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| author | Konstantin Khlebnikov <koct9i@gmail.com> | 2016-02-05 15:37:01 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-02-25 11:57:49 -0800 |
| commit | c750edf63ce45ff34155723b73828527c1d96353 (patch) | |
| tree | c94edc8c5dbaf27b8ed14a8dc2238556d348cffb | |
| parent | a202017766a111064dc0a99ee38d85886816b27a (diff) | |
| download | lwn-c750edf63ce45ff34155723b73828527c1d96353.tar.gz lwn-c750edf63ce45ff34155723b73828527c1d96353.zip | |
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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | include/linux/radix-tree.h | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h index 699fe2d933c9..e02e09f85fad 100644 --- a/include/linux/radix-tree.h +++ b/include/linux/radix-tree.h @@ -343,7 +343,7 @@ 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; @@ -377,9 +377,9 @@ 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)) |