CVE-2022-48931

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> configfs: fix a race in configfs_{,un}register_subsystem()<br /> <br /> When configfs_register_subsystem() or configfs_unregister_subsystem()<br /> is executing link_group() or unlink_group(),<br /> it is possible that two processes add or delete list concurrently.<br /> Some unfortunate interleavings of them can cause kernel panic.<br /> <br /> One of cases is:<br /> A --&gt; B --&gt; C --&gt; D<br /> A next = next |<br /> | // prev == B<br /> | prev-&gt;next = next<br /> <br /> Fix this by adding mutex when calling link_group() or unlink_group(),<br /> but parent configfs_subsystem is NULL when config_item is root.<br /> So I create a mutex configfs_subsystem_mutex.