[MDEV-38463] runtime error: subtraction of unsigned offset … overflowed to … in online ALTER TABLE - Jira

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Details

Type: Bug
Status: Closed (View Workflow)
Priority: Critical
Resolution: Fixed
Affects Version/s: 10.6, 10.11, 11.4, 11.8
Fix Version/s: 10.6.25, 10.11.16, 11.4.10, 11.8.6
Component/s: Storage Engine - InnoDB
Labels:
- overflow
Environment:
Debian GNU/Linux, clang 21.1.8

Bug Category:
Not for Release Notes
Release Note Summary:
This should have no bad effects outside WITH_UBSAN=ON builds.

Description

I noticed this while checking MDEV-37949 test results. The problem turns out to be older. You will need a recent version of clang (I used 21.1.8) and cmake -DWITH_ASAN=ON -DWITH_UBSAN=ON (ASAN could be important for timing; I did not try without it):

mysql-test/mtr --rr innodb.innodb-table-online

rr replay mysql-test/var/log/mysqld.1.rr/latest-trace

10.6 317fb109153b45091003f0b1380b5d68522fce29
innodb.innodb-table-online '8k,clear' w3 [ fail ] Found warnings/errors in server log file!
Test ended at 2026-01-02 09:01:53
line
/mariadb/10.6/storage/innobase/row/row0log.cc:2811:13: runtime error: subtraction of unsigned offset from 0x7b2b56d35000 overflowed to 0x7b2b56da99c9

I started debugging this by setting a breakpoint on __ubsan_handle_pointer_overflow. It is related to an earlier call to row_log_block_allocate().

Attachments

Issue Links

relates to

MDEV-37626 UBSAN: nullptr-with-nonzero-offset/pointer-overflow in row_log_apply_ops

Closed

Activity

People

Assignee:: Thirunarayanan Balathandayuthapani

Reporter:: Marko Mäkelä

Assigned for Implementation:: Marko Mäkelä

Assigned for Review:: Thirunarayanan Balathandayuthapani

Votes:: 0 Vote for this issue

Watchers:: 1 Start watching this issue

Dates

Created:: 13 hours ago

Updated:: 11 hours ago

Resolved:: 11 hours ago

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