8287073: NPE from CgroupV2Subsystem.getInstance()

Backport-of: 744b822ab194a0f7ef4e7a4053be32c6a0889efc
openjdk · Jun 13, 2022 · cb88133 · cb88133 · openjdk-notifier · Jun 13, 2022
1 parent 292d90d
commit cb88133
Showing 1 changed file with 4 additions and 3 deletions.
diff --git a/src/java.base/linux/classes/jdk/internal/platform/CgroupSubsystemFactory.java b/src/java.base/linux/classes/jdk/internal/platform/CgroupSubsystemFactory.java
@@ -36,6 +36,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
+import java.util.Objects;
 import java.util.function.Consumer;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
@@ -110,9 +111,9 @@ static CgroupMetrics create() {
         Map<String, CgroupInfo> infos = result.getInfos();
         if (result.isCgroupV2()) {
             // For unified it doesn't matter which controller we pick.
-            CgroupInfo anyController = infos.get(MEMORY_CTRL);
-            CgroupSubsystem subsystem = CgroupV2Subsystem.getInstance(anyController);
-            return subsystem != null ? new CgroupMetrics(subsystem) : null;
+            CgroupInfo anyController = infos.values().iterator().next();
+            CgroupSubsystem subsystem = CgroupV2Subsystem.getInstance(Objects.requireNonNull(anyController));
+            return new CgroupMetrics(subsystem);
         } else {
             CgroupV1Subsystem subsystem = CgroupV1Subsystem.getInstance(infos);
             return subsystem != null ? new CgroupV1MetricsImpl(subsystem) : null;