Uploaded image for project: 'MariaDB MaxScale'
  1. MariaDB MaxScale
  2. MXS-329

The session pointer in a DCB can be null unexpectedly

    XMLWordPrintable

    Details

    • Type: Bug
    • Status: Closed (View Workflow)
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: 1.2.0
    • Fix Version/s: 1.3.0
    • Component/s: Core
    • Labels:
      None
    • Environment:
      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?

        Attachments

          Issue Links

            Activity

              People

              Assignee:
              martin brampton martin brampton (Inactive)
              Reporter:
              martin brampton martin brampton (Inactive)
              Votes:
              0 Vote for this issue
              Watchers:
              5 Start watching this issue

                Dates

                Created:
                Updated:
                Resolved:

                  Git Integration

                  Error rendering 'com.xiplink.jira.git.jira_git_plugin:git-issue-webpanel'. Please contact your Jira administrators.