[IMPALA-11416] SlotRef::tuple_is_nullable_ uninitialised for struct children

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: Impala 4.2.0, Impala 4.1.1
• Component/s: Backend
• Epic Color: ghx-label-10

Language

C++

• Assignee: Daniel Becker
• Reporter: Daniel Becker
• Created: 05/Jul/22 11:41
• Updated: 23/Aug/22 05:48
• Resolved: 01/Aug/22 08:44

Description

In SlotRef::Init, tuple_is_nullable_ is only assigned a value if the SlotRef is not within a struct:

if (!slot_desc_->parent()->isTupleOfStructSlot()) {
      tuple_is_nullable_ = row_desc.TupleIsNullable(tuple_idx_);
}

https://github.com/apache/impala/blob/fefb9f24be1f99ac0077a8d6ef00834d8e90ef45/be/src/exprs/slot-ref.cc#L103

Otherwise tuple_is_nullable_ remains uninitialised, leading to undefined behaviour when it is read.