Bump org.apache.logging.log4j:log4j-core from 2.26.0 to 2.26.1

Bumps org.apache.logging.log4j:log4j-core from 2.26.0 to 2.26.1.

---
updated-dependencies:
- dependency-name: org.apache.logging.log4j:log4j-core
  dependency-version: 2.26.1
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

- Runner stop deadlock

- Runner.stop and run methods compete for the same intrinsic lock when
  stopping.

- Added RunnerTest.testStop2(): https://redhat.atlassian.net/browse/JGRP-3020

Author: dependabot[bot]

src/org/jgroups/util/Runner.java

@@ -61,11 +61,15 @@ public synchronized Runner start() {
         return this;
     }
 
-    public synchronized Runner stop() {
-        boolean rc=state(State.stopping);
-        if(!rc)
-            return this;
-        Thread tmp=thread;
+    public Runner stop() {
+        Thread tmp;
+        synchronized (this) {
+            boolean rc=state(State.stopping);
+            if(!rc)
+                return this;
+            tmp=thread;
+        }
+
         if(tmp != null) {
             tmp.interrupt();
             if(join_timeout > 0) {

tests/junit-functional/org/jgroups/tests/RunnerTest.java

@@ -81,6 +81,23 @@ public void testStop() throws TimeoutException {
         Util.waitUntil(5000, 100, () -> runner.state() == stopped);
     }
 
+    /** Tests https://redhat.atlassian.net/browse/JGRP-3020 */
+    public void testStop2() throws TimeoutException {
+        final long timeout=3000;
+        Runnable fun=() -> Util.sleep(100);
+        runner=createRunner(fun, null)
+          .setJoinTimeout(timeout)
+          .start();
+        Util.waitUntil(2000, 100, () -> runner.state() == running);
+        long start=System.nanoTime();
+        runner.stop(); // will block without https://redhat.atlassian.net/browse/JGRP-3020 for join_timeout ms
+        long time=System.nanoTime() - start;
+        long millis=TimeUnit.NANOSECONDS.toMillis(time);
+        assert millis < 300 // sleep 100ms
+          : String.format("expected to block in stop() less than 300 ms, but blocked for %s", Util.printTime(time));
+        System.out.printf("stop() blocked for %s\n", Util.printTime(time));
+    }
+
     /**
      * Tests the ABA problem (https://issues.redhat.com/browse/JGRP-2919)
      */