Re: [PATCH v2 6/6] selftests: livepatch: Test livepatching function using an external symbol

[Petr Mladek]

On Thu 2024-05-16 15:30:09, Lukas Hruska wrote:
> The test proves that klp-convert works as intended and it is possible to
> livepatch a function that use an external symbol.
> 
> Signed-off-by: Lukas Hruska 

> --- a/tools/testing/selftests/livepatch/functions.sh
> +++ b/tools/testing/selftests/livepatch/functions.sh
> @@ -7,6 +7,7 @@
>  MAX_RETRIES=600
>  RETRY_INTERVAL=".1"  # seconds
>  KLP_SYSFS_DIR="/sys/kernel/livepatch"
> +MODULE_SYSFS_DIR="/sys/module"
>  
>  # Kselftest framework requirement - SKIP code is 4
>  ksft_skip=4
> @@ -299,7 +300,7 @@ function check_result {
>   result=$(dmesg | awk -v last_dmesg="$LAST_DMESG" 'p; $0 == last_dmesg { 
> p=1 }' | \
>grep -e 'livepatch:' -e 'test_klp' | \
>grep -v '\(tainting\|taints\) kernel' | \
> -  sed 's/^\[[ 0-9.]*\] //')
> +  sed 's/^\[[ 0-9.]*\] //' | sed 's/^test_klp_log: //')

The prefix "test_klp_log:" is not used anywhere. It seems that this
change is not needed in the final version.

>  
>   if [[ "$expect" == "$result" ]] ; then
>   echo "ok"

Otherwise, it looks and works nice. With the hunk removed:

Reviewed-by: Petr Mladek 
Tested-by: Petr Mladek 

Best Regards,
Petr

[PATCH v2 6/6] selftests: livepatch: Test livepatching function using an external symbol

[Lukas Hruska]

The test proves that klp-convert works as intended and it is possible to
livepatch a function that use an external symbol.

Signed-off-by: Lukas Hruska 
---
 .../testing/selftests/livepatch/functions.sh  | 16 +-
 .../selftests/livepatch/test-extern.sh| 57 +++
 .../selftests/livepatch/test_modules/Makefile |  2 +
 .../livepatch/test_modules/test_klp_extern.c  | 51 +
 .../test_modules/test_klp_extern_hello.c  | 36 
 5 files changed, 161 insertions(+), 1 deletion(-)
 create mode 100755 tools/testing/selftests/livepatch/test-extern.sh
 create mode 100644 
tools/testing/selftests/livepatch/test_modules/test_klp_extern.c
 create mode 100644 
tools/testing/selftests/livepatch/test_modules/test_klp_extern_hello.c

diff --git a/tools/testing/selftests/livepatch/functions.sh 
b/tools/testing/selftests/livepatch/functions.sh
index fc4c6a016d38..801d55dc06ac 100644
--- a/tools/testing/selftests/livepatch/functions.sh
+++ b/tools/testing/selftests/livepatch/functions.sh
@@ -7,6 +7,7 @@
 MAX_RETRIES=600
 RETRY_INTERVAL=".1"# seconds
 KLP_SYSFS_DIR="/sys/kernel/livepatch"
+MODULE_SYSFS_DIR="/sys/module"
 
 # Kselftest framework requirement - SKIP code is 4
 ksft_skip=4
@@ -299,7 +300,7 @@ function check_result {
result=$(dmesg | awk -v last_dmesg="$LAST_DMESG" 'p; $0 == last_dmesg { 
p=1 }' | \
 grep -e 'livepatch:' -e 'test_klp' | \
 grep -v '\(tainting\|taints\) kernel' | \
-sed 's/^\[[ 0-9.]*\] //')
+sed 's/^\[[ 0-9.]*\] //' | sed 's/^test_klp_log: //')
 
