tty-login fails if another bash is exec'ed in .bashrc: no job control in background

[Tycho Kirchner]

Dear bash-maintainers,


Description:
    When another instance of bash is called *within the .bashrc* using the
    exec-builtin within a tty (e.g. Ctrl+Alt+F1) the following error 
occurs:

    initialize_job_control: no job control in background: Bad file 
descriptor

    On the next keypress the user is logged off. This used to work fine 
in bash 4.4.

Repeat-By:
    Put the following snippet into your .bashrc, but make sure you can 
change that later on,
    because the login fails!

    if [[ -z $foo_exec_test ]]; then
        export foo_exec_test=123
        echo "exec bash"
        exec bash
    fi

Thanks
Best Regards
Tycho


Configuration Information [Automatically generated, do not change]:
Machine: x86_64
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS: -g -O2 
-fdebug-prefix-map=/build/bash-2bxm7h/bash-5.0=. 
-fstack-protector-strong -Wformat -Werror=format-security -Wall 
-Wno-parentheses -Wno-format-security
uname output: Linux debian-dell 4.19.0-8-amd64 #1 SMP Debian 4.19.98-1 
(2020-01-26) x86_64 GNU/Linux
Machine Type: x86_64-pc-linux-gnu

Bash Version: 5.0
Patch Level: 3
Release Status: release