Regression in EPollArrayWrapper causes NPE when fd > 64 * 1024

[Alan Bateman]

On 16/09/2013 21:02, Norman Maurer wrote:
> Hi Alan,
>
> for sure I want to contribute a patch. Seems like the patches / 
> reproducer are visible in the mail archive[1].
>
> Anyway here are the files included inline:
Attachments are usually stripped by the OpenJDK mail servers so I'm 
surprised they are there.

On the test case (or reproducer): as there is configuration required to 
allow >64k connections then a simpler way to demonstrate it is to 
initially consume 64k file descriptors (by opening files or create 
SocketChannels). That's what I did when I saw your mail in order to 
duplicate it quickly. We need to decide whether to attempt to include a 
test case with this patch. I'm in two minds on this as I don't know how 
often the test will be run in environments where the maximum number of 
file descriptors is unlimited or high enough. An alternative (for a 
future patch perhaps) is to make MAX_UPDATE_ARRAY_SIZE configurable so 
that the spilling can tested without requiring the maximum number of 
file descriptors to be increased.

Your patch is essentially the same as what I tested with yesterday. I've 
changed to the attached (to make it consistent with the eventsLow code 
mostly). If you are okay with this then I will push it listing you as 
contributor.

-Alan.


diff --git a/src/solaris/classes/sun/nio/ch/EPollArrayWrapper.java 
b/src/solaris/classes/sun/nio/ch/EPollArrayWrapper.java
--- a/src/solaris/classes/sun/nio/ch/EPollArrayWrapper.java
+++ b/src/solaris/classes/sun/nio/ch/EPollArrayWrapper.java
@@ -164,6 +164,16 @@
      }

      /**
+     * Returns {@code true} if updates for the given key (file
+     * descriptor) are killed.
+     */
+    private boolean isEventsHighKilled(Integer key) {
+        assert key >= MAX_UPDATE_ARRAY_SIZE;
+        Byte value = eventsHigh.get(key);
+        return (value != null && value == KILLED);
+    }
+
+    /**
       * Sets the pending update events for the given file descriptor. This
       * method has no effect if the update events is already set to KILLED,
       * unless {@code force} is {@code true}.
@@ -175,7 +185,7 @@
              }
          } else {
              Integer key = Integer.valueOf(fd);
-            if ((eventsHigh.get(key) != KILLED) || force) {
+            if (!isEventsHighKilled(key) || force) {
                  eventsHigh.put(key, Byte.valueOf(events));
              }
          }

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