In the Linux kernel, the following vulnerability has been resolved: serial: protect uartportdtrrts() in uartshutdown() too Commit af224ca2df29 (serial: core: Prevent unsafe uart port access, part 3) added few uport == NULL checks. It added one to uartshutdown(), so the commit assumes, uport can be NULL in there. But right after that protection, there is an unprotected "uartportdtrrts(uport, false);" call. That is invoked only if HUPCL is set, so I assume that is the reason why we do not see lots of these reports. Or it cannot be NULL at this point at all for some reason :P. Until the above is investigated, stay on the safe side and move this dereference to the if too. I got this inconsistency from Coverity under CID 1585130. Thanks.