[Devel] [PATCH vz10 v2 1/2] selftests: pstore: skip when no backend is registered

[Eva Kurchatova]

An unregistered pstore backend reads back "(null)", and every latter
check fails. This also contradicts the pstore_crash_test documentation.

Fix by skipping an unregistered backend in common_tests

https://virtuozzo.atlassian.net/browse/VSTOR-142447
Feature: fix selftests

Signed-off-by: Eva Kurchatova <eva.kurchatova at virtuozzo.com>
---
 tools/testing/selftests/pstore/common_tests       | 15 +++++++++++++--
 .../selftests/pstore/pstore_post_reboot_tests     |  2 --
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/pstore/common_tests b/tools/testing/selftests/pstore/common_tests
index 4509f0cc9c91..71cd4473f45a 100755
--- a/tools/testing/selftests/pstore/common_tests
+++ b/tools/testing/selftests/pstore/common_tests
@@ -55,6 +55,8 @@ operate_files() { # tested value, files, operation
 
 # Parameters
 TEST_STRING_PATTERN="Testing pstore: uuid="
+# Kselftest framework requirement - SKIP code is 4.
+ksft_skip=4
 UUID=`cat /proc/sys/kernel/random/uuid`
 TOP_DIR=`absdir $0`
 LOG_DIR=$TOP_DIR/logs/`date +%Y%m%d-%H%M%S`_${UUID}/
@@ -74,8 +76,17 @@ prlog "=== Pstore unit tests (`basename $0`) ==="
 prlog "UUID="$UUID
 
 prlog -n "Checking pstore backend is registered ... "
-backend=`cat /sys/module/pstore/parameters/backend`
-show_result $?
+# A tristate pstore leaves no parameter file at all when it is not built
+# or not loaded, and an unregistered backend reads back as "(null)".
+backend=`cat /sys/module/pstore/parameters/backend 2>/dev/null`
+if [ -z "$backend" ] || [ "$backend" = "(null)" ]; then
+    prlog "SKIP"
+    prlog -e "\tbackend=${backend:-<none>}"
+    prlog -e "\tcmdline=`cat /proc/cmdline`"
+    prlog "pstore backend is not registered, skipping"
+    exit $ksft_skip
+fi
+show_result 0
 prlog -e "\tbackend=${backend}"
 prlog -e "\tcmdline=`cat /proc/cmdline`"
 if [ $rc -ne 0 ]; then
diff --git a/tools/testing/selftests/pstore/pstore_post_reboot_tests b/tools/testing/selftests/pstore/pstore_post_reboot_tests
index d6da5e86efbf..a5464407f5b2 100755
--- a/tools/testing/selftests/pstore/pstore_post_reboot_tests
+++ b/tools/testing/selftests/pstore/pstore_post_reboot_tests
@@ -7,8 +7,6 @@
 #  Written by Hiraku Toyooka <hiraku.toyooka.gu at hitachi.com>
 #
 
-# Kselftest framework requirement - SKIP code is 4.
-ksft_skip=4
 
 . ./common_tests
 
-- 
2.55.0