solving