From 2573dfb69212dfc08c23a3bb7da11508faea9d22 Mon Sep 17 00:00:00 2001
From: Baptiste Wicht <baptiste.wicht@gmail.com>
Date: Wed, 21 Mar 2018 13:48:45 +0100
Subject: [PATCH] Fix wait_list::remove()

---
 kernel/include/conc/wait_list.hpp |  4 +++-
 kernel/src/conc/wait_list.cpp     | 14 ++++++++++++--
 2 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/kernel/include/conc/wait_list.hpp b/kernel/include/conc/wait_list.hpp
index 8f87c11f..e97014a4 100644
--- a/kernel/include/conc/wait_list.hpp
+++ b/kernel/include/conc/wait_list.hpp
@@ -38,7 +38,9 @@ struct wait_list {
     bool waiting() const;
 
     /*!
-     * \brief Removes the current process from the list
+     * \brief Removes the current process from the list.
+     *
+     * The process must be in the list!
      */
     void remove();
 
diff --git a/kernel/src/conc/wait_list.cpp b/kernel/src/conc/wait_list.cpp
index 3bfd6d48..a257fd39 100644
--- a/kernel/src/conc/wait_list.cpp
+++ b/kernel/src/conc/wait_list.cpp
@@ -38,8 +38,13 @@ void wait_list::remove(){
     auto pid      = scheduler::get_pid();
     auto& process = scheduler::get_process(pid);
 
-    if(head == &process.wait){
-        head = head->next;
+    if (head == &process.wait) {
+        if(head == tail){
+            tail = head = nullptr;
+        } else {
+            head = head->next;
+        }
+
         return;
     }
 
@@ -47,7 +52,12 @@ void wait_list::remove(){
 
     while(node->next){
         if(node->next == &process.wait){
+            if(tail == node->next){
+                tail = node->next->next;
+            }
+
             node->next = node->next->next;
+
             return;
         }