CVE-2026-64375 proc: protect ptrace_may_access() with exec_update_lock (FD links)

In the Linux kernel, the following vulnerability has been resolved: proc: protect ptracemayaccess with execupdatelock FD links procpidgetlink and procpidreadlink currently look up the task from the pid once, then do the ptrace access check on that task, then look up the task from the pid a second...