X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=src%2Fthreads%2Fmalloc.c;h=8e6b4591ea87ecae09337ae5d741c89a68bdcb9a;hb=715ca79351a7f4cd3bed471e1cae934f24b5ed09;hp=487e93875ef4124ac314a7355429d4c2a632d1ab;hpb=8382bdd7884a6d38f7529e0517dd9a7083f4ce73;p=pintos-anon

diff --git a/src/threads/malloc.c b/src/threads/malloc.c
index 487e938..8e6b459 100644
--- a/src/threads/malloc.c
+++ b/src/threads/malloc.c
@@ -161,7 +161,7 @@ calloc (size_t a, size_t b)
   void *p;
   size_t size;
 
-  /* Calculate block size. */
+  /* Calculate block size and make sure it fits in size_t. */
   size = a * b;
   if (size < a || size < b)
     return NULL;
@@ -198,7 +198,7 @@ free (void *p)
     }
 
 #ifndef NDEBUG
-  memset (b, 0xcd, d->block_size);
+  memset (b, 0xcc, d->block_size);
 #endif
   
   lock_acquire (&d->lock);
@@ -228,8 +228,16 @@ static struct arena *
 block_to_arena (struct block *b)
 {
   struct arena *a = pg_round_down (b);
+
+  /* Check that the arena is valid. */
   ASSERT (a != NULL);
   ASSERT (a->magic == ARENA_MAGIC);
+
+  /* Check that the block is properly aligned for the arena. */
+  ASSERT (a->desc == NULL
+          || (pg_ofs (b) - sizeof *a) % a->desc->block_size == 0);
+  ASSERT (a->desc != NULL || pg_ofs (b) == sizeof *a);
+
   return a;
 }