[PATCH v2 4/6] selftests: livepatch: Check if patched sysfs attribute exists

[Marcos Paulo de Souza]

In order to run the selftests on older kernels, check if given kernel
has support for the attribute. If the attribute is not supported, skip
the checks.

Signed-off-by: Marcos Paulo de Souza <mpdesouza@xxxxxxxx>
---
 tools/testing/selftests/livepatch/test-sysfs.sh | 38 +++++++++++++++----------
 1 file changed, 23 insertions(+), 15 deletions(-)

diff --git a/tools/testing/selftests/livepatch/test-sysfs.sh b/tools/testing/selftests/livepatch/test-sysfs.sh
index 58fe1d96997c..a2d649404a63 100755
--- a/tools/testing/selftests/livepatch/test-sysfs.sh
+++ b/tools/testing/selftests/livepatch/test-sysfs.sh
@@ -8,6 +8,8 @@ MOD_LIVEPATCH=test_klp_livepatch
 MOD_LIVEPATCH2=test_klp_callbacks_demo
 MOD_LIVEPATCH3=test_klp_syscall
 
+HAS_PATCH_ATTR=0
+
 setup_config
 
 # - load a livepatch and verifies the sysfs entries work as expected
@@ -25,8 +27,12 @@ check_sysfs_rights "$MOD_LIVEPATCH" "stack_order" "-r--r--r--"
 check_sysfs_value  "$MOD_LIVEPATCH" "stack_order" "1"
 check_sysfs_rights "$MOD_LIVEPATCH" "transition" "-r--r--r--"
 check_sysfs_value  "$MOD_LIVEPATCH" "transition" "0"
-check_sysfs_rights "$MOD_LIVEPATCH" "vmlinux/patched" "-r--r--r--"
-check_sysfs_value  "$MOD_LIVEPATCH" "vmlinux/patched" "1"
+
+if does_sysfs_exists "$MOD_LIVEPATCH/vmlinux" "patched"; then
+	check_sysfs_rights "$MOD_LIVEPATCH" "vmlinux/patched" "-r--r--r--"
+	check_sysfs_value  "$MOD_LIVEPATCH" "vmlinux/patched" "1"
+	HAS_PATCH_ATTR=1
+fi
 
 disable_lp $MOD_LIVEPATCH
 
@@ -45,23 +51,24 @@ livepatch: '$MOD_LIVEPATCH': completing unpatching transition
 livepatch: '$MOD_LIVEPATCH': unpatching complete
 % rmmod $MOD_LIVEPATCH"
 
-start_test "sysfs test object/patched"
+if [[ "$HAS_PATCH_ATTR" == "1" ]]; then
+	start_test "sysfs test object/patched"
 
-MOD_LIVEPATCH=test_klp_callbacks_demo
-MOD_TARGET=test_klp_callbacks_mod
-load_lp $MOD_LIVEPATCH
+	MOD_LIVEPATCH=test_klp_callbacks_demo
+	MOD_TARGET=test_klp_callbacks_mod
+	load_lp $MOD_LIVEPATCH
 
-# check the "patch" file changes as target module loads/unloads
-check_sysfs_value  "$MOD_LIVEPATCH" "$MOD_TARGET/patched" "0"
-load_mod $MOD_TARGET
-check_sysfs_value  "$MOD_LIVEPATCH" "$MOD_TARGET/patched" "1"
-unload_mod $MOD_TARGET
-check_sysfs_value  "$MOD_LIVEPATCH" "$MOD_TARGET/patched" "0"
+	# check the "patch" file changes as target module loads/unloads
+	check_sysfs_value  "$MOD_LIVEPATCH" "$MOD_TARGET/patched" "0"
+	load_mod $MOD_TARGET
+	check_sysfs_value  "$MOD_LIVEPATCH" "$MOD_TARGET/patched" "1"
+	unload_mod $MOD_TARGET
+	check_sysfs_value  "$MOD_LIVEPATCH" "$MOD_TARGET/patched" "0"
 
-disable_lp $MOD_LIVEPATCH
-unload_lp $MOD_LIVEPATCH
+	disable_lp $MOD_LIVEPATCH
+	unload_lp $MOD_LIVEPATCH
 
-check_result "% insmod test_modules/test_klp_callbacks_demo.ko
+	check_result "% insmod test_modules/test_klp_callbacks_demo.ko
 livepatch: enabling patch 'test_klp_callbacks_demo'
 livepatch: 'test_klp_callbacks_demo': initializing patching transition
 test_klp_callbacks_demo: pre_patch_callback: vmlinux
@@ -87,6 +94,7 @@ livepatch: 'test_klp_callbacks_demo': completing unpatching transition
 test_klp_callbacks_demo: post_unpatch_callback: vmlinux
 livepatch: 'test_klp_callbacks_demo': unpatching complete
 % rmmod test_klp_callbacks_demo"
+fi
 
 start_test "sysfs test replace enabled"
 

-- 
2.52.0