[PATCH v9 16/52] selftests-dyndbg: add tools/testing/selftests/dynamic_debug/*

Jim Cromie
2024-07-02T21:58:34Z

Add a selftest script for dynamic-debug. The config requires
CONFIG_TEST_DYNAMIC_DEBUG=m (and CONFIG_TEST_DYNAMIC_DEBUG_SUBMOD=m),
which tacitly requires either CONFIG_DYNAMIC_DEBUG=y or
CONFIG_DYNAMIC_DEBUG_CORE=y

ATM this has just basic_tests(), it modifies pr_debug flags in a few
builtins (init/main, params), counts the callsite flags changed, and
verifies against expected values.

This is backported from another feature branch; the support-fns (thx
Lukas) have unused features at the moment, they'll get used shortly.

The script enables simple virtme-ng testing:

$> vng --verbose --name v6.8-32-g30d431000676 --user root \
--cwd ../.. -a dynamic_debug.verbose=2 -p 4 \
./tools/testing/selftests/dynamic_debug/dyndbg_selftest.sh

virtme: waiting for virtiofsd to start
virtme: use 'microvm' QEMU architecture
...
[ 4.136168] virtme-init: Setting hostname to v6.8-32-g30d431000676...
[ 4.240874] virtme-init: starting script
test_dynamic_debug_submod not there
test_dynamic_debug not there
...
[ 4.474435] virtme-init: script returned {0}
Powering off.
[ 4.529318] ACPI: PM: Preparing to enter system sleep state S5
[ 4.529991] kvm: exiting hardware virtualization
[ 4.530428] reboot: Power down

And add dynamic_debug to TARGETS, so `make run_tests` sees it properly

for the impatient, set TARGETS explicitly:

bash-5.2# make TARGETS=dynamic_debug run_tests
make[1]: ...
TAP version 13
1..1
[ 35.552922] dyndbg: read 3 bytes from userspace
[ 35.553099] dyndbg: query 0: "=_" mod:*
[ 35.553544] dyndbg: processed 1 queries, with 1778 matches, 0 errs
...

TLDR:

This selftest is slightly naive wrt the init state of call-site flags.

In particular, it fails if class'd pr_debugs have been set

$ cat /etc/modprobe.d/drm-test.conf
options drm dyndbg=class,DRM_UT_CORE,+mfslt%class,DRM_UT_KMS,+mf

By Contract, class'd pr_debugs are protected from alteration by
default (only by direct "class FOO" queries), so the "=_" logged above
(TAP version 13) cannot affect the DRM_UT_CORE,KMS pr_debugs.

These class'd flag-settings, added by modprobe, alter the counts of
flag-matching patterns, breaking the tests' expectations.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Co-developed-by: Łukasz Bartosik <ukaszb@chromium.org>
Signed-off-by: Łukasz Bartosik <ukaszb@chromium.org>
---
MAINTAINERS | 1 +
tools/testing/selftests/Makefile | 1 +
.../testing/selftests/dynamic_debug/Makefile | 9 +
tools/testing/selftests/dynamic_debug/config | 2 +
.../dynamic_debug/dyndbg_selftest.sh | 231 ++++++++++++++++++
5 files changed, 244 insertions(+)
create mode 100644 tools/testing/selftests/dynamic_debug/Makefile
create mode 100644 tools/testing/selftests/dynamic_debug/config
create mode 100755 tools/testing/selftests/dynamic_debug/dyndbg_selftest.sh

diff --git a/MAINTAINERS b/MAINTAINERS
index c9ed48109ff5..e7bb7b1c44c8 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -7527,6 +7527,7 @@ S: Maintained
F: include/linux/dynamic_debug.h
F: lib/dynamic_debug.c
F: lib/test_dynamic_debug*.c
+F: tools/testing/selftest/dynamic_debug/*

