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  1. Core Server
  2. SERVER-33959

CursorManager attempts to dispose of aggregation cursors while holding partitioned lock, which leads to deadlock

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Details

    • Fully Compatible
    • ALL
    • v3.6
    • Query 2018-05-07, Query 2018-05-21
    • 19

    Description

      Attempting to acquire a LockManager lock while holding a mutex is prone to deadlock. The CursorManager::killCursor() function locks the partition of CursorManager::_cursorMap corresponding to the specified cursor id. While holding the mutex, it calls ClientCursor::dispose(), which for an aggregation cursor attempts to acquire the collection lock in DocumentSourceCursor::cleanupExecutor() as part of DocumentSourceCursor::doDispose(). The "listCollections" and "listIndexes" commands hold the collection lock when attempting to call CursorManager::registerCursor(), forming the other edge of the deadlock cycle.

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          is related to

          Bug - A problem which impairs or prevents the functions of the product. SERVER-22541 Aggregation plan executors should be owned by global cursor manager

          • Major - P3 - Major loss of function.
          • Closed

          Task - A task that needs to be done. SERVER-69143 CursorManager no longer needs to handle ClientCursor::dispose() outside of mutexes

          • Major - P3 - Major loss of function.
          • Open

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              charlie.swanson@mongodb.com Charlie Swanson
              max.hirschhorn@mongodb.com Max Hirschhorn
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