From: Darrick J. Wong <djwong@xxxxxxxxxx>
Support collecting kernel code coverage information as reported in
debugfs. At the start of each section, we reset the gcov counters;
during the section wrapup, we'll collect the kernel gcov data.
If lcov is installed and the kernel source code is available, it will
also generate a nice html report. If a CLI web browser is available, it
will also format the html report into text for easy grepping.
This requires the test runner to set REPORT_GCOV=1 explicitly and gcov
to be enabled in the kernel.
Cc: tytso@xxxxxxx
Cc: kent.overstreet@xxxxxxxxx
Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
---
README | 3 ++
check | 18 ++++++++++++
common/gcov | 87 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 108 insertions(+)
create mode 100644 common/gcov
diff --git a/README b/README
index d4ec73d10d..966ec48ed6 100644
--- a/README
+++ b/README
@@ -249,6 +249,9 @@ Kernel/Modules related configuration:
to "forever" and we'll wait forever until the module is gone.
- Set KCONFIG_PATH to specify your preferred location of kernel config
file. The config is used by tests to check if kernel feature is enabled.
+ - Set REPORT_GCOV to a directory path to make lcov and genhtml generate
+ html reports from any gcov code coverage data collected by the kernel.
+ If REPORT_GCOV is set to 1, the report will be written to $REPORT_DIR/gcov/.
Test control:
- Set LOAD_FACTOR to a nonzero positive integer to increase the amount of
diff --git a/check b/check
index c02e693642..9741be23c4 100755
--- a/check
+++ b/check
@@ -451,6 +451,11 @@ _global_log() {
fi
}
+if [ -n "$REPORT_GCOV" ]; then
+ . ./common/gcov
+ _gcov_check_report_gcov
+fi
+
_wrapup()
{
seq="check"
@@ -527,6 +532,18 @@ _wrapup()
"${#bad[*]}" "${#notrun[*]}" \
"$((sect_stop - sect_start))"
fi
+
+ # Generate code coverage report
+ if [ -n "$REPORT_GCOV" ]; then
+ # don't trigger multiple times if caller hits ^C
+ local gcov_report_dir="$REPORT_GCOV"
+ test "$gcov_report_dir" = "1" && \
+ gcov_report_dir="$REPORT_DIR/gcov"
+ unset REPORT_GCOV
+
+ _gcov_generate_report "$gcov_report_dir"
+ fi
+
needwrap=false
fi
@@ -801,6 +818,7 @@ function run_section()
echo "MOUNT_OPTIONS -- `_scratch_mount_options`"
fi
echo
+ test -n "$REPORT_GCOV" && _gcov_reset
needwrap=true
if [ ! -z "$SCRATCH_DEV" ]; then
diff --git a/common/gcov b/common/gcov
new file mode 100644
index 0000000000..b7e3ed5a93
--- /dev/null
+++ b/common/gcov
@@ -0,0 +1,87 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2023 Oracle. All Rights Reserved.
+#
+# Routines for capturing kernel code coverage reports
+
+GCOV_DIR=/sys/kernel/debug/gcov
+
+# Find the topmost directories of the .gcno directory hierarchy
+__gcov_find_topdirs() {
+ find "${GCOV_DIR}/" -name '*.gcno' -printf '%d|%h\n' | \
+ sort -g -k 1 | \
+ uniq | \
+ $AWK_PROG -F '|' 'BEGIN { x = -1 } { if (x < 0) x = $1; if ($1 == x) printf("%s\n", $2);}'
+}
+
+# Generate lcov html report from kernel gcov data if configured
+_gcov_generate_report() {
+ local output_dir="$1"
+ test -n "${output_dir}" || return
+
+ # Kernel support built in?
+ test -d "$GCOV_DIR" || return
+
+ readarray -t gcno_dirs < <(__gcov_find_topdirs)
+ test "${#gcno_dirs[@]}" -gt 0 || return
+
+ mkdir -p "${output_dir}/raw/"
+
+ # Collect raw coverage data from the kernel
+ readarray -t source_dirs < <(find "${GCOV_DIR}/" -mindepth 1 -maxdepth 1 -type d)
+ for dir in "${source_dirs[@]}"; do
+ cp -p -R -d -u "${dir}" "${output_dir}/raw/"
+ done
+
+ # If lcov is installed, use it to summarize the gcda data.
+ # If it is not installed, there's no point in going forward
+ command -v lcov > /dev/null || return
+ local lcov=(lcov --exclude 'include*' --capture)
+ lcov+=(--output-file "${output_dir}/gcov.report")
+ for d in "${gcno_dirs[@]}"; do
+ lcov+=(--directory "${d}")
+ done
+
+ # Generate a detailed HTML report from the summary
+ local gcov_start_time="$(date --date="${fstests_start_time:-now}")"
+ local genhtml=()
+ if command -v genhtml > /dev/null; then
+ genhtml+=(genhtml -o "${output_dir}/" "${output_dir}/gcov.report")
+ genhtml+=(--title "fstests on $(hostname -s) @ ${gcov_start_time}" --legend)
+ fi
+
+ # Try to convert the HTML report summary as text for easier grepping if
+ # there's an HTML renderer present
+ local totext=()
+ test "${#totext[@]}" -eq 0 && \
+ command -v lynx &>/dev/null && \
+ totext=(lynx -dump "${output_dir}/index.html" -width 120 -nonumbers -nolist)
+ test "${#totext[@]}" -eq 0 && \
+ command -v links &>/dev/null && \
+ totext=(links -dump "${output_dir}/index.html" -width 120)
+ test "${#totext[@]}" -eq 0 && \
+ command -v elinks &>/dev/null && \
+ totext=(elinks -dump "${output_dir}/index.html" --dump-width 120 --no-numbering --no-references)
+
+ # Analyze kernel data
+ "${lcov[@]}" > "${output_dir}/gcov.stdout" 2> "${output_dir}/gcov.stderr"
+ test "${#genhtml[@]}" -ne 0 && \
+ "${genhtml[@]}" >> "${output_dir}/gcov.stdout" 2>> "${output_dir}/gcov.stderr"
+ test "${#totext[@]}" -ne 0 && \
+ "${totext[@]}" > "${output_dir}/index.txt" 2>> "${output_dir}/gcov.stderr"
+}
+
+# Reset gcov usage data
+_gcov_reset() {
+ echo 1 > "${GCOV_DIR}/reset"
+}
+
+# If the caller wanted us to capture gcov reports but the kernel doesn't
+# support it, turn it off.
+_gcov_check_report_gcov() {
+ test -z "$REPORT_GCOV" && return 0
+ test -w "${GCOV_DIR}/reset" && return 0
+
+ unset REPORT_GCOV
+ return 1
+}
