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authorKonstantin Khlebnikov <koct9i@gmail.com>2016-02-05 15:37:01 -0800
committerJiri Slaby <jslaby@suse.cz>2016-02-25 10:49:16 +0100
commit135bf262ed99bfbbaaff963b05d4add55ff8c4ab (patch)
tree320beda27a5b0911458a29ae71c8c9671575049f
parent44e026574e970b19ce548b659459ed8286cc5a44 (diff)
radix-tree: fix oops after radix_tree_iter_retry
commit 732042821cfa106b3c20b9780e4c60fee9d68900 upstream. 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> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
-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 3c2ce3cdd16a..16604454e95f 100644
--- a/include/linux/radix-tree.h
+++ b/include/linux/radix-tree.h
@@ -341,7 +341,7 @@ 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;
@@ -375,9 +375,9 @@ 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))