diff -r 02b341ca3612 tools/libxc/xc_private.c
--- a/tools/libxc/xc_private.c	Wed Aug 18 16:36:25 2010 +0100
+++ b/tools/libxc/xc_private.c	Wed Aug 18 17:22:34 2010 +0100
@@ -49,6 +49,7 @@ xc_interface *xc_interface_open(xentooll
             goto err;
     }
 
+    fprintf(stderr, "%s %p\n", __func__, xch);
     return xch;
 
  err:
@@ -62,6 +63,8 @@ int xc_interface_close(xc_interface *xch
 int xc_interface_close(xc_interface *xch)
 {
     int rc = 0;
+
+    fprintf(stderr, "%s xch:%p\n", __func__, xch);
 
     xtl_logger_destroy(xch->dombuild_logger_tofree);
     xtl_logger_destroy(xch->error_handler_tofree);
@@ -218,14 +221,17 @@ static void _xc_clean_hcall_buf(void *m)
 {
     struct hcall_buf *hcall_buf = m;
 
+    fprintf(stderr, "%s\n", __func__);
     if ( hcall_buf )
     {
         if ( hcall_buf->buf )
         {
+            fprintf(stderr, "%s unlock and free hcall_buf->buf %p\n", __func__, hcall_buf->buf);
             unlock_pages(hcall_buf->buf, PAGE_SIZE);
             free(hcall_buf->buf);
         }
 
+        fprintf(stderr, "%s free hcall_buf %p\n", __func__, hcall_buf);
         free(hcall_buf);
     }
 
@@ -234,11 +240,14 @@ static void _xc_clean_hcall_buf(void *m)
 
 static void _xc_init_hcall_buf(void)
 {
+    fprintf(stderr, "%s\n", __func__);
     pthread_key_create(&hcall_buf_pkey, _xc_clean_hcall_buf);
 }
 
 static void xc_clean_hcall_buf(void)
 {
+    fprintf(stderr, "%s\n", __func__);
+
     pthread_once(&hcall_buf_pkey_once, _xc_init_hcall_buf);
 
     _xc_clean_hcall_buf(pthread_getspecific(hcall_buf_pkey));
@@ -247,6 +256,8 @@ int hcall_buf_prep(void **addr, size_t l
 int hcall_buf_prep(void **addr, size_t len)
 {
     struct hcall_buf *hcall_buf;
+
+    fprintf(stderr, "%s(%p,%zd)\n", __func__, *addr, len);
 
     pthread_once(&hcall_buf_pkey_once, _xc_init_hcall_buf);
 
@@ -257,6 +268,7 @@ int hcall_buf_prep(void **addr, size_t l
         if ( !hcall_buf )
             goto out;
         pthread_setspecific(hcall_buf_pkey, hcall_buf);
+        fprintf(stderr, "%s hcall_buf allocated at %p\n", __func__, hcall_buf);
     }
 
     if ( !hcall_buf->buf )
@@ -268,10 +280,12 @@ int hcall_buf_prep(void **addr, size_t l
             hcall_buf->buf = NULL;
             goto out;
         }
+        fprintf(stderr, "%s hcall_buf->buf allocated at %p\n", __func__, hcall_buf->buf);
     }
 
     if ( (len < PAGE_SIZE) && !hcall_buf->oldbuf )
     {
+        fprintf(stderr, "%s using preallocated buffer at %p for %p\n", __func__, hcall_buf->buf, *addr);
         memcpy(hcall_buf->buf, *addr, len);
         hcall_buf->oldbuf = *addr;
         *addr = hcall_buf->buf;
@@ -279,6 +293,7 @@ int hcall_buf_prep(void **addr, size_t l
     }
 
  out:
+    fprintf(stderr, "%s locking buffer at %p %zd\n", __func__, *addr, len);
     return lock_pages(*addr, len);
 }
 
@@ -286,14 +301,18 @@ void hcall_buf_release(void **addr, size
 {
     struct hcall_buf *hcall_buf = pthread_getspecific(hcall_buf_pkey);
 
+    fprintf(stderr, "%s(%p,%zd)\n", __func__, *addr, len);
+
     if ( hcall_buf && (hcall_buf->buf == *addr) )
     {
+        fprintf(stderr, "%s releasing preallocated buffer at %p for %p\n", __func__, hcall_buf->buf, hcall_buf->oldbuf);
         memcpy(hcall_buf->oldbuf, *addr, len);
         *addr = hcall_buf->oldbuf;
         hcall_buf->oldbuf = NULL;
     }
     else
     {
+        fprintf(stderr, "%s unlocking buffer at %p %zd\n", __func__, *addr, len);
         unlock_pages(*addr, len);
     }
 }