From 33b8d7835fa9480a16f1032a61a851f73be83e11 Mon Sep 17 00:00:00 2001
From: Ben Pfaff <blp@cs.stanford.edu>
Date: Sun, 5 Sep 2004 08:14:23 +0000
Subject: [PATCH] free() on a null pointer is a no-op.

---
 src/threads/malloc.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/threads/malloc.c b/src/threads/malloc.c
index 02eee99..7af1156 100644
--- a/src/threads/malloc.c
+++ b/src/threads/malloc.c
@@ -164,6 +164,9 @@ free (void *p)
   struct arena *a = block_to_arena (b);
   struct desc *d = a->desc;
 
+  if (p == NULL)
+    return;
+
   lock_acquire (&d->lock);
 
   /* Add block to free list. */
-- 
2.30.2