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    SubjectRe: [PATCH 4/4] perf-probe: Warn if the target function is GNU Indirect function
    * Masami Hiramatsu <mhiramat@kernel.org> [2020-07-09 17:07:31]:

    > Reported-by: Andi Kleen <andi@firstfloor.org>
    > Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
    > ---
    > tools/perf/util/probe-event.c | 5 +++++
    > 1 file changed, 5 insertions(+)
    >
    > diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
    > index 1e95a336862c..671176d39569 100644
    > --- a/tools/perf/util/probe-event.c
    > +++ b/tools/perf/util/probe-event.c
    > @@ -379,6 +379,11 @@ static int find_alternative_probe_point(struct debuginfo *dinfo,
    > address = sym->start;
    > else
    > address = map->unmap_ip(map, sym->start) - map->reloc;
    > + if (sym->type == STT_GNU_IFUNC) {
    > + pr_warning("Warning: The probe address (0x%lx) is in a GNU indirect function.\n"
    > + "This may not work as you expected unless you intend to probe the indirect function.\n",
    > + (unsigned long)address);
    > + }

    Are these GNU indirect functions possible in kernel? If not we could move
    this warning under if (uprobes)

    Also instead of printing the address, can we print the pp->function?

    > break;
    > }
    > if (!address) {
    >

    --
    Thanks and Regards
    Srikar Dronamraju

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