| From cbf8ae32f66a9ceb8907ad9e16663c2a29e48990 Mon Sep 17 00:00:00 2001 |
| From: Roland Dreier <roland@purestorage.com> |
| Date: Thu, 7 Jun 2012 14:21:13 -0700 |
| Subject: btree: fix tree corruption in btree_get_prev() |
| |
| From: Roland Dreier <roland@purestorage.com> |
| |
| commit cbf8ae32f66a9ceb8907ad9e16663c2a29e48990 upstream. |
| |
| The memory the parameter __key points to is used as an iterator in |
| btree_get_prev(), so if we save off a bkey() pointer in retry_key and |
| then assign that to __key, we'll end up corrupting the btree internals |
| when we do eg |
| |
| longcpy(__key, bkey(geo, node, i), geo->keylen); |
| |
| to return the key value. What we should do instead is use longcpy() to |
| copy the key value that retry_key points to __key. |
| |
| This can cause a btree to get corrupted by seemingly read-only |
| operations such as btree_for_each_safe. |
| |
| [akpm@linux-foundation.org: avoid the double longcpy()] |
| Signed-off-by: Roland Dreier <roland@purestorage.com> |
| Acked-by: Joern Engel <joern@logfs.org> |
| 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> |
| |
| --- |
| lib/btree.c | 4 ++-- |
| 1 file changed, 2 insertions(+), 2 deletions(-) |
| |
| --- a/lib/btree.c |
| +++ b/lib/btree.c |
| @@ -319,8 +319,8 @@ void *btree_get_prev(struct btree_head * |
| |
| if (head->height == 0) |
| return NULL; |
| -retry: |
| longcpy(key, __key, geo->keylen); |
| +retry: |
| dec_key(geo, key); |
| |
| node = head->node; |
| @@ -351,7 +351,7 @@ retry: |
| } |
| miss: |
| if (retry_key) { |
| - __key = retry_key; |
| + longcpy(key, retry_key, geo->keylen); |
| retry_key = NULL; |
| goto retry; |
| } |