On Fri, 14 Jul 2017 14:27:56 -0400 Steven Rostedt <[email protected]> wrote:
> On Fri, 14 Jul 2017 10:58:33 -0400 > Francis Deslauriers <[email protected]> wrote: > > > > Kretprobe on ftrace_ops_assist_func and another function: > > Those crashes are triggered when hooking a kretprobe on the > > ftrace_ops_assist_func symbol and some other functions to make the this > > first > > function reacheable. From my understanding, ftrace_ops_assist_func is the > > function called directly when the kprobe is hit. Thus it should be marked > > with NOKPROBE_SYMBOL. > > > > Hmm, I'm wondering if I should just make an ftrace section, and black > list the entire thing. Also that section could be used to not allow > ftrace to use it either. I've been wanting to start letting ftrace > trace the tracing code, and perf for that matter. It would be nice to > be able to debug things like that. Tracer usually has 2 parts, one is off-line setting part (kicked by user) and another is core online tracing part (which kicked from anywhere). Former can be traced but latter is not. Yeah, I did same thing when I introduced NOKPROBE_SYMBOL() macro. And I also think that is good for kgdb. > I would like to also make sections that can be enabled or disabled in > groups. To group things like the tracing facility and perf and have > them by default not be traced, but then set a flag that says "sure go > ahead and trace them". This shouldn't be too hard to do. We have to notice that is a trigger which allows to shoot yourself in the foot :) Thanks, > > Hmm, I'll add this as another topic to have for the Linux Plumbers > tracing track, as well as the kernel tracing topic. > > -- Steve -- Masami Hiramatsu <[email protected]>
