CVE-2026-74483 binfmt_misc: don't leak the user namespace when the mount fails

In the Linux kernel, the following vulnerability has been resolved: binfmtmisc: don't leak the user namespace when the mount fails bmgettree takes a reference to the user namespace and hands it to gettreekeyed as the sget key. sgetfc moves that reference into sb-sfsinfo and clears fc-sfsinfo, so...