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  1. MariaDB MaxScale
  2. MXS-329

The session pointer in a DCB can be null unexpectedly

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Details

    • Bug
    • Status: Closed (View Workflow)
    • Major
    • Resolution: Fixed
    • 1.2.0
    • 1.3.0
    • Core
    • None
    • All

    Description

      In the current develop branch, line 379 of mysql_backend.c is: service_refresh_users(dcb->session->service); this will naturally fail and cause a crash if dcb->session is NULL. It seems that this situation can arise.

      In the case in point, the DCB was in state DCB_STATE_POLLING, which implies that the DCB had not been processed by the zombie mechanism. Nor was there any indication of corruption.

      The big question here is whether there are any rules for when dcb->session may be null. Most of the time it isn't NULL, but obviously sometimes it is. How did it come to be NULL?

      Does code have to assume that dcb->session could become NULL at any time? Or are there known circumstances where it is safe to assume that it will not be NULL?

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          causes

          Bug - A problem which impairs or prevents the functions of the product. MXS-414 Maxscale crashed every day!

          • Blocker - Blocks development and/or testing work, production could not run.
          • Closed
          includes

          New Feature - A new feature of the product, which has yet to be developed. MXS-330 Insufficient error handling in httpd.c

          • Major - Major loss of function.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. MXS-351 Router error handling can cause crash by leaving dangling DCB pointer

          • Blocker - Blocks development and/or testing work, production could not run.
          • Closed
          relates to

          Bug - A problem which impairs or prevents the functions of the product. MXS-207 MaxScale received fatal signal 11 (libreadwritesplit)

          • Blocker - Blocks development and/or testing work, production could not run.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. MXS-415 MaxScale 1.2.1 crashed with Signal 6 and 11

          • Blocker - Blocks development and/or testing work, production could not run.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. MXS-198 MaxScale received fatal signal 11

          • Blocker - Blocks development and/or testing work, production could not run.
          • Closed

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              martin brampton martin brampton (Inactive)
              martin brampton martin brampton (Inactive)
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              Dates

                Created:
                Updated:
                Resolved:

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