kvm tools: fix rbtree-interval search

I've noticed message on kvm exit:

  Warning: serial8250__exit failed.

kvm tool is not able to remove ioport range which was added previously.

The issue is caused by bug in rbtree-interval. Search algorithm in
rb_int_search_single() expects correct value of max_high. But the tree
can contain leaf nodes, which never were updated by propagate_callback().
For this kind of nodes high_max will be 0 and we will not be able to
find and remove them.

Let's initialize max_high on RB_INT_INIT() time.

Fixing this bug makes other bug visible: propagate_callback() can be
called for empty tree: node == NULL. The callback is not ready for empty
tree. Let's fix that as well.

Tested-by: William Dauchy <william@gandi.net>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

diff --git a/tools/kvm/include/kvm/rbtree-interval.h b/tools/kvm/include/kvm/rbtree-interval.h
index e97d05bbc5cac88c8c476b0755d1ec983b1c7f9a..fb2102ab33a61dc3045b2c1a48a7f91c1f8a85ee 100644 (file)
--- a/tools/kvm/include/kvm/rbtree-interval.h
+++ b/tools/kvm/include/kvm/rbtree-interval.h
@@ -4,7 +4,8 @@
 #include <linux/rbtree_augmented.h>
 #include <linux/types.h>
 
-#define RB_INT_INIT(l, h) (struct rb_int_node){.low = l, .high = h}
+#define RB_INT_INIT(l, h) \
+       (struct rb_int_node){.low = l, .high = h, .max_high = h}
 #define rb_int(n) rb_entry(n, struct rb_int_node, node)
 
 struct rb_int_node {

diff --git a/tools/kvm/util/rbtree-interval.c b/tools/kvm/util/rbtree-interval.c
index c82ce985d466cc2651c3e1f63f9b27fc95d5ecfc..d7fa96a06a924a7219455b344996e97caf08fab1 100644 (file)
--- a/tools/kvm/util/rbtree-interval.c
+++ b/tools/kvm/util/rbtree-interval.c
@@ -48,8 +48,12 @@ struct rb_int_node *rb_int_search_range(struct rb_root *root, u64 low, u64 high)
  */
 static void propagate_callback(struct rb_node *node, struct rb_node *stop)
 {
-       struct rb_int_node *i_node = rb_int(node);
+       struct rb_int_node *i_node;
 
+       if (node == stop)
+               return;
+
+       i_node = rb_int(node);
        i_node->max_high = i_node->high;
 
        if (node->rb_left)