* Masami Hiramatsu <[email protected]> wrote:
> (2013/11/22 11:35), Masami Hiramatsu wrote:
> > (2013/11/21 16:29), Ingo Molnar wrote:
> >>
> >> * Masami Hiramatsu <[email protected]> wrote:
> >>
> >>> (2013/11/21 2:36), Frank Ch. Eigler wrote:
> >>
> >> [ ... ]
> >>>> one needs to resort to something like:
> >>>>
> >>>> # cat /proc/kallsyms | grep ' [tT] ' | while read addr type symbol; do
> >>>> perf probe $symbol
> >>>> done
> >>>>
> >>>> then wait for a few hours for that to finish. Then, or while the loop
> >>>> is still running, run
> >>>>
> >>>> # perf record -e 'probe:*' -aR sleep 1
> >>>>
> >>>> to take a kernel down.
> >>>
> >>> Um, indeed, current blacklist is not perfect. [...]
> >>
> >> Then it needs to be fixed ASAP!
> >
> > OK, I see. At least the two patches included this series
> > should be fixed. :)
> >
> > And more, I need to test all symbols and drills down.
>
> OK, what I've found was;
> - The functions which can be ftraced look good.
> (see tracing/available_filter_functions)
> - following functions should not be able to be probed.
> - memcpy, memset
> - native_load_sp0 and some other native functions (need to be clear)
> - restore
> - trace_graph_return
> - trace_hardirqs_off_thunk, trace_hardirqs_on_thunk
> - This list still be not perfect. I just enabled/disabled kprobes
> one by one. There might be combined bugs (combination of several
> kprobes).
> - Some of them are hard to specify by NOKPROBE_SYMBOL because they are
> defined in assembly file.
>
> Anyway, to fix all of them, I think we need file-based blacklist
> especially for assembler symbols.
assembler symbols shouldn't be particular hard either, just put them
into the noprobes section.
> For example, we can get all text symbols by below command;
> nm some-file.o | grep -i " t " | cut -f3 -d" "
> so that we can make a blacklisted-symbol list for the file.
> I need to look the Kbuild for how I can do that in Makefile.
I think it's generally better to add explicit annotations to the code.
Thanks,
Ingo
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