[LTP] [PATCH v2] test_children_cleanup.sh: Fix race condition

[Li Wang]

On Tue, Feb 15, 2022 at 8:18 PM Cyril Hrubis <chrubis@suse.cz> wrote:

> Hi!
> > Processes can stay alive for a short while even after receiving SIGKILL.
> > Give the child in subprocess cleanup libtest up to 5 seconds to fully
> exit
> > or change state to zombie before reporting that it was left behind.
> >
> > Signed-off-by: Martin Doucha <mdoucha@suse.cz>
> > ---
> >
> > Changes since v1: Report success even if the child gets stuck in zombie
> state
> >
> >  lib/newlib_tests/test_children_cleanup.sh | 23 +++++++++++++++++------
> >  1 file changed, 17 insertions(+), 6 deletions(-)
> >
> > diff --git a/lib/newlib_tests/test_children_cleanup.sh
> b/lib/newlib_tests/test_children_cleanup.sh
> > index 4b4e8b2f0..23408c1bc 100755
> > --- a/lib/newlib_tests/test_children_cleanup.sh
> > +++ b/lib/newlib_tests/test_children_cleanup.sh
> > @@ -10,10 +10,21 @@ rm "$TMPFILE"
> >  if [ "x$CHILD_PID" = "x" ]; then
> >       echo "TFAIL: Child process was not created"
> >       exit 1
> > -elif ! kill -s 0 $CHILD_PID &>/dev/null; then
> > -     echo "TPASS: Child process was cleaned up"
> > -     exit 0
> > -else
> > -     echo "TFAIL: Child process was left behind"
> > -     exit 1
> >  fi
> > +
> > +# The child process can stay alive for a short while even after
> receiving
> > +# SIGKILL, especially if the system is under heavy load. Wait up to 5
> seconds
> > +# for it to fully exit.
> > +for i in `seq 6`; do
> > +     CHILD_STATE=`sed -ne 's/^State:\s*\([A-Z]\).*$/\1/p'
> "/proc/$CHILD_PID/status" 2>/dev/null`
> > +
> > +     if [ ! -e "/proc/$CHILD_PID" ] || [ "x$CHILD_STATE" = "xZ" ]; then
>
> As long as we have the variable inside the quotes there is no point in
> adding the 'x'.
>

Pushed with a note added and this fix. Thanks~

-- 
Regards,
Li Wang
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