kernel/resource.c: handle reinsertion of an already-inserted resource
Huang Shijie [Wed, 27 Oct 2010 22:34:52 +0000 (15:34 -0700)]
If the same resource is inserted to the resource tree (maybe not on
purpose), a dead loop will be created.  In this situation, The kernel does
not report any warning or error :(

  The command below will show a endless print.
  #cat /proc/iomem

[akpm@linux-foundation.org: add WARN_ON()]
Signed-off-by: Huang Shijie <shijie8@gmail.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/resource.c

index 7b36976..9c9841c 100644 (file)
@@ -453,6 +453,8 @@ static struct resource * __insert_resource(struct resource *parent, struct resou
 
                if (first == parent)
                        return first;
+               if (WARN_ON(first == new))      /* duplicated insertion */
+                       return first;
 
                if ((first->start > new->start) || (first->end < new->end))
                        break;