From: Roland Dreier <[email protected]>
Subject: btree: fix tree corruption in btree_get_prev()
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.
[[email protected]: avoid the double longcpy()]
Signed-off-by: Roland Dreier <[email protected]>
Acked-by: Joern Engel <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
---
lib/btree.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff -puN lib/btree.c~btree-fix-tree-corruption-in-btree_get_prev lib/btree.c
--- a/lib/btree.c~btree-fix-tree-corruption-in-btree_get_prev
+++ a/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;
}
_
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