On Sat, 24 Jun 2017 02:30:21 +0900 Masami Hiramatsu <mhira...@kernel.org> wrote:
> On Thu, 22 Jun 2017 22:33:25 +0530 > "Naveen N. Rao" <naveen.n....@linux.vnet.ibm.com> wrote: > > > On 2017/06/22 06:07PM, Masami Hiramatsu wrote: > > > On Thu, 22 Jun 2017 00:20:28 +0530 > > > "Naveen N. Rao" <naveen.n....@linux.vnet.ibm.com> wrote: > > > > > > > KPROBES_ON_FTRACE is only available on powerpc64le. Update comment to > > > > clarify this. > > > > > > > > Also, we should use an offset of 8 to ensure that the probe does not > > > > fall on ftrace location. The current offset of 4 will fall before the > > > > function local entry point and won't fire, while an offset of 12 or 16 > > > > will fall on ftrace location. Offset 8 is currently guaranteed to not be > > > > the ftrace location. > > > > > > OK, these part seems good to me. > > > > > > > > > > > Finally, do not filter out symbols with a dot. Powerpc Elfv1 uses dot > > > > prefix for all functions and this prevents us from testing some of those > > > > symbols. Furthermore, with the patch to derive event names properly in > > > > the presence of ':' and '.', such names are accepted by kprobe_events > > > > and constitutes a good test for those symbols. > > > > > > Hmm, the reason why I added such filter was to avoid symbols including > > > gcc-generated suffixes like as .constprop or .isra etc. > > > > I see. > > > > I do wonder -- is there a problem if we try probing those symbols? On my > > local x86 vm, I don't see an issue probing it especially with the > > previous patch to enable probing with symbols having a '.' or ':'. > > > > Furthermore, since this is for testing kprobe_events, I feel it is good > > to try probing those symbols too to catch any weird errors we may hit. > > Yes, and that is not what this testcase is aiming to. That testcase should > be a separated one, with correct error handling. Hi Naveen, Here is the testcase which I meant above. This may help if there is any regression related to this specific issue. Thank you, ----- selftests: ftrace: Add a testcase for kprobe event naming From: Masami Hiramatsu <mhira...@kernel.org> Add a testcase for kprobe event naming. This testcase checks whether the kprobe events can automatically ganerate its event name on normal function and dot-suffixed function. Also it checks whether the kprobe events can correctly define new event with given event name and group name. Signed-off-by: Masami Hiramatsu <mhira...@kernel.org> --- .../ftrace/test.d/kprobe/kprobe_eventname.tc | 28 ++++++++++++++++++++ 1 file changed, 28 insertions(+) create mode 100644 tools/testing/selftests/ftrace/test.d/kprobe/kprobe_eventname.tc diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_eventname.tc b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_eventname.tc new file mode 100644 index 0000000..d259031 --- /dev/null +++ b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_eventname.tc @@ -0,0 +1,28 @@ +#!/bin/sh +# description: Kprobe event auto/manual naming + +disable_events +echo > kprobe_events + +:;: "Add an event on function without name" ;: + +FUNC=`grep -m 10 " [tT] [^.]*$" /proc/kallsyms | tail -n 1 | cut -f 3 -d " "` +echo p $FUNC > kprobe_events +test -d events/kprobes/p_${FUNC}_0 || exit_failure + +:;: "Add an event on function with new name" ;: + +echo p:event1 $FUNC > kprobe_events +test -d events/kprobes/event1 || exit_failure + +:;: "Add an event on function with new name and group" ;: + +echo p:kprobes2/event2 $FUNC > kprobe_events +test -d events/kprobes2/event2 || exit_failure + +:;: "Add an event on dot function without name" ;: + +FUNC=`grep -m 10 " [tT] .*\..*$" /proc/kallsyms | tail -n 1 | cut -f 3 -d " "` +echo p $FUNC > kprobe_events +EVENT=`grep $FUNC kprobe_events | cut -f 1 -d " " | cut -f 2 -d:` || exit_failure +test -d events/$EVENT || exit_failure -- Masami Hiramatsu <mhira...@kernel.org>