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MDEV-17869 AddressSanitizer: use-after-poison in Item_change_list::rollback_item_tree_changes

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it's incorrect to use change_item_tree() to replace arguments
of top-level AND/OR, because they (arguments) are stored in a List,
so a pointer to an argument is in the list_node, and individual
list_node's of top-level AND/OR can be deleted in Item_cond::build_equal_items().
In that case rollback_item_tree_changes() will modify the deleted object.

Luckily, it's not needed to use change_item_tree() for top-level
AND/OR, because the whole top-level item is copied and preserved
in prep_where and prep_on, and restored from there.

So, just don't.

Additionally to the test case in the commit it fixes
* ASAN failure of main.opt_tvc --ps
* ASAN failure of main.having_cond_pushdown --ps
This commit is contained in:
Sergei Golubchik
2022-11-17 19:23:08 +01:00
parent df82d68421
commit 6cb84346e1
8 changed files with 86 additions and 24 deletions
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5
sql/sql_lex.cc
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@ -10042,9 +10042,8 @@ st_select_lex::build_pushable_cond_for_having_pushdown(THD *thd, Item *cond)
*/
if (cond->get_extraction_flag() == FULL_EXTRACTION_FL)
{
Item *result= cond->transform(thd,
&Item::multiple_equality_transformer,
(uchar *)this);
Item *result= cond->top_level_transform(thd,
&Item::multiple_equality_transformer, (uchar *)this);
if (!result)
return true;
if (result->type() == Item::COND_ITEM &&