[DTrace-devel] [PATCH v7 5/6] usdt: new tests for USDT arg sanity with overlapping pid probes

Eugene Loh eugene.loh at oracle.com
Thu Nov 7 20:54:04 UTC 2024 

On 11/6/24 06:29, Nick Alcock wrote:

> This generalizes the existing tst.pidprobes.sh to check the args
> reported by the probe both with and without arg mapping in place.
>
> Everything seems to work.

That comment seems to be unnecessary.

Also, is there a "dtrace -lv" test for USDT args?  (I'm not even sure if 
that question makes sense.)

> Signed-off-by: Nick Alcock <nick.alcock at oracle.com>
> ---
>   .../usdt/{tst.pidprobes.sh => pidprobes.sh}   | 56 +++++++++++++++----

Why the renaming?  And, will "./runtest.sh" run pidprobes.sh without any 
command-line args?

>   test/unittest/usdt/tst.pidargmap.sh           | 11 ++++
>   test/unittest/usdt/tst.pidargs.sh             | 11 ++++
>   3 files changed, 67 insertions(+), 11 deletions(-)
>   rename test/unittest/usdt/{tst.pidprobes.sh => pidprobes.sh} (82%)
>   create mode 100755 test/unittest/usdt/tst.pidargmap.sh
>   create mode 100755 test/unittest/usdt/tst.pidargs.sh
>
> diff --git a/test/unittest/usdt/tst.pidprobes.sh b/test/unittest/usdt/pidprobes.sh
> similarity index 82%
> rename from test/unittest/usdt/tst.pidprobes.sh
> rename to test/unittest/usdt/pidprobes.sh
> index 25fee85537fc..aedc6256f195 100755
> --- a/test/unittest/usdt/tst.pidprobes.sh
> +++ b/test/unittest/usdt/pidprobes.sh
> @@ -5,9 +5,12 @@
>   # Licensed under the Universal Permissive License v 1.0 as shown at
>   # http://oss.oracle.com/licenses/upl.
>   #
> -# This test verifies that USDT and pid probes can share underlying probes.
> +# This test verifies various properties of USDT and pid probes sharing
> +# underlying probes.
>   
>   dtrace=$1
> +usdt=$2

Why is there a usdt=$2?  It seems that usdt is always "t" and you'd 
expect that in test/unittest/usdt.

> +mapping=$3
>   
>   # Set up test directory.
>   
> @@ -17,13 +20,21 @@ cd $DIRNAME
>   
>   # Create test source files.
>   
> -cat > prov.d <<EOF
> +if [[ -z $mapping ]]; then
> +    cat > prov.d <<EOF
>   provider pyramid {
>   	probe entry(int, char, int, int);
>   };
>   EOF
> +else
> +    cat > prov.d <<EOF
> +provider pyramid {
> +	probe entry(int a, char b, int c, int d) : (int c, int d, int a, char b);
> +};
> +EOF
> +fi
>   
> -cat > main.c <<EOF
> +cat > main.c <<'EOF'
>   #include <stdio.h>
>   #include "prov.h"
>   
> @@ -48,7 +59,7 @@ EOF
>   
>   # Build the test program.
>   
> -$dtrace -h -s prov.d
> +$dtrace $dt_flags -h -s prov.d
>   if [ $? -ne 0 ]; then
>   	echo "failed to generate header file" >&2
>   	exit 1
> @@ -61,12 +72,12 @@ fi
>   if [[ `uname -m` = "aarch64" ]]; then
>   	objdump -d main.o > disasm_foo.txt.before
>   fi
> -$dtrace -G -64 -s prov.d main.o
> +$dtrace $dt_flags -G -64 -s prov.d main.o
>   if [ $? -ne 0 ]; then
>   	echo "failed to create DOF" >&2
>   	exit 1
>   fi
> -cc $test_cppflags -o main main.o prov.o
> +cc $test_ldflags -o main main.o prov.o
>   if [ $? -ne 0 ]; then
>   	echo "failed to link final executable" >&2
>   	exit 1
> @@ -75,7 +86,7 @@ fi
>   # Check that the program output is 0 when the USDT probe is not enabled.
>   # That is, the PYRAMID_ENTRY_ENABLED() is-enabled checks should not pass.
>   
> -./main > main.out
> +./main standalone > main.out

I'd vote against this change.  Introducing a command-line arg that is 
not used?  Or, add it as a comment?  But there is already a comment.

