On Thu, 29 Mar 2018 14:02:33 -0400 (EDT) Mathieu Desnoyers <mathieu.desnoy...@efficios.com> wrote:
> Currently, anyone using ptrace on a process has pretty much given up all > hopes of performance. Processes will use rseq to gain performance, not the > opposite, so this deterioration will be unwelcome. The ptrace path has nothing to do with ptrace anymore, and probably be hard to notice the performance hit. You simply set a TIF flag, and on exit of the syscall it jumps to a path that checks special cases (tracing system calls being one of them). It's called the ptrace path because ptrace was the first one to use it (I'm guessing, I haven't actually looked at the history). This is used to add any system call checks that are not done during normal operation. And this certainly falls under that category. -- Steve
