Red Hat Enterprise Linux 7 installation hang up after a command is executed internally from the installer

Issue

• We got a hang issue during Red Hat Enterprise Linux 7 installation.
• There are several patterns about the hang location and the frequency. In an environment with a condition, it seems that it often happens in the same hang location.
  • deadlock after hwclock command was executed
  • deadlock after resize2fs command was executed
• But, all of that has one same pattern.
  • it happens just after a command was executed internally from installer (anaconda).