Re: [BUG] rbtree bug with mmotm 2009-04-14-17-24

[Steve Wise]

Steve Wise wrote:
> Jens Axboe wrote:
>
>  
>
> > > Still crashes with this variant:
> > >     
> >
> > OK, so please try and revert a36e71f996e25d6213f57951f7ae1874086ec57e
> > and see if that works?
> >
> > Or, better yet, please try and revert
> > 55a63998b8967615a15e2211ba0ff3a84a565824 first. If that doesn't work,
> > try the above revert.
> >
> >   
>
> Reverting 55a63998b8967615a15e2211ba0ff3a84a565824 did the trick.
>
>
> Steve.

<snipit from 55a63998b8967615a15e2211ba0ff3a84a565824>

@@ -200,17 +197,14 @@ static void __rb_erase_color(struct rb_node *node, 
struct rb_node *parent,
                       {
                               if (!other->rb_left || 
rb_is_black(other->rb_left))
                               {
-                                       register struct rb_node *o_right;
-                                       if ((o_right = other->rb_right))
-                                               rb_set_black(o_right);
+                                       rb_set_black(other->rb_right);
                                       rb_set_red(other);
                                       __rb_rotate_left(other, root);
                                       other = parent->rb_left;
                               }
                               rb_set_color(other, rb_color(parent));
                               rb_set_black(parent);
-                               if (other->rb_left)
-                                       rb_set_black(other->rb_left);
+                               rb_set_black(other->rb_left);
                               __rb_rotate_right(parent, root);
                               node = root->rb_node;
                               break;


I don't know this code, but isn't the 'if (other->rb_left)' really 
needed?  Or is it always true that if '!other->rb_left' is true entering 
this snipit, then after executing the first 'if' block, then 
'other->rb_left' must be a valid ptr? (how's that for confusing english? :)

Steve


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