Messages in this thread Patch in this message | | | Subject | [PATCH] radix-tree: fix oops after radix_tree_iter_retry | From | Konstantin Khlebnikov <> | Date | Thu, 04 Feb 2016 11:41:27 +0300 |
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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.
Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Fixes: 46437f9a554f ("radix-tree: fix race in gang lookup") Cc: Matthew Wilcox <willy@linux.intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ohad Ben-Cohen <ohad@wizery.com> Cc: <stable@vger.kernel.org> --- include/linux/radix-tree.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h index 00b17c526c1f..f54be7082207 100644 --- a/include/linux/radix-tree.h +++ b/include/linux/radix-tree.h @@ -400,7 +400,7 @@ 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; @@ -434,9 +434,9 @@ 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))
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