Re: [PATCH 1/2] selftests: Remove forced unbuffering for test running

2019-05-21 Thread shuah 

On 5/20/19 11:21 PM, Takashi Iwai wrote:

On Tue, 21 May 2019 00:37:48 +0200,
Kees Cook wrote:


As it turns out, the "stdbuf" command will actually force all
subprocesses into unbuffered output, and some implementations of "echo"
turn into single-character writes, which utterly wrecks writes to /sys
and /proc files.

Instead, drop the "stdbuf" usage, and for any tests that want explicit
flushing between newlines, they'll have to add "fflush(stdout);" as
needed.

Reported-by: Takashi Iwai 
Fixes: 5c069b6dedef ("selftests: Move test output to diagnostic lines")
Signed-off-by: Kees Cook 


Tested-by: Takashi Iwai 

BTW, this might be specific to shell invocation.  As in the original
discussion thread, it starts working when I replace "echo" with
"/usr/bin/echo".

Still it's not easy to control in a script itself, so dropping the
unbuffered mode is certainly safer, yes.

Thanks!


Thank you both.

I will get this in for next rc.

-- Shuah

Re: [PATCH 1/2] selftests: Remove forced unbuffering for test running

2019-05-20 Thread Takashi Iwai 
On Tue, 21 May 2019 00:37:48 +0200,
Kees Cook wrote:
> 
> As it turns out, the "stdbuf" command will actually force all
> subprocesses into unbuffered output, and some implementations of "echo"
> turn into single-character writes, which utterly wrecks writes to /sys
> and /proc files.
> 
> Instead, drop the "stdbuf" usage, and for any tests that want explicit
> flushing between newlines, they'll have to add "fflush(stdout);" as
> needed.
> 
> Reported-by: Takashi Iwai 
> Fixes: 5c069b6dedef ("selftests: Move test output to diagnostic lines")
> Signed-off-by: Kees Cook 

Tested-by: Takashi Iwai 

BTW, this might be specific to shell invocation.  As in the original
discussion thread, it starts working when I replace "echo" with
"/usr/bin/echo".

Still it's not easy to control in a script itself, so dropping the
unbuffered mode is certainly safer, yes.

Thanks!


Takashi


> ---
>  tools/testing/selftests/kselftest/runner.sh | 12 +---
>  1 file changed, 1 insertion(+), 11 deletions(-)
> 
> diff --git a/tools/testing/selftests/kselftest/runner.sh 
> b/tools/testing/selftests/kselftest/runner.sh
> index eff3ee303d0d..00c9020bdda8 100644
> --- a/tools/testing/selftests/kselftest/runner.sh
> +++ b/tools/testing/selftests/kselftest/runner.sh
> @@ -24,16 +24,6 @@ tap_prefix()
>   fi
>  }
>  
> -# If stdbuf is unavailable, we must fall back to line-at-a-time piping.
> -tap_unbuffer()
> -{
> - if ! which stdbuf >/dev/null ; then
> - "$@"
> - else
> - stdbuf -i0 -o0 -e0 "$@"
> - fi
> -}
> -
>  run_one()
>  {
>   DIR="$1"
> @@ -54,7 +44,7 @@ run_one()
>   echo "not ok $test_num $TEST_HDR_MSG"
>   else
>   cd `dirname $TEST` > /dev/null
> - (tap_unbuffer ./$BASENAME_TEST 2>&1; echo $? >&3) |
> + (./$BASENAME_TEST 2>&1; echo $? >&3) |
>   tap_prefix >&4) 3>&1) |
>   (read xs; exit $xs)) 4>>"$logfile" &&
>   echo "ok $test_num $TEST_HDR_MSG") ||
> -- 
> 2.17.1
>

[PATCH 1/2] selftests: Remove forced unbuffering for test running

2019-05-20 Thread Kees Cook 
As it turns out, the "stdbuf" command will actually force all
subprocesses into unbuffered output, and some implementations of "echo"
turn into single-character writes, which utterly wrecks writes to /sys
and /proc files.

Instead, drop the "stdbuf" usage, and for any tests that want explicit
flushing between newlines, they'll have to add "fflush(stdout);" as
needed.

Reported-by: Takashi Iwai 
Fixes: 5c069b6dedef ("selftests: Move test output to diagnostic lines")
Signed-off-by: Kees Cook 
---
 tools/testing/selftests/kselftest/runner.sh | 12 +---
 1 file changed, 1 insertion(+), 11 deletions(-)

diff --git a/tools/testing/selftests/kselftest/runner.sh 
b/tools/testing/selftests/kselftest/runner.sh
index eff3ee303d0d..00c9020bdda8 100644
--- a/tools/testing/selftests/kselftest/runner.sh
+++ b/tools/testing/selftests/kselftest/runner.sh
@@ -24,16 +24,6 @@ tap_prefix()
fi
 }
 
-# If stdbuf is unavailable, we must fall back to line-at-a-time piping.
-tap_unbuffer()
-{
-   if ! which stdbuf >/dev/null ; then
-   "$@"
-   else
-   stdbuf -i0 -o0 -e0 "$@"
-   fi
-}
-
 run_one()
 {
DIR="$1"
@@ -54,7 +44,7 @@ run_one()
echo "not ok $test_num $TEST_HDR_MSG"
else
cd `dirname $TEST` > /dev/null
-   (tap_unbuffer ./$BASENAME_TEST 2>&1; echo $? >&3) |
+   (./$BASENAME_TEST 2>&1; echo $? >&3) |
tap_prefix >&4) 3>&1) |
(read xs; exit $xs)) 4>>"$logfile" &&
echo "ok $test_num $TEST_HDR_MSG") ||
-- 
2.17.1