From 2e9fcc17a0480e005c91c2e3a6c9dc2f328b2cc1 Mon Sep 17 00:00:00 2001
From: Michal Grich <michal.grich@gmail.com>
Date: Fri, 21 Jul 2023 22:21:39 +0200
Subject: [PATCH] SystemMonitor: Fix calculation of CPU percentage

This commit addresses an issue when 'Zombie' threads are
included in CPU % calculation. This caused negative
time_scheduled_diff, resulting in a data type overflow.
---
 Userland/Applications/SystemMonitor/ProcessModel.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Userland/Applications/SystemMonitor/ProcessModel.cpp b/Userland/Applications/SystemMonitor/ProcessModel.cpp
index 3498a6be68..8c812100cb 100644
--- a/Userland/Applications/SystemMonitor/ProcessModel.cpp
+++ b/Userland/Applications/SystemMonitor/ProcessModel.cpp
@@ -574,6 +574,9 @@ void ProcessModel::update()
             tids_to_remove.append(it.key);
             continue;
         }
+        if (it.value->current_state.state == "Zombie") {
+            continue;
+        }
         auto& thread = *it.value;
         u64 time_scheduled_diff = (thread.current_state.time_user + thread.current_state.time_kernel)
             - (thread.previous_state.time_user + thread.previous_state.time_kernel);