>   echo "my result: 0" > main.out.expected
>   if ! diff -q main.out main.out.expected > /dev/null; then
>   	echo '"my result"' looks wrong when not using DTrace
> @@ -88,11 +99,25 @@ fi
>   
>   # Run dtrace.
>   
> -$dtrace $dt_flags -q -c ./main -o dtrace.out -n '
> +cat >> pidprobes.d <<'EOF'
>   p*d$target::foo:
>   {
>   	printf("%d %s:%s:%s:%s %x\n", pid, probeprov, probemod, probefunc, probename, uregs[R_PC]);
> -}' > main.out2
> +}
> +EOF
> +
> +if [[ -n $usdt ]]; then
> +	echo 'pyramid$target::foo: {' >> pidprobes.d
> +
> +	if [[ -n $mapping ]]; then
> +		echo 'printf("%d %s:%s:%s:%s %i %i %i %c\n", pid, probeprov, probemod, probefunc, probename, args[0], args[1], args[2], args[3]);' >> pidprobes.d
> +	else
> +		echo 'printf("%d %s:%s:%s:%s %i %c %i %i\n", pid, probeprov, probemod, probefunc, probename, args[0], args[1], args[2], args[3]);' >> pidprobes.d
> +	fi
> +	echo '}' >> pidprobes.d
> +fi
> +
> +$dtrace $dt_flags -q -c ./main -o dtrace.out -s pidprobes.d > main.out2
>   if [ $? -ne 0 ]; then
>   	echo "failed to run dtrace" >&2
>   	cat main.out2
> @@ -106,7 +131,7 @@ fi
>   echo "my result: 10" > main.out2.expected
>   
>   if ! diff -q main.out2 main.out2.expected > /dev/null; then
> -	echo '"my result"' looks wrong when using DTrace
> +	echo '"my result"' looks wrong

Why?  In particular, "when using DTrace" stands in contrast to the 
earlier message 'echo '"my result"' looks wrong when not using DTrace'.

>   	echo === got ===
>   	cat main.out2
>   	echo === expected ===
> @@ -262,8 +287,17 @@ for pc in $pcs; do
>   done
>   echo $usdt_pcs | awk '{printf("'$pid' pyramid'$pid':main:foo:entry %x\n", $1);}' >> dtrace.out.expected
>   echo $usdt_pcs | awk '{printf("'$pid' pyramid'$pid':main:foo:entry %x\n", $2);}' >> dtrace.out.expected
> +if [[ -n $usdt ]]; then
> +	if [[ -z $mapping ]]; then
> +		echo "$pid pyramid$pid:main:foo:entry 2 a 16 128" >> dtrace.out.expected
> +		echo "$pid pyramid$pid:main:foo:entry 4 b 32 256" >> dtrace.out.expected
> +	else
> +		echo "$pid pyramid$pid:main:foo:entry 16 128 2 a" >> dtrace.out.expected
> +		echo "$pid pyramid$pid:main:foo:entry 32 256 4 b" >> dtrace.out.expected
> +	fi
> +fi
>   
> -# Sort and check.
> +# Sort and check (dropping any wake-up firings from deferred probing).

I guess I do not get this.  Where does any "dropping" take place?

>   
>   sort dtrace.out          > dtrace.out.sorted
>   sort dtrace.out.expected > dtrace.out.expected.sorted
> diff --git a/test/unittest/usdt/tst.pidargmap.sh b/test/unittest/usdt/tst.pidargmap.sh
> new file mode 100755
> index 000000000000..0c83f8703539
> --- /dev/null
> +++ b/test/unittest/usdt/tst.pidargmap.sh
> @@ -0,0 +1,11 @@
> +#!/bin/bash
> +#
> +# Oracle Linux DTrace.
> +# Copyright (c) 2024, Oracle and/or its affiliates. All rights reserved.
> +# Licensed under the Universal Permissive License v 1.0 as shown at
> +# http://oss.oracle.com/licenses/upl.
> +#
> +# This test verifies that USDT and pid probes that share underlying probes
> +# do not apply arg mappings (incorrectly) to the pid probes.

How do we verify that mappings do not apply (incorrectly) to pid 
probes?  Is there supposed to be a check on pid probe args?

> +
> +exec $(dirname $_test)/pidprobes.sh $1 t t
> diff --git a/test/unittest/usdt/tst.pidargs.sh b/test/unittest/usdt/tst.pidargs.sh
> new file mode 100755
> index 000000000000..53cba7c39624
> --- /dev/null
> +++ b/test/unittest/usdt/tst.pidargs.sh
> @@ -0,0 +1,11 @@
> +#!/bin/bash
> +#
> +# Oracle Linux DTrace.
> +# Copyright (c) 2024, Oracle and/or its affiliates. All rights reserved.
> +# Licensed under the Universal Permissive License v 1.0 as shown at
> +# http://oss.oracle.com/licenses/upl.
> +#
> +# This test verifies that USDT and pid probes that share underlying probes
> +# get the arguments correct for the USDT probes.
> +
> +exec $(dirname $_test)/pidprobes.sh $1 t ""

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