From: Matthew Wilcox <mawilcox@microsoft.com>
Date: Mon, 30 Jan 2017 21:22:30 +0000 (-0500)
Subject: radix_tree_iter_resume: Fix out of bounds error
X-Git-Tag: v4.11-rc1~44^2~9
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=f7137f79c57f228321dde2ab4586015504feaaac;p=karo-tx-linux.git

radix_tree_iter_resume: Fix out of bounds error

The address sanitizer occasionally finds an out of bounds error while
running the test-suite.  It turned out to be a read of the pointer
immediately next to the tree root, but this out of bounds error could
have occurred elsewhere.  This happens because radix_tree_iter_resume()
dereferences 'slot' before checking whether we've come to the end of
the chunk.  We can just delete this line; the value was never used.

Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
---

diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index dcb9a2329e65..c1c079ffadcd 100644
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -1685,7 +1685,6 @@ void **radix_tree_iter_resume(void **slot, struct radix_tree_iter *iter)
 
 	slot++;
 	iter->index = __radix_tree_iter_add(iter, 1);
-	node = rcu_dereference_raw(*slot);
 	skip_siblings(&node, slot, iter);
 	iter->next_index = iter->index;
 	iter->tags = 0;