[
https://issues.apache.org/jira/browse/IMPALA-8846?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Daniel Becker resolved IMPALA-8846.
-----------------------------------
Resolution: Fixed
> Undefined behaviour in RleEncoder::Put
> --------------------------------------
>
> Key: IMPALA-8846
> URL: https://issues.apache.org/jira/browse/IMPALA-8846
> Project: IMPALA
> Issue Type: Bug
> Reporter: Daniel Becker
> Assignee: Daniel Becker
> Priority: Major
> Attachments: original.txt, with_check.txt
>
>
> On line
> [https://github.com/apache/impala/blob/4000da35be69e469500f5f11e0e5fdec119cf5c7/be/src/util/rle-encoding.h#L346,]
> we test repeat_count_ <= std::numeric_limits<int32_t>::max(), which is
> always true (repeat_count_ is an int), then we increment repeat_count which
> could be std::numeric_limits<int32_t>::max() and overflow, which is undefined
> behaviour for signed integers.
>
> We should either change <= to < or if we think that this never happens,
> remove the misleading check.
> If we correct the check, it may lead to some (probably small) performance
> regression because the compiler could have optimised this out.
--
This message was sent by Atlassian Jira
(v8.3.2#803003)
