| Message ID | 1625864.aO4Q1DYN9d@hactar (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
On Tue, 2016-03-29 at 15:34 -0300, Thiago Jung Bauermann wrote: > Am Dienstag, 29 März 2016, 10:45:57 schrieb Michael Ellerman: > > On Mon, 2016-03-28 at 17:29 -0300, Thiago Jung Bauermann wrote: > > > If I do s/_do_fork/._do_fork/ in kprobe_ftrace.tc then all ftrace kprobe > > > tests pass: > > > > OK. We fixed that in 'perf probe', but not if you're using the sysfs file > > directly. > > > > Do you want to write a patch for ftracetest to try and handle it? I guess > > you'd try "_do_fork" and if that fails then try "._do_fork", and maybe > > only if uname -m says you're running on ppc64? > > I did write a patch yesterday (included below for reference), but then I > noticed that the other ftrace tests use _do_fork and they work fine (I guess > because of the fix you mentioned). I think that ideally the ftrace filter > mechanism should work with dot symbols as well as regular symbols. > > I think this could work by creating a mechanism analogous to the > ARCH_HAS_SYSCALL_MATCH_SYM_NAME one in trace_syscalls.c. Ftrace_match_record > could call it to adjust the symbol name (like kprobe_lookup_name) before > calling ftrace_match. > > But I’m wondering if it’s really worth the effort and maybe patching the > testcase is enough? Also, I don’t know whether my idea would have any > side effects. It'd be nice if it worked properly. Reusing kprobe_lookup_name() looks like it would be the right fix, given this is "kprobe events". cheers
diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_ftrace.tc b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_ftrace.tc index d6f2f49..c3ec5c2 100644 --- a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_ftrace.tc +++ b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_ftrace.tc @@ -4,33 +4,39 @@ [ -f kprobe_events ] || exit_unsupported # this is configurable grep function available_tracers || exit_unsupported # this is configurable +if [ "$(uname -m)" = "ppc64" ]; then + FILTER_FUNCTION="._do_fork" +else + FILTER_FUNCTION="_do_fork" +fi + # prepare echo nop > current_tracer -echo _do_fork > set_ftrace_filter +echo $FILTER_FUNCTION > set_ftrace_filter echo 0 > events/enable echo > kprobe_events -echo 'p:testprobe _do_fork' > kprobe_events +echo "p:testprobe $FILTER_FUNCTION" > kprobe_events # kprobe on / ftrace off echo 1 > events/kprobes/testprobe/enable echo > trace ( echo "forked") grep testprobe trace -! grep '_do_fork <-' trace +! grep "$FILTER_FUNCTION <-" trace # kprobe on / ftrace on echo function > current_tracer echo > trace ( echo "forked") grep testprobe trace -grep '_do_fork <-' trace +grep "$FILTER_FUNCTION <-" trace # kprobe off / ftrace on echo 0 > events/kprobes/testprobe/enable echo > trace ( echo "forked") ! grep testprobe trace -grep '_do_fork <-' trace +grep "$FILTER_FUNCTION <-" trace # kprobe on / ftrace on echo 1 > events/kprobes/testprobe/enable @@ -38,14 +44,14 @@ echo function > current_tracer echo > trace ( echo "forked") grep testprobe trace -grep '_do_fork <-' trace +grep "$FILTER_FUNCTION <-" trace # kprobe on / ftrace off echo nop > current_tracer echo > trace ( echo "forked") grep testprobe trace -! grep '_do_fork <-' trace +! grep "$FILTER_FUNCTION <-" trace # cleanup echo nop > current_tracer