[BUGFIX PATCH] kselftest/ftrace: Fix the testcases for kprobes on do_fork

[Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>]

Fix the testcase for kprobes which fails (false positive)
because do_fork is renamed to _do_fork which is introduced
by commit 3033f14ab78c32687 ("clone: support passing tls
argument via C rather than pt_regs magic")

This looks into /proc/kallsyms and checks whether do_fork
or _do_fork exists.

Without this fix (failure logs are removed):
  ----
  # ./ftracetest
  === Ftrace unit tests ===
  [1] Basic trace file check      [PASS]
  [2] Basic test for tracers      [PASS]
  [3] Basic trace clock test      [PASS]
  [4] Basic event tracing check   [PASS]
  [5] event tracing - enable/disable with event level files       [PASS]
  [6] event tracing - enable/disable with subsystem level files   [PASS]
  [7] event tracing - enable/disable with top level files [PASS]
  [8] ftrace - function graph filters with stack tracer   [PASS]
  [9] ftrace - function graph filters     [PASS]
  [10] ftrace - function profiler with function tracing   [PASS]
  [11] Kprobe dynamic event - adding and removing [FAIL]
  [12] Kprobe dynamic event - busy event check    [FAIL]
  [13] Kprobe dynamic event with arguments        [FAIL]
  [14] Kprobe dynamic event with function tracer  [FAIL]
  [15] Kretprobe dynamic event with arguments     [FAIL]

  # of passed:  10
  # of failed:  5
  # of unresolved:  0
  # of untested:  0
  # of unsupported:  0
  # of xfailed:  0
  # of undefined(test bug):  0
  ----

With this fix:
  ----
  # ftracetest
  === Ftrace unit tests ===
  [1] Basic trace file check      [PASS]
  [2] Basic test for tracers      [PASS]
  kselftest/ftrace: Fix the testcases for kprobes on do_fork
  [3] Basic trace clock test      [PASS]
  [4] Basic event tracing check   [PASS]
  [5] event tracing - enable/disable with event level files       [PASS]
  [6] event tracing - enable/disable with subsystem level files   [PASS]
  [7] event tracing - enable/disable with top level files [PASS]
  [8] ftrace - function graph filters with stack tracer   [PASS]
  [9] ftrace - function graph filters     [PASS]
  [10] ftrace - function profiler with function tracing   [PASS]
  [11] Kprobe dynamic event - adding and removing [PASS]
  [12] Kprobe dynamic event - busy event check    [PASS]
  [13] Kprobe dynamic event with arguments        [PASS]
  [14] Kprobe dynamic event with function tracer  [PASS]
  [15] Kretprobe dynamic event with arguments     [PASS]

  # of passed:  15
  # of failed:  0
  # of unresolved:  0
  # of untested:  0
  # of unsupported:  0
  # of xfailed:  0
  # of undefined(test bug):  0
  ----

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Shuah Khan <shuahkh@osg.samsung.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux-api@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
---
 .../ftrace/test.d/kprobe/add_and_remove.tc         |    3 ++-
 .../selftests/ftrace/test.d/kprobe/busy_check.tc   |    3 ++-
 .../selftests/ftrace/test.d/kprobe/kprobe_args.tc  |    3 ++-
 .../ftrace/test.d/kprobe/kprobe_ftrace.tc          |   15 ++++++++-------
 .../ftrace/test.d/kprobe/kretprobe_args.tc         |    3 ++-
 5 files changed, 16 insertions(+), 11 deletions(-)

diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/add_and_remove.tc b/tools/testing/selftests/ftrace/test.d/kprobe/add_and_remove.tc
index a5a4262..345e2ad 100644
--- a/tools/testing/selftests/ftrace/test.d/kprobe/add_and_remove.tc
+++ b/tools/testing/selftests/ftrace/test.d/kprobe/add_and_remove.tc
@@ -2,10 +2,11 @@
 # description: Kprobe dynamic event - adding and removing
 
 [ -f kprobe_events ] || exit_unsupported # this is configurable
+FORK=`grep do_fork$ /proc/kallsyms | cut -f 3 -d" "`
 
 echo 0 > events/enable
 echo > kprobe_events
-echo p:myevent do_fork > kprobe_events
+echo p:myevent $FORK > kprobe_events
 grep myevent kprobe_events
 test -d events/kprobes/myevent
 echo > kprobe_events
diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/busy_check.tc b/tools/testing/selftests/ftrace/test.d/kprobe/busy_check.tc
index d8c7bb6..fe80134 100644
--- a/tools/testing/selftests/ftrace/test.d/kprobe/busy_check.tc
+++ b/tools/testing/selftests/ftrace/test.d/kprobe/busy_check.tc
@@ -2,10 +2,11 @@
 # description: Kprobe dynamic event - busy event check
 
