[PATCH 0/2] selftests: ftrace: Fix multiple-kprobe testcase

[PATCH 0/2] selftests: ftrace: Fix multiple-kprobe testcase

[Masami Hiramatsu]

Hi,

These patches are fixing a bug and improve testcase to
ensure adding 256 kprobe events for test.

The 1st patch is clearly a bug, so it should be fixed
in stable kernel too.

Thank you,

---

Masami Hiramatsu (2):
      [BUGFIX] selftest: ftrace: Fix to pick text symbols for kprobes
      selftest: ftrace: Fix to add 256 kprobe events correctly


 .../ftrace/test.d/kprobe/multiple_kprobes.tc       |   21 +++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

--
Masami Hiramatsu (Linaro) <mhiramat@kernel.org>

[PATCH 1/2] [BUGFIX] selftest: ftrace: Fix to pick text symbols for kprobes

[Masami Hiramatsu]

Fix to pick text symbols for multiple kprobe testcase.
kallsyms shows text symbols with " t " or " T " but
current testcase picks all symbols including "t",
so it picks data symbols if it includes 't' (e.g. "str").

This fixes it to find symbol lines with " t " or " T "
(including spaces).

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Reported-by: Russell King <linux@armlinux.org.uk>
---
 .../ftrace/test.d/kprobe/multiple_kprobes.tc       |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/multiple_kprobes.tc b/tools/testing/selftests/ftrace/test.d/kprobe/multiple_kprobes.tc
index bb16cf91f1b5..e297bd7a2e79 100644
--- a/tools/testing/selftests/ftrace/test.d/kprobe/multiple_kprobes.tc
+++ b/tools/testing/selftests/ftrace/test.d/kprobe/multiple_kprobes.tc
@@ -12,8 +12,8 @@ case `uname -m` in
   *) OFFS=0;;
 esac
 
-echo "Setup up to 256 kprobes"
-grep t /proc/kallsyms | cut -f3 -d" " | grep -v .*\\..* | \
+echo "Setup up kprobes on first 256 text symbols"
+grep -i " t " /proc/kallsyms | cut -f3 -d" " | grep -v .*\\..* | \
 head -n 256 | while read i; do echo p ${i}+${OFFS} ; done > kprobe_events ||:
 
 echo 1 > events/kprobes/enable

[PATCH 2/2] selftest: ftrace: Fix to add 256 kprobe events correctly

[Masami Hiramatsu]

Current multiple-kprobe testcase only tries to add
kprobe events on first 256 text symbols. However
kprobes fails to probe on some text symbols (like
blacklisted symbols). Thus in the worst case,
the test can not add any kprobe events.

To avoid that, continue to try adding kprobe events
until 256 events. Also it confirms the number of
registered kprobe events.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
 .../ftrace/test.d/kprobe/multiple_kprobes.tc       |   19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/multiple_kprobes.tc b/tools/testing/selftests/ftrace/test.d/kprobe/multiple_kprobes.tc
index e297bd7a2e79..ce361b9d62cf 100644
--- a/tools/testing/selftests/ftrace/test.d/kprobe/multiple_kprobes.tc
+++ b/tools/testing/selftests/ftrace/test.d/kprobe/multiple_kprobes.tc
@@ -12,9 +12,24 @@ case `uname -m` in
   *) OFFS=0;;
 esac
 
-echo "Setup up kprobes on first 256 text symbols"
+if [ -d events/kprobes ]; then
+  echo 0 > events/kprobes/enable
+  echo > kprobe_events
+fi
+
+N=0
+echo "Setup up kprobes on first available 256 text symbols"
 grep -i " t " /proc/kallsyms | cut -f3 -d" " | grep -v .*\\..* | \
-head -n 256 | while read i; do echo p ${i}+${OFFS} ; done > kprobe_events ||:
+while read i; do
+  echo p ${i}+${OFFS} >> kprobe_events && N=$((N+1)) ||:
+  test $N -eq 256 && break
+done
+
+L=`wc -l kprobe_events`
+if [ $L -ne $N ]; then
+  echo "The number of kprobes events ($L) is not $N"
+  exit_fail
+fi
 
 echo 1 > events/kprobes/enable
 echo 0 > events/kprobes/enable