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Posted to dev@tomcat.apache.org by ma...@apache.org on 2022/05/18 18:52:12 UTC

[tomcat] branch main updated: The ObjectStreamClass memory leak has been fixed in newer JREs

This is an automated email from the ASF dual-hosted git repository.

markt pushed a commit to branch main
in repository https://gitbox.apache.org/repos/asf/tomcat.git


The following commit(s) were added to refs/heads/main by this push:
     new 93108de112 The ObjectStreamClass memory leak has been fixed in newer JREs
93108de112 is described below

commit 93108de1127fb228e343a3f3304554bfe7177583
Author: Mark Thomas <ma...@apache.org>
AuthorDate: Wed May 18 19:52:00 2022 +0100

    The ObjectStreamClass memory leak has been fixed in newer JREs
    
    https://bugs.openjdk.java.net/browse/JDK-8277072
    Disable the clean-up code when running on a JRE that includes the fix.
---
 .../catalina/loader/WebappClassLoaderBase.java     | 27 +++++++++++++++-------
 webapps/docs/changelog.xml                         |  5 ++++
 webapps/docs/config/context.xml                    |  4 ++++
 3 files changed, 28 insertions(+), 8 deletions(-)

diff --git a/java/org/apache/catalina/loader/WebappClassLoaderBase.java b/java/org/apache/catalina/loader/WebappClassLoaderBase.java
index b87cc72abe..6ba682b610 100644
--- a/java/org/apache/catalina/loader/WebappClassLoaderBase.java
+++ b/java/org/apache/catalina/loader/WebappClassLoaderBase.java
@@ -2289,6 +2289,12 @@ public abstract class WebappClassLoaderBase extends URLClassLoader
 
 
     private void clearReferencesObjectStreamClassCaches() {
+        if (JreCompat.isJre19Available()) {
+            // The memory leak this fixes has been fixed in Java 19 onwards,
+            // 17.0.4 onwards and 11.0.16 onwards
+            // See https://bugs.openjdk.java.net/browse/JDK-8277072
+            return;
+        }
         try {
             Class<?> clazz = Class.forName("java.io.ObjectStreamClass$Caches");
             clearCache(clazz, "localDescs");
@@ -2316,14 +2322,19 @@ public abstract class WebappClassLoaderBase extends URLClassLoader
             throws ReflectiveOperationException, SecurityException, ClassCastException {
         Field f = target.getDeclaredField(mapName);
         f.setAccessible(true);
-        Map<?,?> map = (Map<?,?>) f.get(null);
-        Iterator<?> keys = map.keySet().iterator();
-        while (keys.hasNext()) {
-            Object key = keys.next();
-            if (key instanceof Reference) {
-                Object clazz = ((Reference<?>) key).get();
-                if (loadedByThisOrChild(clazz)) {
-                    keys.remove();
+        Object map = f.get(null);
+        // Avoid trying to clear references if Tomcat is running on a JRE that
+        // includes the fix for this memory leak
+        // See https://bugs.openjdk.java.net/browse/JDK-8277072
+        if (map instanceof Map<?,?>) {
+            Iterator<?> keys = ((Map<?,?>) map).keySet().iterator();
+            while (keys.hasNext()) {
+                Object key = keys.next();
+                if (key instanceof Reference) {
+                    Object clazz = ((Reference<?>) key).get();
+                    if (loadedByThisOrChild(clazz)) {
+                        keys.remove();
+                    }
                 }
             }
         }
diff --git a/webapps/docs/changelog.xml b/webapps/docs/changelog.xml
index 2b22817b79..c1a182402b 100644
--- a/webapps/docs/changelog.xml
+++ b/webapps/docs/changelog.xml
@@ -115,6 +115,11 @@
         Improve the error message if a required <code>--add-opens</code> option
         is missing. (markt)
       </fix>
+      <fix>
+        Disable the memory leak correction code enabled by the Context attribute
+        <code>clearReferencesObjectStreamClassCaches</code> when running on a
+        JRE that includes a fix for the underlying memory leak. (markt)
+      </fix>
     </changelog>
   </subsection>
   <subsection name="Jasper">
diff --git a/webapps/docs/config/context.xml b/webapps/docs/config/context.xml
index 78e75b20d8..0fa30a07f2 100644
--- a/webapps/docs/config/context.xml
+++ b/webapps/docs/config/context.xml
@@ -799,6 +799,10 @@
         therefore requires that the command line option
         <code>-XaddExports:java.base/java.io=ALL-UNNAMED</code> is set. If not
         specified, the default value of <code>true</code> will be used.</p>
+        <p>The memory leak associated with <code>ObjectStreamClass</code> has
+        been fixed in Java 19 onwards, Java 17.0.4 onwards and Java 11.0.16
+        onwards. The check will be disabled when running on a version
+        of Java that contains the fix.</p>
       </attribute>
 
       <attribute name="clearReferencesRmiTargets" required="false">


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Re: [tomcat] branch main updated: The ObjectStreamClass memory leak has been fixed in newer JREs

Posted by Rémy Maucherat <re...@apache.org>.
On Wed, May 18, 2022 at 8:52 PM <ma...@apache.org> wrote:
>
> This is an automated email from the ASF dual-hosted git repository.
>
> markt pushed a commit to branch main
> in repository https://gitbox.apache.org/repos/asf/tomcat.git
>
>
> The following commit(s) were added to refs/heads/main by this push:
>      new 93108de112 The ObjectStreamClass memory leak has been fixed in newer JREs
> 93108de112 is described below
>
> commit 93108de1127fb228e343a3f3304554bfe7177583
> Author: Mark Thomas <ma...@apache.org>
> AuthorDate: Wed May 18 19:52:00 2022 +0100
>
>     The ObjectStreamClass memory leak has been fixed in newer JREs
>
>     https://bugs.openjdk.java.net/browse/JDK-8277072
>     Disable the clean-up code when running on a JRE that includes the fix.

