kernel/resource.c: handle reinsertion of an already-inserted resource

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>

1 files changed, 2 insertions, 0 deletions

diff --git a/kernel/resource.c b/kernel/resource.c
index 7b36976e5dea..9c9841cb6902 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -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;