952ab9a596
The signal handler thread can use various different runtime resources when processing a SIGHUP (e.g. master-info information) due to calling into reload_acl_and_cache(). Currently, the shutdown process waits for the termination of the signal thread after performing cleanup. However, this could cause resources actively used by the signal handler to be freed while reload_acl_and_cache() is processing. The specific resource that caused MDEV-30260 is a race condition for the hostname_cache, such that mysqld would delete it in clean_up()::hostname_cache_free(), before the signal handler would use it in reload_acl_and_cache()::hostname_cache_refresh(). Another similar resource is the active_mi/master_info_index. There was a race between its deletion by the main thread in end_slave(), and their usage by the Signal Handler as a part of Master_info_index::flush_all_relay_logs.read(active_mi) in reload_acl_and_cache(). This patch fixes these race conditions by relocating where server shutdown waits for the signal handler to die until after server-level threads have been killed (i.e., as a last step of close_connections()). With respect to the hostname_cache, active_mi and master_info_cache, this ensures that they cannot be destroyed while the signal handler is still active, and potentially using them. Additionally: 1) This requires that Events memory is still in place for SIGHUP handling's mysql_print_status(). So event deinitialization is moved into clean_up(), but the event scheduler still needs to be stopped in close_connections() at the same spot. 2) The function kill_server_thread is no longer used, so it is deleted 3) The timeout to wait for the death of the signal thread was not consistent with the comment. The comment mentioned up to 10 seconds, whereas it was actually 0.01s. The code has been fixed to wait up to 10 seconds. 4) A warning has been added if the signal handler thread fails to exit in time. 5) Added pthread_join() to end of wait_for_signal_thread_to_end() if it hadn't ended in 10s with a warning. Note this also removes the pthread_detached attribute from the signal_thread to allow for the pthread_join(). Reviewed By: =========== Vladislav Vaintroub <wlad@mariadb.com> Andrei Elkin <andrei.elkin@mariadb.com> |
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| client | ||
| cmake | ||
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| Docs | ||
| extra | ||
| include | ||
| libmariadb@1d3fd5818a | ||
| libmysqld | ||
| libservices | ||
| man | ||
| mysql-test | ||
| mysys | ||
| mysys_ssl | ||
| plugin | ||
| randgen/conf | ||
| scripts | ||
| sql | ||
| sql-bench | ||
| sql-common | ||
| storage | ||
| strings | ||
| support-files | ||
| tests | ||
| tpool | ||
| unittest | ||
| vio | ||
| win | ||
| wsrep-lib@dfc4bdb8a5 | ||
| zlib | ||
| .clang-format | ||
| .gitattributes | ||
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| .gitlab-ci.yml | ||
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| appveyor.yml | ||
| BUILD-CMAKE | ||
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| config.h.cmake | ||
| configure.cmake | ||
| CONTRIBUTING.md | ||
| COPYING | ||
| CREDITS | ||
| INSTALL-SOURCE | ||
| INSTALL-WIN-SOURCE | ||
| KNOWN_BUGS.txt | ||
| README.md | ||
| THIRDPARTY | ||
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Code status:
ci.appveyor.com
MariaDB: The open source relational database
MariaDB was designed as a drop-in replacement of MySQL(R) with more features, new storage engines, fewer bugs, and better performance.
MariaDB is brought to you by the MariaDB Foundation and the MariaDB Corporation. Please read the CREDITS file for details about the MariaDB Foundation, and who is developing MariaDB.
MariaDB is developed by many of the original developers of MySQL who now work for the MariaDB Corporation, the MariaDB Foundation and by many people in the community.
MySQL, which is the base of MariaDB, is a product and trademark of Oracle Corporation, Inc. For a list of developers and other contributors, see the Credits appendix. You can also run 'SHOW authors' to get a list of active contributors.
A description of the MariaDB project and a manual can be found at:
https://mariadb.com/kb/en/mariadb-vs-mysql-features/
https://mariadb.com/kb/en/mariadb-versus-mysql-compatibility/
https://mariadb.com/kb/en/new-and-old-releases/
Help
More help is available from the Maria Discuss mailing list https://launchpad.net/~maria-discuss, MariaDB's Zulip instance, https://mariadb.zulipchat.com/
Live QA for beginner contributors
MariaDB has a dedicated time each week when we answer new contributor questions live on Zulip. From 8:00 to 10:00 UTC on Mondays, and 10:00 to 12:00 UTC on Thursdays, anyone can ask any questions they’d like, and a live developer will be available to assist.
New contributors can ask questions any time, but we will provide immediate feedback during that interval.
Licensing
NOTE:
MariaDB is specifically available only under version 2 of the GNU General Public License (GPLv2). (I.e. Without the "any later version" clause.) This is inherited from MySQL. Please see the README file in the MySQL distribution for more information.
License information can be found in the COPYING file. Third party license information can be found in the THIRDPARTY file.
Bug Reports
Bug and/or error reports regarding MariaDB should be submitted at: https://jira.mariadb.org
For reporting security vulnerabilities see: https://mariadb.org/about/security-policy/
The code for MariaDB, including all revision history, can be found at: https://github.com/MariaDB/server