Re: [PATCH] tests: fix recent false failure due to a race

[Bernhard Voelker]

On 04/20/2016 06:12 PM, Pádraig Brady wrote:
> * tests/cp/parent-perm-race.sh: This new race introduced in
> commit v8.25-5-g632eda5 is quite hard to hit, but is due to
> `ls > fifo` doing write()/close()/exit() once `cp` has
> open() the source fifo.  Then the subsequent comparison of the
> destination file may fail due to the file being missing or empty.
> Previously `ls` generated output that was independent of `cp`.
> Now we must wait for `cp` to finish before inspecting the
> destination file that it wrote.
> ---
>  tests/cp/parent-perm-race.sh | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/tests/cp/parent-perm-race.sh b/tests/cp/parent-perm-race.sh
> index 0d0841c..8d09329 100755
> --- a/tests/cp/parent-perm-race.sh
> +++ b/tests/cp/parent-perm-race.sh
> @@ -43,6 +43,8 @@ do
>    # $d/attr and has started to read the source file $attr/fifo.
>    timeout 10 sh -c "ls -ld d/$attr >$attr/fifo" || fail=1
>  
> +  wait $pid || fail=1
> +
>    ls_output=$(cat d/$attr/fifo) || fail=1
>    case $attr,$ls_output in
>    ownership,d???--[-S]--[-S]* | \
> @@ -52,8 +54,6 @@ do
>    *)
>      fail=1;;
>    esac
> -
> -  wait $pid || fail=1
>  done
>  
>  Exit $fail
> 

Nice one! ... and a good analysis:
+1

Thanks & have a nice day,
Berny