[PATCH] test: Clean up stack_fbt test

[eugene.loh@oracle.com]

From: Eugene Loh <eugene.loh@oracle.com>

The idea behind the test is to check the stack() output for some fbt
probe for specific expected frames.  An attempt was made to specify the
exact stack that was expected, but there are too many variations among
kernel versions and so maintaining the test was difficult.  Loosen the
test to check for only a few expected frames.

The test was also checking that stack()'s first 3 frames matched
stack(3), but such a test is already provided by, for example,
    test/unittest/printf/tst.stack.d
    test/unittest/stack/tst.stack.d
So, drop the stack(3) stuff.

Signed-off-by: Eugene Loh <eugene.loh@oracle.com>
---
 test/unittest/stack/tst.stack_fbt.r  |  1 +
 test/unittest/stack/tst.stack_fbt.sh | 89 +++++++---------------------
 2 files changed, 23 insertions(+), 67 deletions(-)
 create mode 100644 test/unittest/stack/tst.stack_fbt.r

diff --git a/test/unittest/stack/tst.stack_fbt.r b/test/unittest/stack/tst.stack_fbt.r
new file mode 100644
index 000000000..2e9ba477f
--- /dev/null
+++ b/test/unittest/stack/tst.stack_fbt.r
@@ -0,0 +1 @@
+success
diff --git a/test/unittest/stack/tst.stack_fbt.sh b/test/unittest/stack/tst.stack_fbt.sh
index 15b85be13..f3d321e7f 100755
--- a/test/unittest/stack/tst.stack_fbt.sh
+++ b/test/unittest/stack/tst.stack_fbt.sh
@@ -5,7 +5,7 @@
 # Licensed under the Universal Permissive License v 1.0 as shown at
 # http://oss.oracle.com/licenses/upl.
 #
-# Test the stack action with default stack depth and depth 3.
+# Check the stack action for expected frames.
 
 dtrace=$1
 
@@ -26,8 +26,6 @@ BEGIN
 fbt::vfs_write:entry
 {
 	stack();
-	printf("first 3 frames\n");
-	stack(3);
 	exit(0);
 }' >& dtrace.out
 
@@ -37,17 +35,16 @@ if [ $? -ne 0 ]; then
 	exit 1
 fi
 
-# Strip out
-# - blank lines
-# - "constprop"
-# - "isra"
+# Ignore blank lines and strip out
+# - ".constprop.[0-9]"
 # - "_after_hwframe"    (x86 starting with UEK8)
-# - pointer values
+# - "+0x[0-9a-f]*$"
+# - leading spaces
 
 awk 'NF != 0 { sub("\\.constprop\\.[0-9]", "");
-               sub("\\.isra\\.[0-9]", "");
                sub("_after_hwframe\\+", "+");
-               sub(/+0x[0-9a-f]*$/, "+{ptr}");
+               sub(/+0x[0-9a-f]*$/, "");
+               sub(/^ */, "");
                print }' dtrace.out > dtrace.post
 if [ $? -ne 0 ]; then
 	echo ERROR: awk failed
@@ -55,77 +52,35 @@ if [ $? -ne 0 ]; then
 	exit 1
 fi
 
-# Figure out what stack to expect.
+# Identify, in order, a few frames we expect to see.
 
-read MAJOR MINOR <<< `uname -r | grep -Eo '^[0-9]+\.[0-9]+' | tr '.' ' '`
-
-if [ $MAJOR -eq 5 -a $MINOR -lt 8 ]; then
-	# up to 5.8
-	KERVER="A"
-else
-	# starting at 5.8
-	KERVER="B"
-fi
-
-if [ $(uname -m) == "x86_64" -a $KERVER == "A" ]; then
-cat << EOF > dtrace.cmp
-              vmlinux\`vfs_write+{ptr}
-              vmlinux\`__x64_sys_write+{ptr}
-              vmlinux\`x64_sys_call+{ptr}
-              vmlinux\`do_syscall_64+{ptr}
-              vmlinux\`entry_SYSCALL_64+{ptr}
-EOF
-elif [ $(uname -m) == "aarch64" -a $KERVER == "A" ]; then
-cat << EOF > dtrace.cmp
-              vmlinux\`vfs_write
-              vmlinux\`__arm64_sys_write+{ptr}
-              vmlinux\`el0_svc_common+{ptr}
-              vmlinux\`el0_svc_handler+{ptr}
-              vmlinux\`el0_svc+{ptr}
-EOF
-elif [ $(uname -m) == "x86_64" -a $KERVER == "B" ]; then
-cat << EOF > dtrace.cmp
-              vmlinux\`vfs_write+{ptr}
-              vmlinux\`ksys_write+{ptr}
-              vmlinux\`do_syscall_64+{ptr}
-              vmlinux\`entry_SYSCALL_64+{ptr}
-EOF
-elif [ $(uname -m) == "aarch64" -a $KERVER == "B" ]; then
-cat << EOF > dtrace.cmp
-              vmlinux\`vfs_write
-              vmlinux\`__arm64_sys_write+{ptr}
-              vmlinux\`invoke_syscall+{ptr}
-              vmlinux\`el0_svc_common+{ptr}
-              vmlinux\`do_el0_svc+{ptr}
-              vmlinux\`el0_svc+{ptr}
-              vmlinux\`el0t_64_sync_handler+{ptr}
-              vmlinux\`el0t_64_sync+{ptr}
-EOF
+if [ $(uname -m) == "x86_64" ]; then
+	frames="vfs_write do_syscall_64 entry_SYSCALL_64"
+elif [ $(uname -m) == "aarch64" ]; then
+	frames="vfs_write __arm64_sys_write el0_svc_common el0_svc"
 else
 	echo ERROR: unrecognized platform
 	uname -r
 	uname -m
 	exit 1
 fi
-
-# Add the first 3 frames a second time.
-
-head -3 dtrace.cmp > dtrace.tmp
-echo first 3 frames >> dtrace.cmp
-cat dtrace.tmp >> dtrace.cmp
+for frame in $frames; do
+	echo 'vmlinux`'$frame >> dtrace.cmp
+done
 
 # Compare results.
 
-if ! diff -q dtrace.cmp dtrace.post; then
-	echo ERROR: results do not match
-	diff dtrace.cmp dtrace.post
-	echo "==== expect"
+diff dtrace.cmp dtrace.post | grep '^<' > missing.frames
+if [ `cat missing.frames | wc -l` -ne 0 ]; then
+	echo ERROR: missing some expected frames
+	echo === expected frames include:
 	cat dtrace.cmp
-	echo "==== actual"
+	echo === actual frames are:
 	cat dtrace.out
+	echo === missing expected frames:
+	cat missing.frames
 	exit 1
 fi
 
 echo success
-
 exit 0
-- 
2.47.3