DYNAMIC INTERRUPT MODERATION
M: Tal Gilboa <talgi@nvidia.com>
diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index e1504833654d..84edf0bd8e80 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -20,6 +20,7 @@ TARGETS += drivers/s390x/uvdevice
TARGETS += drivers/net/bonding
TARGETS += drivers/net/team
TARGETS += dt
+TARGETS += dynamic_debug
TARGETS += efivarfs
TARGETS += exec
TARGETS += fchmodat2
diff --git a/tools/testing/selftests/dynamic_debug/Makefile b/tools/testing/selftests/dynamic_debug/Makefile
new file mode 100644
index 000000000000..6d06fa7f1040
--- /dev/null
+++ b/tools/testing/selftests/dynamic_debug/Makefile
@@ -0,0 +1,9 @@
+# SPDX-License-Identifier: GPL-2.0-only
+# borrowed from Makefile for user memory selftests
+
+# No binaries, but make sure arg-less "make" doesn't trigger "run_tests"
+all:
+
+TEST_PROGS := dyndbg_selftest.sh
+
+include ../lib.mk
diff --git a/tools/testing/selftests/dynamic_debug/config b/tools/testing/selftests/dynamic_debug/config
new file mode 100644
index 000000000000..d080da571ac0
--- /dev/null
+++ b/tools/testing/selftests/dynamic_debug/config
@@ -0,0 +1,2 @@
+CONFIG_TEST_DYNAMIC_DEBUG=m
+CONFIG_TEST_DYNAMIC_DEBUG_SUBMOD=m
diff --git a/tools/testing/selftests/dynamic_debug/dyndbg_selftest.sh b/tools/testing/selftests/dynamic_debug/dyndbg_selftest.sh
new file mode 100755
index 000000000000..1be70af26a38
--- /dev/null
+++ b/tools/testing/selftests/dynamic_debug/dyndbg_selftest.sh
@@ -0,0 +1,231 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0-only
+
+V=${V:=0} # invoke as V=1 $0 for global verbose
+RED="\033[0;31m"
+GREEN="\033[0;32m"
+YELLOW="\033[0;33m"
+BLUE="\033[0;34m"
+MAGENTA="\033[0;35m"
+CYAN="\033[0;36m"
+NC="\033[0;0m"
+error_msg=""
+
+function vx () {
+ echo $1 > /sys/module/dynamic_debug/parameters/verbose
+}
+
+function ddgrep () {
+ grep $1 /proc/dynamic_debug/control
+}
+
+function doprints () {
+ cat /sys/module/test_dynamic_debug/parameters/do_prints
+}
+
+function ddcmd () {
+ exp_exit_code=0
+ num_args=$#
+ if [ "${@:$#}" = "pass" ]; then
+ num_args=$#-1
+ elif [ "${@:$#}" = "fail" ]; then
+ num_args=$#-1
+ exp_exit_code=1
+ fi
+ args=${@:1:$num_args}
+ output=$((echo "$args" > /proc/dynamic_debug/control) 2>&1)
+ exit_code=$?
+ error_msg=$(echo $output | cut -d ":" -f 5 | sed -e 's/^[[:space:]]*//')
+ handle_exit_code $BASH_LINENO $FUNCNAME $exit_code $exp_exit_code
+}
+
+function handle_exit_code() {
+ local exp_exit_code=0
+ [ $# == 4 ] && exp_exit_code=$4
+ if [ $3 -ne $exp_exit_code ]; then
+ echo -e "${RED}: $BASH_SOURCE:$1 $2() expected to exit with code $exp_exit_code"
+ [ $3 == 1 ] && echo "Error: '$error_msg'"
+ exit
+ fi
+}
+
+# $1 - pattern to match, pattern in $1 is enclosed by spaces for a match ""\s$1\s"
+# $2 - number of times the pattern passed in $1 is expected to match
+# $3 - optional can be set either to "-r" or "-v"
+# "-r" means relaxed matching in this case pattern provided in $1 is passed
+# as is without enclosing it with spaces
+# "-v" prints matching lines
+# $4 - optional when $3 is set to "-r" then $4 can be used to pass "-v"
+function check_match_ct {
+ pattern="\s$1\s"
+ exp_cnt=0
+
+ [ "$3" == "-r" ] && pattern="$1"
+ let cnt=$(ddgrep "$pattern" | wc -l)
+ if [ $V -eq 1 ] || [ "$3" == "-v" ] || [ "$4" == "-v" ]; then
+ echo -ne "${BLUE}" && ddgrep $pattern && echo -ne "${NC}"
+ fi
+ [ $# -gt 1 ] && exp_cnt=$2
+ if [ $cnt -ne $exp_cnt ]; then
+ echo -e "${RED}: $BASH_SOURCE:$BASH_LINENO check failed expected $exp_cnt on $1, got $cnt"
+ exit
+ else
+ echo ": $cnt matches on $1"
+ fi
+}
+
+# $1 - trace instance name
+# #2 - if > 0 then directory is expected to exist, if <= 0 then otherwise
+# $3 - "-v" for verbose
+function check_trace_instance_dir {
+ if [ -e /sys/kernel/tracing/instances/$1 ]; then
+ if [ "$3" == "-v" ] ; then
+ echo "ls -l /sys/kernel/tracing/instances/$1: "
+ ls -l /sys/kernel/tracing/instances/$1