 [ -f kprobe_events ] || exit_unsupported
+FORK=`grep do_fork$ /proc/kallsyms | cut -f 3 -d" "`
 
 echo 0 > events/enable
 echo > kprobe_events
-echo p:myevent do_fork > kprobe_events
+echo p:myevent $FORK > kprobe_events
 test -d events/kprobes/myevent
 echo 1 > events/kprobes/myevent/enable
 echo > kprobe_events && exit 1 # this must fail
diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args.tc b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args.tc
index c45ee27..938b061 100644
--- a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args.tc
+++ b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args.tc
@@ -2,10 +2,11 @@
 # description: Kprobe dynamic event with arguments
 
 [ -f kprobe_events ] || exit_unsupported # this is configurable
+FORK=`grep do_fork$ /proc/kallsyms | cut -f 3 -d" "`
 
 echo 0 > events/enable
 echo > kprobe_events
-echo 'p:testprobe do_fork $stack $stack0 +0($stack)' > kprobe_events
+echo 'p:testprobe '$FORK' $stack $stack0 +0($stack)' > kprobe_events
 grep testprobe kprobe_events
 test -d events/kprobes/testprobe
 echo 1 > events/kprobes/testprobe/enable
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 ab41d2b..51067c9 100644
--- a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_ftrace.tc
+++ b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_ftrace.tc
@@ -3,34 +3,35 @@
 
 [ -f kprobe_events ] || exit_unsupported # this is configurable
 grep function available_tracers || exit_unsupported # this is configurable
+FORK=`grep do_fork$ /proc/kallsyms | cut -f 3 -d" "`
 
 # prepare
 echo nop > current_tracer
-echo do_fork > set_ftrace_filter
+echo $FORK > set_ftrace_filter
 echo 0 > events/enable
 echo > kprobe_events
-echo 'p:testprobe do_fork' > kprobe_events
+echo 'p:testprobe '"$FORK" > kprobe_events
 
 # kprobe on / ftrace off
 echo 1 > events/kprobes/testprobe/enable
 echo > trace
 ( echo "forked")
 grep testprobe trace
-! grep 'do_fork <-' trace
+! grep "$FORK"' <-' trace
 
 # kprobe on / ftrace on
 echo function > current_tracer
 echo > trace
 ( echo "forked")
 grep testprobe trace
-grep 'do_fork <-' trace
+grep "$FORK"' <-' trace
 
 # kprobe off / ftrace on
 echo 0 > events/kprobes/testprobe/enable
 echo > trace
 ( echo "forked")
 ! grep testprobe trace
-grep 'do_fork <-' trace
+grep "$FORK"' <-' trace
 
 # kprobe on / ftrace on
 echo 1 > events/kprobes/testprobe/enable
@@ -38,14 +39,14 @@ echo function > current_tracer
 echo > trace
 ( echo "forked")
 grep testprobe trace
-grep 'do_fork <-' trace
+grep "$FORK"' <-' trace
 
 # kprobe on / ftrace off
 echo nop > current_tracer
 echo > trace
 ( echo "forked")
 grep testprobe trace
-! grep 'do_fork <-' trace
+! grep "$FORK"' <-' trace
 
 # cleanup
 echo nop > current_tracer
diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/kretprobe_args.tc b/tools/testing/selftests/ftrace/test.d/kprobe/kretprobe_args.tc
index 3171798..683d290 100644
--- a/tools/testing/selftests/ftrace/test.d/kprobe/kretprobe_args.tc
+++ b/tools/testing/selftests/ftrace/test.d/kprobe/kretprobe_args.tc
@@ -2,10 +2,11 @@
 # description: Kretprobe dynamic event with arguments
 
 [ -f kprobe_events ] || exit_unsupported # this is configurable
+FORK=`grep do_fork$ /proc/kallsyms | cut -f 3 -d" "`
 
 echo 0 > events/enable
 echo > kprobe_events
-echo 'r:testprobe2 do_fork $retval' > kprobe_events
+echo 'r:testprobe2 '$FORK' $retval' > kprobe_events
 grep testprobe2 kprobe_events
 test -d events/kprobes/testprobe2
 echo 1 > events/kprobes/testprobe2/enable