libdb-5.3.21-21.el7

The libdb packages provide the Berkeley Database, an embedded database supporting both traditional and client/server applications.

This update fixes the following bug:

* Previously, the libdb database did not lock its internal buffers in the correct order when it accessed pages located in an off-page duplicate (OPD) tree while processing operations on a cursor. A writer process accessed first the primary tree and then the OPD tree while a reader process did the same in the reverse order. When a writer process accessed a page from the primary tree while a reader process accessed a page from the OPD tree, the processes were unable to access the page from the other tree because the pages were simultaneously locked by the other process. This consequently caused a deadlock in libdb because neither of the processes released their locks. With this update, the btree version of the "cursor->get" method has been modified to lock the tree's pages in the same order as the writing methods, that is, the primary tree first and the OPD tree second. As a result, deadlocks in libdb no longer occur in the described scenario. (BZ#1526929)

Users of libdb are advised to upgrade to these updated packages, which fix this bug.