+ fi
+ if [ $2 -le 0 ]; then
+ echo -e "${RED}: $BASH_SOURCE:$BASH_LINENO error trace instance \
+ '/sys/kernel/tracing/instances/$1' does exist"
+ exit
+ fi
+ else
+ if [ $2 -gt 0 ]; then
+ echo -e "${RED}: $BASH_SOURCE:$BASH_LINENO error trace instance \
+ '/sys/kernel/tracing/instances/$1' does not exist"
+ exit
+ fi
+ fi
+}
+
+function tmark {
+ echo $* > /sys/kernel/tracing/trace_marker
+}
+
+# $1 - trace instance name
+# $2 - line number
+# $3 - if > 0 then the instance is expected to be opened, otherwise
+# the instance is expected to be closed
+function check_trace_instance {
+ output=$(tail -n9 /proc/dynamic_debug/control | grep ": Opened trace instances" \
+ | xargs -n1 | grep $1)
+ if [ "$output" != $1 ] && [ $3 -gt 0 ]; then
+ echo -e "${RED}: $BASH_SOURCE:$2 trace instance $1 is not opened"
+ exit
+ fi
+ if [ "$output" == $1 ] && [ $3 -le 0 ]; then
+ echo -e "${RED}: $BASH_SOURCE:$2 trace instance $1 is not closed"
+ exit
+ fi
+}
+
+function is_trace_instance_opened {
+ check_trace_instance $1 $BASH_LINENO 1
+}
+
+function is_trace_instance_closed {
+ check_trace_instance $1 $BASH_LINENO 0
+}
+
+# $1 - trace instance directory to delete
+# $2 - if > 0 then directory is expected to be deleted successfully, if <= 0 then otherwise
+function del_trace_instance_dir() {
+ exp_exit_code=1
+ [ $2 -gt 0 ] && exp_exit_code=0
+ output=$((rmdir /sys/kernel/debug/tracing/instances/$1) 2>&1)
+ exit_code=$?
+ error_msg=$(echo $output | cut -d ":" -f 3 | sed -e 's/^[[:space:]]*//')
+ handle_exit_code $BASH_LINENO $FUNCNAME $exit_code $exp_exit_code
+}
+
+function error_log_ref {
+ # to show what I got
+ : echo "# error-log-ref: $1"
+ : echo cat \$2
+}
+
+function ifrmmod {
+ lsmod | grep $1 2>&1>/dev/null || echo $1 not there
+ lsmod | grep $1 2>&1>/dev/null && rmmod $1
+}
+
+# $1 - text to search for
+function search_trace() {
+ search_trace_name 0 1 $1
+}
+
+# $1 - trace instance name, 0 for global event trace
+# $2 - line number counting from the bottom
+# $3 - text to search for
+function search_trace_name() {
+ if [ "$1" = "0" ]; then
+ buf=$(cat /sys/kernel/debug/tracing/trace)
+ line=$(tail -$2 /sys/kernel/debug/tracing/trace | head -1 | sed -e 's/^[[:space:]]*//')
+ else
+ buf=$(cat /sys/kernel/debug/tracing/instances/$1/trace)
+ line=$(tail -$2 /sys/kernel/debug/tracing/instances/$1/trace | head -1 | \
+ sed -e 's/^[[:space:]]*//')
+ fi
+ if [ $2 = 0 ]; then
+ # whole-buf check
+ output=$(echo $buf | grep "$3")
+ else
+ output=$(echo $line | grep "$3")
+ fi
+ if [ "$output" = "" ]; then
+ echo -e "${RED}: $BASH_SOURCE:$BASH_LINENO search for '$3' failed \
+ in line '$line' or '$buf'"
+ exit
+ fi
+ if [ $V = 1 ]; then
+ echo -e "${MAGENTA}: search_trace_name in $1 found: \n$output \nin:${BLUE} $buf ${NC}"
+ fi
+}
+
+# $1 - error message to check
+function check_err_msg() {
+ if [ "$error_msg" != "$1" ]; then
+ echo -e "${RED}: $BASH_SOURCE:$BASH_LINENO error message '$error_msg' \
+ does not match with '$1'"
+ exit
+ fi
+}
+
+function basic_tests {
+ echo -e "${GREEN}# BASIC_TESTS ${NC}"
+ ddcmd =_ # zero everything (except class'd sites)
+ check_match_ct =p 0
+ # there are several main's :-/
+ ddcmd module main file */module/main.c +p
+ check_match_ct =p 14
+ ddcmd =_
+ check_match_ct =p 0
+ # multi-cmd input, newline separated, with embedded comments
+ cat <<"EOF" > /proc/dynamic_debug/control
+ module main +mf # multi-query
+ module main file init/main.c +ml # newline separated
+EOF
+ # the intersection of all those main's is hard to track/count
+ # esp when mixed with overlapping greps
+ check_match_ct =mf 21
+ check_match_ct =ml 0
+ check_match_ct =mfl 6
+ ddcmd =_
+}
+
+
+tests_list=(
+ basic_tests
+)
+
+# Run tests
+
+ifrmmod test_dynamic_debug_submod
+ifrmmod test_dynamic_debug
+
+for test in "${tests_list[@]}"
+do
+ $test
+ echo ""
+done
+echo -en "${GREEN}# Done on: "
+date
--
2.45.2