(2013/04/05 11:39), Namhyung Kim wrote: > From: Namhyung Kim <[email protected]> > > Some of kernel functions are not allowed to be used by kprobes for > some reason, so they're marked as __kprobe on the source code and > reside on ".kprobes.text" section. > > However normal users which only see /proc/kallsyms don't know about > them and would get only general error message when tried to add a > probe on such function.
Right, > > $ sudo ./perf probe do_page_fault > Failed to find path of kernel module. > Added new event: > Failed to write event: Invalid argument > Error: Failed to add events. (-1) > > This patch enhance it by checking the special kprobes section address > and if to-be-probed function address is in the section, it would print > like this: > > $ sudo ./perf probe do_page_fault > Failed to find path of kernel module. > Added new event: > Failed to write event: kprobes is not allowed for this function. > Error: Failed to add events. (-1) Yeah, I agree that it is hard to know for perf probe users. However, your implementation strongly depends on the current kernel, I think we'd better export __kprobe_text_* as macros of symbol strings in kprobes.h, and reuse it. Or, export such no-probe symbols via /sys/kernel/debug/kprobes/noprobe_syms Thank you, -- Masami HIRAMATSU IT Management Research Dept. Linux Technology Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: [email protected] -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