if [[ "$expect" == "$result" ]] ; then
echo "ok"
@@ -344,3 +345,16 @@ function check_sysfs_value() {
die "Unexpected value in $path: $expected_value vs. $value"
fi
 }
+
+# read_module_param_value(modname, param) - read module parameter value
+#  modname - livepatch module creating the sysfs interface
+#  param - parameter name
+function read_module_param() {
+   local mod="$1"; shift
+   local param="$1"; shift
+
+   local path="$MODULE_SYSFS_DIR/$mod/parameters/$param"
+
+   log "% echo \"$mod/parameters/$param: \$(cat $path)\""
+   log "$mod/parameters/$param: $(cat $path)"
+}
diff --git a/tools/testing/selftests/livepatch/test-extern.sh 
b/tools/testing/selftests/livepatch/test-extern.sh
new file mode 100755
index ..3dde6cabb07c
--- /dev/null
+++ b/tools/testing/selftests/livepatch/test-extern.sh
@@ -0,0 +1,57 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2024 Lukas Hruska 
+
+. $(dirname $0)/functions.sh
+
+MOD_LIVEPATCH=test_klp_extern
+MOD_HELLO=test_klp_extern_hello
+PARAM_HELLO=hello
+
+setup_config
+
+# - load a module to be livepatched
+# - load a livepatch that modifies the output from 'hello' parameter
+#   of the previously loaded module and verify correct behaviour
+# - unload the livepatch and make sure the patch was removed
+# - unload the module that was livepatched
+
+start_test "livepatch with external symbol"
+
+load_mod $MOD_HELLO
+
+read_module_param $MOD_HELLO $PARAM_HELLO
+
+load_lp $MOD_LIVEPATCH
+
+read_module_param $MOD_HELLO $PARAM_HELLO
+
+disable_lp $MOD_LIVEPATCH
+unload_lp $MOD_LIVEPATCH
+
+read_module_param $MOD_HELLO $PARAM_HELLO
+
+unload_mod $MOD_HELLO
+
+check_result "% insmod test_modules/$MOD_HELLO.ko
+% echo \"$MOD_HELLO/parameters/$PARAM_HELLO: \$(cat 
/sys/module/$MOD_HELLO/parameters/$PARAM_HELLO)\"
+$MOD_HELLO/parameters/$PARAM_HELLO: Hello from kernel module.
+% insmod test_modules/$MOD_LIVEPATCH.ko
+livepatch: enabling patch '$MOD_LIVEPATCH'
+livepatch: '$MOD_LIVEPATCH': initializing patching transition
+livepatch: '$MOD_LIVEPATCH': starting patching transition
+livepatch: '$MOD_LIVEPATCH': completing patching transition
+livepatch: '$MOD_LIVEPATCH': patching complete
+% echo \"$MOD_HELLO/parameters/$PARAM_HELLO: \$(cat 
/sys/module/$MOD_HELLO/parameters/$PARAM_HELLO)\"
+$MOD_HELLO/parameters/$PARAM_HELLO: Hello from livepatched module.
+% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH/enabled
+livepatch: '$MOD_LIVEPATCH': initializing unpatching transition
+livepatch: '$MOD_LIVEPATCH': starting unpatching transition
+livepatch: '$MOD_LIVEPATCH': completing unpatching transition
+livepatch: '$MOD_LIVEPATCH': unpatching complete
+% rmmod $MOD_LIVEPATCH
+% echo \"$MOD_HELLO/parameters/$PARAM_HELLO: \$(cat 
/sys/module/$MOD_HELLO/parameters/$PARAM_HELLO)\"
+$MOD_HELLO/parameters/$PARAM_HELLO: Hello from kernel module.
+% rmmod $MOD_HELLO"
+
+exit 0
diff --git a/tools/testing/selftests/livepatch/test_modules/Makefile 
b/tools/testing/selftests/livepatch/test_modules/Makefile
index e6e638c4bcba..0d6df14787da 100644
--- a/tools/testing/selftests/livepatch/test_modules/Makefile
+++ b/tools/testing/selftests/livepatch/test_modules/Makefile
@@ -6,6 +6,8 @@ obj-m += test_klp_atomic_replace.o \
test_klp_callbacks_demo.o \
test_klp_callbacks_demo2.o \
test_klp_callbacks_mod.o \
+   test_klp_e