From dab8a19d78103380904a4ce814cb22dc7f39128e Mon Sep 17 00:00:00 2001
From: Vincent Latombe <vincent@latombe.net>
Date: Thu, 28 May 2020 15:02:36 +0200
Subject: [PATCH 1/2] Capture stacktrace from the original thread when
 SlaveComputer#_connect fails

---
 core/src/main/java/hudson/slaves/SlaveComputer.java | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/core/src/main/java/hudson/slaves/SlaveComputer.java b/core/src/main/java/hudson/slaves/SlaveComputer.java
index c6d1c56019..59c72ce47d 100644
--- a/core/src/main/java/hudson/slaves/SlaveComputer.java
+++ b/core/src/main/java/hudson/slaves/SlaveComputer.java
@@ -283,6 +283,7 @@ public class SlaveComputer extends Computer {
             logger.fine("Forcing a reconnect on "+getName());
 
         closeChannel();
+        Exception threadInfo = new Exception();
         return lastConnectActivity = Computer.threadPoolForRemoting.submit(() -> {
             // do this on another thread so that the lengthy launch operation
             // (which is typical) won't block UI thread.
@@ -295,16 +296,20 @@ public class SlaveComputer extends Computer {
                     offlineCause = null;
                     launcher.launch(SlaveComputer.this, taskListener);
                 } catch (AbortException e) {
+                    e.addSuppressed(threadInfo);
                     taskListener.error(e.getMessage());
                     throw e;
                 } catch (IOException e) {
+                    e.addSuppressed(threadInfo);
                     Util.displayIOException(e,taskListener);
                     Functions.printStackTrace(e, taskListener.error(Messages.ComputerLauncher_unexpectedError()));
                     throw e;
                 } catch (InterruptedException e) {
+                    e.addSuppressed(threadInfo);
                     Functions.printStackTrace(e, taskListener.error(Messages.ComputerLauncher_abortedLaunch()));
                     throw e;
                 } catch (Exception e) {
+                    e.addSuppressed(threadInfo);
                     Functions.printStackTrace(e, taskListener.error(Messages.ComputerLauncher_unexpectedError()));
                     throw e;
                 }

From 97e8d17ef37976739242d0d590895ba1d95df2cc Mon Sep 17 00:00:00 2001
From: Vincent Latombe <vincent@latombe.net>
Date: Thu, 28 May 2020 15:27:01 +0200
Subject: [PATCH 2/2] Update
 core/src/main/java/hudson/slaves/SlaveComputer.java

Co-authored-by: Jesse Glick <jglick@cloudbees.com>
---
 core/src/main/java/hudson/slaves/SlaveComputer.java | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/core/src/main/java/hudson/slaves/SlaveComputer.java b/core/src/main/java/hudson/slaves/SlaveComputer.java
index 59c72ce47d..7e717744d9 100644
--- a/core/src/main/java/hudson/slaves/SlaveComputer.java
+++ b/core/src/main/java/hudson/slaves/SlaveComputer.java
@@ -283,7 +283,7 @@ public class SlaveComputer extends Computer {
             logger.fine("Forcing a reconnect on "+getName());
 
         closeChannel();
-        Exception threadInfo = new Exception();
+        Throwable threadInfo = new Throwable("launched here");
         return lastConnectActivity = Computer.threadPoolForRemoting.submit(() -> {
             // do this on another thread so that the lengthy launch operation
             // (which is typical) won't block UI thread.