BUG/MEDIUM: ebtree: ebmb_insert() must not call cmp_bits on full-length matches

Otherwise we end up comparing the byte past the end, resulting
in duplicate values still being inserted into the tree even if
undesired.

This generally has low impact, though it can sometimes cause one new entry
to be added next to an existing one for stick tables, preventing the results
from being merged.

(cherry picked from commit 12e54ac493a91bb02064568f410592c2700d3933)
This commit is contained in:
Willy Tarreau 2012-06-09 15:43:36 +02:00
parent de5dc0509c
commit a4a1cd1072
2 changed files with 25 additions and 7 deletions

View File

@ -198,7 +198,14 @@ __ebim_insert(struct eb_root *root, struct ebpt_node *new, unsigned int len)
* The last two cases can easily be partially merged.
*/
bit = equal_bits(new->key, old->key, bit, len);
diff = cmp_bits(new->key, old->key, bit);
/* Note: we can compare more bits than the current node's because as
* long as they are identical, we know we descend along the correct
* side. However we don't want to start to compare past the end.
*/
diff = 0;
if (((unsigned)bit >> 3) < len)
diff = cmp_bits(new->key, old->key, bit);
if (diff < 0) {
new->node.leaf_p = new_left;
@ -263,7 +270,14 @@ __ebim_insert(struct eb_root *root, struct ebpt_node *new, unsigned int len)
new->node.node_p = old->node.node_p;
diff = cmp_bits(new->key, old->key, bit);
/* Note: we can compare more bits than the current node's because as
* long as they are identical, we know we descend along the correct
* side. However we don't want to start to compare past the end.
*/
diff = 0;
if (((unsigned)bit >> 3) < len)
diff = cmp_bits(new->key, old->key, bit);
if (diff < 0) {
new->node.leaf_p = new_left;
old->node.node_p = new_rght;

View File

@ -306,12 +306,16 @@ __ebmb_insert(struct eb_root *root, struct ebmb_node *new, unsigned int len)
new_rght = eb_dotag(&new->node.branches, EB_RGHT);
new_leaf = eb_dotag(&new->node.branches, EB_LEAF);
/* Note: we can compare more bits than
* the current node's because as long as they are identical, we
* know we descend along the correct side.
*/
new->node.bit = bit;
diff = cmp_bits(new->key, old->key, bit);
/* Note: we can compare more bits than the current node's because as
* long as they are identical, we know we descend along the correct
* side. However we don't want to start to compare past the end.
*/
diff = 0;
if (((unsigned)bit >> 3) < len)
diff = cmp_bits(new->key, old->key, bit);
if (diff == 0) {
new->node.bit = -1; /* mark as new dup tree, just in case */