From b9a388f5df546c63c554491b49550fd9bc5262bc Mon Sep 17 00:00:00 2001
From: stswidwinski <stan.swidwinski@gmail.com>
Date: Fri, 21 Jul 2023 13:55:00 -0400
Subject: [PATCH] Retain task states for post stop tasks at the time of node GC
 (#18005)

* Retain task states for post stop tasks at the time of node GC
---
 .changelog/17971.txt               |  3 +++
 client/allocrunner/alloc_runner.go | 13 +++++++++++++
 2 files changed, 16 insertions(+)
 create mode 100644 .changelog/17971.txt

diff --git a/.changelog/17971.txt b/.changelog/17971.txt
new file mode 100644
index 000000000..26ac94bbe
--- /dev/null
+++ b/.changelog/17971.txt
@@ -0,0 +1,3 @@
+```release-note:bug
+client: Fixed a bug where the state of poststop tasks could be corrupted by client gc
+```
diff --git a/client/allocrunner/alloc_runner.go b/client/allocrunner/alloc_runner.go
index 84c1466dd..19474faae 100644
--- a/client/allocrunner/alloc_runner.go
+++ b/client/allocrunner/alloc_runner.go
@@ -734,6 +734,19 @@ func (ar *allocRunner) killTasks() map[string]*structs.TaskState {
 	}
 	wg.Wait()
 
+	// Perform no action on post stop tasks, but retain their states if they exist. This
+	// commonly happens at the time of alloc GC from the client node.
+	for name, tr := range ar.tasks {
+		if !tr.IsPoststopTask() {
+			continue
+		}
+
+		state := tr.TaskState()
+		if state != nil {
+			states[name] = state
+		}
+	}
+
 	return states
 }