From 1bcff874c52aca3134cee636178ab5d6272fef58 Mon Sep 17 00:00:00 2001
From: Simon Howard
Date: Sun, 26 Apr 2015 18:55:43 -0400
Subject: Don't read currentthinker->next after Z_Free().

Save the next pointer in the P_RunThinkers() loop when iterating through
thinkers, so that if the current thinker is freed we can still advance
to the next thinker without dereferencing freed memory.
---
 src/strife/p_tick.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

(limited to 'src/strife')

diff --git a/src/strife/p_tick.c b/src/strife/p_tick.c
index f4ed2711..c0dd4786 100644
--- a/src/strife/p_tick.c
+++ b/src/strife/p_tick.c
@@ -99,11 +99,13 @@ void P_AllocateThinker (thinker_t*	thinker)
 //
 void P_RunThinkers (void)
 {
-    thinker_t*  currentthinker;
+    thinker_t *currentthinker, *nextthinker;
 
     currentthinker = thinkercap.next;
     while (currentthinker != &thinkercap)
     {
+        nextthinker = currentthinker->next;
+
         if ( currentthinker->function.acv == (actionf_v)(-1) )
         {
             // time to remove it
@@ -116,7 +118,8 @@ void P_RunThinkers (void)
             if (currentthinker->function.acp1)
                 currentthinker->function.acp1 (currentthinker);
         }
-        currentthinker = currentthinker->next;
+
+        currentthinker = nextthinker;
     }
 }
 
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