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authorKonstantin Khlebnikov <koct9i@gmail.com>2016-02-05 15:37:01 -0800
committerSasha Levin <sasha.levin@oracle.com>2016-02-15 15:45:37 -0500
commit42362e1f5a73d36fcaf3eb4950dfc17f633ea0d3 (patch)
treec22e9e5f6719d13fa3da4f8ae660b2b62b9e7683
parent4b5eaa857d64ea737c3bed1eb9b3dd201dd2cecf (diff)
downloadlwn-42362e1f5a73d36fcaf3eb4950dfc17f633ea0d3.tar.gz
lwn-42362e1f5a73d36fcaf3eb4950dfc17f633ea0d3.zip
radix-tree: fix oops after radix_tree_iter_retry
[ Upstream commit 732042821cfa106b3c20b9780e4c60fee9d68900 ] Helper radix_tree_iter_retry() resets next_index to the current index. In following radix_tree_next_slot current chunk size becomes zero. This isn't checked and it tries to dereference null pointer in slot. Tagged iterator is fine because retry happens only at slot 0 where tag bitmask in iter->tags is filled with single bit. Fixes: 46437f9a554f ("radix-tree: fix race in gang lookup") Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Matthew Wilcox <willy@linux.intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ohad Ben-Cohen <ohad@wizery.com> Cc: Jeremiah Mahler <jmmahler@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
-rw-r--r--include/linux/radix-tree.h6
1 files changed, 3 insertions, 3 deletions
diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h
index 1a2b2276ffb3..5d5174b59802 100644
--- a/include/linux/radix-tree.h
+++ b/include/linux/radix-tree.h
@@ -391,7 +391,7 @@ void **radix_tree_iter_retry(struct radix_tree_iter *iter)
* @iter: pointer to radix tree iterator
* Returns: current chunk size
*/
-static __always_inline unsigned
+static __always_inline long
radix_tree_chunk_size(struct radix_tree_iter *iter)
{
return iter->next_index - iter->index;
@@ -425,9 +425,9 @@ radix_tree_next_slot(void **slot, struct radix_tree_iter *iter, unsigned flags)
return slot + offset + 1;
}
} else {
- unsigned size = radix_tree_chunk_size(iter) - 1;
+ long size = radix_tree_chunk_size(iter);
- while (size--) {
+ while (--size > 0) {
slot++;
iter->index++;
if (likely(*slot))