Hi Abhishek, Masami Hiramatsu wrote: >> Hmm, I can not agree, because it is possible to insert a kprobe >> into kprobe's instruction buffer. If it should be a bug, we must >> check it when registering the kprobe. > > I discussed it with other maintainers and knew that current kprobes > does not allow user to insert a kprobe to another kprobe's instruction > buffer, because register_kprobe ensures the insertion address is text. > Now I changed my mind. I think that case (p && kprobe_running() && > kcb->kprobe_status==KPROBE_HIT_SS) is BUG(), even if (*p->ainsn.insn == > BREAKPOINT_INSTRUCTION).
I could understand what the original code did at last. If a kprobe is inserted on a breakpoint which other debugger inserts, it single step inline instead of out-of-line.(this is done in prepare_singlestep) In this case, (p && kprobe_running() && kcb->kprobe_status==KPROBE_HIT_SS) is true and we need pass the control to the debugger. And if (*p->ainsn.insn != BREAKPOINT_INSTRUCTION) (or (p != kprobe_running())) in that case, there may be some bugs. Now I think your original suggestion is correct. Please fix it in another patch. Thank you very much, -- Masami Hiramatsu Software Engineer Hitachi Computer Products (America) Inc. Software Solutions Division e-mail: [EMAIL PROTECTED], [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/
