* Masami Hiramatsu <mhiramat@xxxxxxxxxx> wrote: > Hi, > > Here are the patches of kprobe-based event tracer for x86, version > 5, which allows you to probe various kernel events through ftrace > interface. > > This version supports only x86(-32/-64) (but porting it on other > arch just needs kprobes/kretprobes and register and stack access > APIs). > > This patchset also includes x86(-64) instruction decoder which > supports non-SSE/FP opcodes and includes x86 opcode map. I think > it will be possible to share this opcode map with KVM's decoder. > > This series can be applied on the latest linux-2.6-tip tree. > > This patchset includes following changes: > - Add x86 instruction decoder [1/7] > - Check insertion point safety in kprobe [2/7] > - Cleanup fix_riprel() with insn decoder [3/7] > - Add kprobe-tracer plugin [4/7] > - Fix kernel_trap_sp() on x86 according to systemtap runtime. [5/7] > - Add arch-dep register and stack fetching functions [6/7] > - Support fetching various status (register/stack/memory/etc.) [7/7] > > Future items: > - .init function tracing support. > - Support primitive types(long, ulong, int, uint, etc) for args. Ok, this looks pretty complete already. Two high-level comments: - There's no self-test - would it be possible to add one? See trace_selftest* in kernel/trace/ - No generic integration. It would be nice if these ops: > E.g. > echo p do_sys_open a0 a1 a2 a3 > /debug/tracing/kprobe_events > > This sets a kprobe on the top of do_sys_open() function with recording > 1st to 4th arguments. > > echo r do_sys_open rv rp >> /debug/tracing/kprobe_events were just generally available in just about any other tracer - a bit like the event tracer. It would also be nice to use the 'function attributes' facilities of the function tracer, combined with a new special syntax of the function-filter regex parser, to enable the recovery of return values (or the call arguments), for selected set of functions. For example, today we can already do things like: echo 'sys_read:traceon:4' > /debug/tracing/set_ftrace_filter for 'trace triggers': the above will trigger tracing to be enabled on the entry of sys_read(), 4 times. Likewise, something like: echo 'sys_read:args' > /debug/tracing/set_ftrace_filter echo 'sys_read:return' > /debug/tracing/set_ftrace_filter Could activate kprobes based argument and return-value tracing. Ingo -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
