1ab697693f
The `compaction_strategy_state` class holds strategy specific state via
a `std::variant` containing different state types. When a compaction
strategy performs compaction, it retrieves a reference to its state from
the `compaction_strategy_state` object. If the table's compaction
strategy is ALTERed while a compaction is in progress, the
`compaction_strategy_state` object gets replaced, destroying the old
state. This leaves the ongoing compaction holding a dangling reference,
resulting in a use after free.
Fix this by using `seastar::shared_ptr` for the state variant
alternatives(`leveled_compaction_strategy_state_ptr` and
`time_window_compaction_strategy_state_ptr`). The compaction strategies
now hold a copy of the shared_ptr, ensuring the state remains valid for
the duration of the compaction even if the strategy is altered.
The `compaction_strategy_state` itself is still passed by reference and
only the variant alternatives use shared_ptrs. This allows ongoing
compactions to retain ownership of the state independently of the
wrapper's lifetime.
The method `maybe_wait_for_sstable_count_reduction()`, when retrieving
the list of sstables for a possible compaction, holds a reference to the
compaction strategy. If the strategy is updated during execution, it can
cause a use after free issue. To prevent this, hold a copy of the
compaction strategy so it isn’t yanked away during the method’s
execution.
Fixes #25913
Issue probably started after 9d3755f276, so backport to 2025.4
Closes scylladb/scylladb#26593
* github.com:scylladb/scylladb:
compaction: fix use after free when strategy is altered during compaction
compaction/twcs: pass compaction_strategy_state to internal methods
compaction_manager: hold a copy to compaction strategy in maybe_wait_for_sstable_count_reduction
Scylla in-source tests.
For details on how to run the tests, see docs/dev/testing.md
Shared C++ utils, libraries are in lib/, for Python - pylib/
alternator - Python tests which connect to a single server and use the DynamoDB API unit, boost, raft - unit tests in C++ cqlpy - Python tests which connect to a single server and use CQL topology* - tests that set up clusters and add/remove nodes cql - approval tests that use CQL and pre-recorded output rest_api - tests for Scylla REST API Port 9000 scylla-gdb - tests for scylla-gdb.py helper script nodetool - tests for C++ implementation of nodetool
If you can use an existing folder, consider adding your test to it. New folders should be used for new large categories/subsystems, or when the test environment is significantly different from some existing suite, e.g. you plan to start scylladb with different configuration, and you intend to add many tests and would like them to reuse an existing Scylla cluster (clusters can be reused for tests within the same folder).
To add a new folder, create a new directory, and then
copy & edit its suite.ini.