bash unresponsive after Ctrl-Z interrupts a backquoted command

[Bruno Haible]

Hi,

This command takes about 2 seconds to complete (on a slow machine; you can
make it a triple loop for a faster machine):

foo=`rm -f empty; touch empty; \
     for a in 0 1 2 3 4 5 6 7 8 9 ; do \
       for b in 0 1 2 3 4 5 6 7 8 9 ; do \
         echo g$a$b | cat; \
       done; \
     done | LC_ALL=C uniq -d`

When in bash-3.2.33, I run this command interactively (copy&paste), it
completes fine. When I interrupt it through Ctrl-Z, the CPU consumption
goes down but bash does not issue a prompt and does not respond to keypresses
such as Ctrl-Z nor Ctrl-C.

In fact, the 'echo' (bash), 'cat', 'uniq -d' processes are stopped. But I need
another shell to find out about. This is not very user-friendly.

Could bash issue some prompt, like it does when a non-backquoted 'for'
loop is interrupted?

Bruno