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

From: Masami Hiramatsu
Date: Fri Oct 23 2015 - 03:57:45 EST


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@xxxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Shuah Khan <shuahkh@xxxxxxxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Cc: linux-api@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
.../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

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