radix-tree: fix oops after radix_tree_iter_retry
authorKonstantin Khlebnikov <koct9i@gmail.com>
Fri, 5 Feb 2016 23:37:01 +0000 (15:37 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Sat, 6 Feb 2016 02:10:40 +0000 (18:10 -0800)
commit732042821cfa106b3c20b9780e4c60fee9d68900
tree9e825128f3807b51449536a3301984857db5e412
parentb14fd334ff3dc47b31c3592c166af5ea42b204d3
radix-tree: fix oops after radix_tree_iter_retry

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>
include/linux/radix-tree.h