On Thu, 22 Feb 2024 11:18:33 +0100 Jiri Olsa <olsajiri@xxxxxxxxx> wrote: > There's few ongoing kprobe multi features that I'd like to give an update > about and discuss. > > - Support to execute bpf program for both entry and return probes. This > way we don't need to create 2 links when we need to run bpf program on > entry/return probes of the same function, first rfc posted [0]. > > - In addition to above feature introduce shared 'session' data between > entry and exit probe accessible from bpf program, originally discussed > in [1]. > > - Allow to use per program re-entry checks instead of current hard coded > per cpu re-entry check, or just change to per program check directly. > > - There's ongoing development of patchset moving fprobe implementation > from function tracer on top of fgraph tracer by Masami Hiramatsu [2]. > As kprobe multi link is implemented via fprobe I'd like to give an > update what this change means for kprobe multi link. And now I updated the series.[3] This changes the ftrace_regs accessible registers according to the context. In entry probe, no change, but exit probe can only access return value, return address (as instruction pointer) and frame pointer if available. [3] https://lore.kernel.org/all/170887410337.564249.6360118840946697039.stgit@devnote2/ Thanks, > > > [0] https://lore.kernel.org/bpf/20240207153550.856536-1-jolsa@xxxxxxxxxx/ > [1] https://lore.kernel.org/bpf/CAEf4Bzb6sPXAtDVke=CtCXev0mxhfgEG_O-xUA-e9-8NnbBtJQ@xxxxxxxxxxxxxx/ > [2] https://lore.kernel.org/bpf/170723204881.502590.11906735097521170661.stgit@devnote2/ -- Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