This is great because accessing the structures to clean them up looked
hard to me (I couldn't understand how this cache worked today ;) ).

Rémy

> ---
>  .../catalina/loader/WebappClassLoaderBase.java     | 27 +++++++++++++++-------
>  webapps/docs/changelog.xml                         |  5 ++++
>  webapps/docs/config/context.xml                    |  4 ++++
>  3 files changed, 28 insertions(+), 8 deletions(-)
>
> diff --git a/java/org/apache/catalina/loader/WebappClassLoaderBase.java b/java/org/apache/catalina/loader/WebappClassLoaderBase.java
> index b87cc72abe..6ba682b610 100644
> --- a/java/org/apache/catalina/loader/WebappClassLoaderBase.java
> +++ b/java/org/apache/catalina/loader/WebappClassLoaderBase.java
> @@ -2289,6 +2289,12 @@ public abstract class WebappClassLoaderBase extends URLClassLoader
>
>
>      private void clearReferencesObjectStreamClassCaches() {
> +        if (JreCompat.isJre19Available()) {
> +            // The memory leak this fixes has been fixed in Java 19 onwards,
> +            // 17.0.4 onwards and 11.0.16 onwards
> +            // See https://bugs.openjdk.java.net/browse/JDK-8277072
> +            return;
> +        }
>          try {
>              Class<?> clazz = Class.forName("java.io.ObjectStreamClass$Caches");
>              clearCache(clazz, "localDescs");
> @@ -2316,14 +2322,19 @@ public abstract class WebappClassLoaderBase extends URLClassLoader
>              throws ReflectiveOperationException, SecurityException, ClassCastException {
>          Field f = target.getDeclaredField(mapName);
>          f.setAccessible(true);
> -        Map<?,?> map = (Map<?,?>) f.get(null);
> -        Iterator<?> keys = map.keySet().iterator();
> -        while (keys.hasNext()) {
> -            Object key = keys.next();
> -            if (key instanceof Reference) {
> -                Object clazz = ((Reference<?>) key).get();
> -                if (loadedByThisOrChild(clazz)) {
> -                    keys.remove();
> +        Object map = f.get(null);
> +        // Avoid trying to clear references if Tomcat is running on a JRE that
> +        // includes the fix for this memory leak
> +        // See https://bugs.openjdk.java.net/browse/JDK-8277072
> +        if (map instanceof Map<?,?>) {
> +            Iterator<?> keys = ((Map<?,?>) map).keySet().iterator();
> +            while (keys.hasNext()) {
> +                Object key = keys.next();
> +                if (key instanceof Reference) {
> +                    Object clazz = ((Reference<?>) key).get();
> +                    if (loadedByThisOrChild(clazz)) {
> +                        keys.remove();
> +                    }
>                  }
>              }
>          }
> diff --git a/webapps/docs/changelog.xml b/webapps/docs/changelog.xml
> index 2b22817b79..c1a182402b 100644
> --- a/webapps/docs/changelog.xml
> +++ b/webapps/docs/changelog.xml
> @@ -115,6 +115,11 @@
>          Improve the error message if a required <code>--add-opens</code> option
>          is missing. (markt)
>        </fix>
> +      <fix>
> +        Disable the memory leak correction code enabled by the Context attribute
> +        <code>clearReferencesObjectStreamClassCaches</code> when running on a
> +        JRE that includes a fix for the underlying memory leak. (markt)
> +      </fix>
>      </changelog>
>    </subsection>
>    <subsection name="Jasper">
> diff --git a/webapps/docs/config/context.xml b/webapps/docs/config/context.xml
> index 78e75b20d8..0fa30a07f2 100644
> --- a/webapps/docs/config/context.xml
> +++ b/webapps/docs/config/context.xml
> @@ -799,6 +799,10 @@
>          therefore requires that the command line option
>          <code>-XaddExports:java.base/java.io=ALL-UNNAMED</code> is set. If not
>          specified, the default value of <code>true</code> will be used.</p>
> +        <p>The memory leak associated with <code>ObjectStreamClass</code> has
> +        been fixed in Java 19 onwards, Java 17.0.4 onwards and Java 11.0.16
> +        onwards. The check will be disabled when running on a version
> +        of Java that contains the fix.</p>
>        </attribute>
>
>        <attribute name="clearReferencesRmiTargets" required="false">
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: dev-unsubscribe@tomcat.apache.org
> For additional commands, e-mail: dev-help@tomcat.apache.org
>

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