From 63926c6e0d8a44c39aab1ced7ca72982083c6493 Mon Sep 17 00:00:00 2001
From: Richard Mortimer <richm@oldelvet.org.uk>
Date: Tue, 18 Mar 2025 10:29:00 +0000
Subject: [PATCH] Process: Clean up process table entry even when `kill(2)`
 fails with `ESRCH` (#10375)

* Icinga daemon leaves zombie processes on very busy system

On a very heavily loaded system the process group kill can
be delayed until after the regular TERM signal has caused
the process to exit. In this situation the waitpid call
is valid and reaps the zombie process that would otherwise
be left behind.

* Update AUTHORS file
---
 AUTHORS              | 1 +
 lib/base/process.cpp | 4 +++-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/AUTHORS b/AUTHORS
index 73ab10637..4207f57f8 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -242,6 +242,7 @@ pv2b <pvz@pvz.pp.se>
 Ralph Breier <ralph.breier@roedl.com>
 Reto Zeder <reto.zeder@arcade.ch>
 Ricardo Bartels <ricardo@bitchbrothers.com>
+Richard Mortimer <richm@oldelvet.org.uk>
 Rinck H. Sonnenberg <r.sonnenberg@netson.nl>
 Robert Lindgren <robert.lindgren@gmail.com>
 Robert Scheck <robert@fedoraproject.org>
diff --git a/lib/base/process.cpp b/lib/base/process.cpp
index a076dcf32..23b735352 100644
--- a/lib/base/process.cpp
+++ b/lib/base/process.cpp
@@ -1087,7 +1087,9 @@ bool Process::DoEvents()
 				Log(LogWarning, "Process")
 					<< "Couldn't kill the process group " << m_PID << " (" << PrettyPrintArguments(m_Arguments)
 					<< "): [errno " << error << "] " << strerror(error);
-				could_not_kill = true;
+				if (error != ESRCH) {
+					could_not_kill = true;
+				}
 			}
 #endif /* _WIN32 */