diff -pruN a/malloc/arena.c b/malloc/arena.c
--- a/malloc/arena.c	2014-01-07 07:07:47.000000000 +0530
+++ b/malloc/arena.c	2014-01-07 14:11:40.093628218 +0530
@@ -702,7 +702,7 @@ heap_trim (heap_info *heap, size_t pad)
       if (!prev_inuse (p)) /* consolidate backward */
         {
           p = prev_chunk (p);
-          unlink (p, bck, fwd);
+	  unlink (ar_ptr, p, bck, fwd);
         }
       assert (((unsigned long) ((char *) p + new_size) & (pagesz - 1)) == 0);
       assert (((char *) p + new_size) == ((char *) heap + heap->size));
diff -pruN a/malloc/hooks.c b/malloc/hooks.c
--- a/malloc/hooks.c	2014-01-07 07:07:47.000000000 +0530
+++ b/malloc/hooks.c	2014-01-07 14:12:41.804625603 +0530
@@ -237,7 +237,9 @@ top_check (void)
         (char *) t + chunksize (t) == mp_.sbrk_base + main_arena.system_mem)))
     return 0;
 
+  mutex_unlock(&main_arena);
   malloc_printerr (check_action, "malloc: top chunk is corrupt", t);
+  mutex_lock(&main_arena);
 
   /* Try to set up a new top chunk. */
   brk = MORECORE (0);
diff -pruN a/malloc/malloc.c b/malloc/malloc.c
--- a/malloc/malloc.c	2014-01-07 07:07:47.000000000 +0530
+++ b/malloc/malloc.c	2014-01-07 14:29:53.370581893 +0530
@@ -1404,11 +1404,15 @@ typedef struct malloc_chunk *mbinptr;
 #define last(b)      ((b)->bk)
 
 /* Take a chunk off a bin list */
-#define unlink(P, BK, FD) {                                            \
+#define unlink(AV, P, BK, FD) {                                            \
     FD = P->fd;								      \
     BK = P->bk;								      \
     if (__builtin_expect (FD->bk != P || BK->fd != P, 0))		      \
-      malloc_printerr (check_action, "corrupted double-linked list", P);      \
+      {									      \
+	mutex_unlock(&(AV)->mutex);					      \
+	malloc_printerr (check_action, "corrupted double-linked list", P);    \
+	mutex_lock(&(AV)->mutex);					      \
+      }									      \
     else {								      \
         FD->bk = BK;							      \
         BK->fd = FD;							      \
@@ -2524,7 +2528,9 @@ sysmalloc (INTERNAL_SIZE_T nb, mstate av
           else if (contiguous (av) && old_size && brk < old_end)
             {
               /* Oops!  Someone else killed our space..  Can't touch anything.  */
+	      mutex_unlock(&av->mutex);
               malloc_printerr (3, "break adjusted to free malloc space", brk);
+	      mutex_lock(&av->mutex);
             }
 
           /*
@@ -3353,7 +3359,9 @@ _int_malloc (mstate av, size_t bytes)
             {
               errstr = "malloc(): memory corruption (fast)";
             errout:
+	      mutex_unlock(&av->mutex);
               malloc_printerr (check_action, errstr, chunk2mem (victim));
+	      mutex_lock(&av->mutex);
               return NULL;
             }
           check_remalloced_chunk (av, victim, nb);
@@ -3441,8 +3449,12 @@ _int_malloc (mstate av, size_t bytes)
           bck = victim->bk;
           if (__builtin_expect (victim->size <= 2 * SIZE_SZ, 0)
               || __builtin_expect (victim->size > av->system_mem, 0))
-            malloc_printerr (check_action, "malloc(): memory corruption",
-                             chunk2mem (victim));
+	    {
+	      void *p = chunk2mem(victim);
+	      mutex_unlock(&av->mutex);
+	      malloc_printerr (check_action, "malloc(): memory corruption", p);
+	      mutex_lock(&av->mutex);
+	    }
           size = chunksize (victim);
 
           /*
@@ -3589,7 +3601,7 @@ _int_malloc (mstate av, size_t bytes)
                 victim = victim->fd;
 
               remainder_size = size - nb;
-              unlink (victim, bck, fwd);
+              unlink (av, victim, bck, fwd);
 
               /* Exhaust */
               if (remainder_size < MINSIZE)
@@ -3694,7 +3706,7 @@ _int_malloc (mstate av, size_t bytes)
               remainder_size = size - nb;
 
               /* unlink */
-              unlink (victim, bck, fwd);
+              unlink (av, victim, bck, fwd);
 
               /* Exhaust */
               if (remainder_size < MINSIZE)
@@ -3832,9 +3844,11 @@ _int_free (mstate av, mchunkptr p, int h
     {
       errstr = "free(): invalid pointer";
     errout:
-      if (!have_lock && locked)
+      if (have_lock || locked)
         (void) mutex_unlock (&av->mutex);
       malloc_printerr (check_action, errstr, chunk2mem (p));
+      if (have_lock)
+	mutex_lock(&av->mutex);
       return;
     }
   /* We know that each chunk is at least MINSIZE bytes in size or a
@@ -3981,7 +3995,7 @@ _int_free (mstate av, mchunkptr p, int h
       prevsize = p->prev_size;
       size += prevsize;
       p = chunk_at_offset(p, -((long) prevsize));
-      unlink(p, bck, fwd);
+      unlink(av, p, bck, fwd);
     }
 
     if (nextchunk != av->top) {
@@ -3990,7 +4004,7 @@ _int_free (mstate av, mchunkptr p, int h
 
       /* consolidate forward */
       if (!nextinuse) {
-	unlink(nextchunk, bck, fwd);
+	unlink(av, nextchunk, bck, fwd);
 	size += nextsize;
       } else
 	clear_inuse_bit_at_offset(nextchunk, 0);
@@ -4151,7 +4165,7 @@ static void malloc_consolidate(mstate av
 	    prevsize = p->prev_size;
 	    size += prevsize;
 	    p = chunk_at_offset(p, -((long) prevsize));
-	    unlink(p, bck, fwd);
+	    unlink(av, p, bck, fwd);
 	  }
 
 	  if (nextchunk != av->top) {
@@ -4159,7 +4173,7 @@ static void malloc_consolidate(mstate av
 
 	    if (!nextinuse) {
 	      size += nextsize;
-	      unlink(nextchunk, bck, fwd);
+	      unlink(av, nextchunk, bck, fwd);
 	    } else
 	      clear_inuse_bit_at_offset(nextchunk, 0);
 
@@ -4228,7 +4242,9 @@ _int_realloc(mstate av, mchunkptr oldp,
     {
       errstr = "realloc(): invalid old size";
     errout:
+      mutex_unlock(&av->mutex);
       malloc_printerr (check_action, errstr, chunk2mem (oldp));
+      mutex_lock(&av->mutex);
       return NULL;
     }
 
@@ -4274,7 +4290,7 @@ _int_realloc(mstate av, mchunkptr oldp,
                (unsigned long) (nb))
         {
           newp = oldp;
-          unlink (next, bck, fwd);
+          unlink (av, next, bck, fwd);
         }
 
       /* allocate, copy, free */