Bug 1732691

Hello Red Hat, there is a test BUG for your 7 products, the content is Chinese, please understand


问题复现：
首先 useradd ttt 创建一个账号
然后 su - ttt 进入账户 
这里注意 直接 su 输入密码 进入管理员 （这里就会留下一个BASH的进程）
当 userdel -r ttt 时 就会报错 提示有进程正在使用
解决方案是 ps -ef |grep 报错的PID 查到PID
然后kill -9 PID 
但是这样 内核就会崩溃 然后现在用的BASH也不好使了 就是输入不了命令 都是空格
想问下这个问题是什么原因造成的 还是是系统的BUG原理是什么
以下是演示截图：

go to annex!

PS：正常如果 su - ttt 然后 logout 然后再操作userdel -r ttt是没有问题的
第二次测试的时候 虚拟机 也死了 很恐怖 自己输入了exit  然后就没了~ bash 终端就被关闭了 再打开就可以了

annex：

1.20190723225059Thinkmail

https://p13.zdusercontent.com/attachment/329667/yFzfdr4tjNBPN8iGY1rtpba8v?token=eyJhbGciOiJkaXIiLCJlbmMiOiJBMTI4Q0JDLUhTMjU2In0..HAhY_83QYbMuv5ld7Q8NWg.9UPrZS-J5aX7WOt20Ag_Ds2VMUp3pKe6V-AxbZgxX36oYPLObvNpU_ZY9hw1hd0iWwF4FrefeJwip_UlTklSAhH6ctocW3lSZpNyegppoIOgpw_1B4cNINey_mu_lGchknT-omAKFWU-5I_TPEtbo6Twp95R_I4ELAFSrD33uX4rnyjpU8qIQIJq7TKNM1fVcVqO0NoLZ8QjoPpfJcZHpv7Kcwmau0_t6xyJEb9xnPS5nzGY6y49RPONqTb0CFUMONdPxet_KJTBHwrddn1HSQ.BGOaJnqYycmcjFiTFO8tQg

2.20190723225059Thinkmail

https://p13.zdusercontent.com/attachment/329667/bV3BFNHGfbQMTPVBKpIDzoEM9?token=eyJhbGciOiJkaXIiLCJlbmMiOiJBMTI4Q0JDLUhTMjU2In0..ZXz901xpqD8Pm9201JglJQ.MVJubF72ZvpDnGXsS1iPLSLjQlLeRIXnCkVlN7vQWyA3sl9FbWi1ZLOL_TbWzDi67t5LjDKap2a2x-ipJS0nsUVOBLog2D2x9L9DsEKqK73-3lwfipgFO7Cx9ZslCPsdosBBLtghbmE9B1P04Ex1dRkTKfyvyrAjYjJwVfUld95es3LWxKX_NUyEURfpSNzhNr9sqxkMgxhNGwunqUIaDkynW5d3NbcWNyqIXGR_3ORQaMvy79y7QLfy8GDGSUlNz7B4lw88cLs_wqexLRzYBw.pI7x3Ud4vMZD5IVJjIn07g

3.20190723225059Thinkmail

https://p13.zdusercontent.com/attachment/329667/fn2EVMk474xqgGRwSHL7XboS4?token=eyJhbGciOiJkaXIiLCJlbmMiOiJBMTI4Q0JDLUhTMjU2In0..qeDGIHG-4Ldyp4vtL3mXcQ.rD463STa8zYXKXbDGyDcQ4Q-r9B7RwxBbHKm4wPibCGyw5YLq5pB6AGnc7uLFwu6BO6Fj3gBPMbbfgfMnt3fCUT1DkymlowkAYK47dJEFIyqog_qDW8FKHTH6CCwVCcbIKSiRsEL50UVPik5hm-X1LIZ_6x464AQQqOfrlaFqVvOB9O2blsFhWBDBVuiQdzROCoEUcZYDO7Y8Z5XkVSOMeJuowGSQ6RwIf5qnrCQNbLVnlUfWWgPj8JH2vkwQ1eE4933ZTbhrD4JHonn7qQbBQ.KlZZ4nkqGvv0eOPEdDWBmQ

The attachment is the first time that the connection is automatically sent to the customer service via email.


Problem recurrence:
First useradd ttt create an account
Then su - ttt enters the account
Note here directly su Enter the password Enter the administrator (here will leave a BASH process)
When userdel -r ttt will report an error, indicating that a process is in use.
The solution is ps -ef |grep error PID found PID
Then kill -9 PID
But the kernel will crash, and the BASH that is used now is not good. It is impossible to enter the command.
I want to ask what is the cause of this problem or what is the principle of the system BUG?
The following is a demo screenshot:



PS: Normal if su - ttt then logout and then operate userdel -r ttt is no problem
The second test, the virtual machine is also dead, very scary, I entered the exit and then it is gone~ the bash terminal is closed, and then it can be opened.