HP-UX exec tee hanging/not working intermittently

[Andrew Resch]

Configuration Information [Automatically generated, do not change]:
Machine: ia64
OS: hpux11.31
Compiler: cc
Compilation CFLAGS:  -DPROGRAM='bash' -DCONF_HOSTTYPE='ia64'
-DCONF_OSTYPE='hpux11.31' -DCONF_MACHTYPE='ia64-hp-hpux11.31'
-DCONF_VENDOR='hp' -DLOCALEDIR='/u
sr/local/share/locale' -DPACKAGE='bash' -DSHELL -DHAVE_CONFIG_H -DHPUX
  -I.  -I. -I./include -I./lib   -O -I/usr/local/include
-D_XOPEN_SOURCE_EXTENDED
uname output: HP-UX van-saml B.11.31 U ia64 3018224905 unlimited-user license
Machine Type: ia64-hp-hpux11.31

Bash Version: 4.2
Patch Level: 10
Release Status: release

Description:
        I am attempting to use exec and tee to have my scripts
stdout/stderr appended to a log file like such: exec > >(tee -a $LOG)
2>&1
        These scripts will often call other scripts with a similar
exec statement, often writing to a separate log file.  On my GNU/Linux
systems,
        these scripts will run just fine without any issue, but on
HP-UX they seem to hang or not display any output.

Repeat-By:

$ cat test_exec1.sh
#!/bin/bash

LOG="test_exec.log"
exec > >(/usr/bin/tee -a $LOG) 2>&1

echo "i am exec1.."

./test_exec2.sh

echo "i am done in exec1.."

$ cat test_exec2.sh
#!/bin/bash

LOG="test_exec2.log"
exec > >(/usr/bin/tee -a $LOG) 2>&1

echo "i am exec2.."

echo "i am done in exec2.."


On one of my HP-UX hosts I can run this script many times before it hangs.

$ while true; do ./test_exec1.sh; done
i am exec1..
i am done in exec1..
i am exec2..
i am done in exec2..
...snip lots of repeats...
i am done in exec1..
i am exec2..
i am done in exec2..
i am exec1..
<hangs here, ctrl+c to end>
$ echo $?
130

On the following host it hangs much more quickly and we don't in fact
get any output from test_exec2.sh script.

$ while true; do ./test_exec1.sh; done
i am exec1..
i am done in exec1..
i am exec1..
i am done in exec1..
i am exec1..
i am done in exec1..
i am exec1..
i am done in exec1..
i am exec1..
i am done in exec1..
i am exec1..
i am done in exec1..
i am exec1..
i am done in exec1..
i am exec1..
i am done in exec1..
i am exec1..
i am done in exec1..
i am exec1..
i am done in exec1..
<hangs here, ctrl+c to end>
$ echo $?
130

Other times it just refuses to run at all:

$ ./test_exec1.sh
$ echo $?
141


I'd really appreciate some guidance on this issue, if you believe it
is a bash bug or if in fact it's purely an issue with HP-UX or system
configuration.  If its helpful, I can provide tusc output for these
commands.

Thank you.