[PATCH v8 3/5] selftests/ftrace: Add clear_dynamic_events() to test cases

[PATCH v8 3/5] selftests/ftrace: Add clear_dynamic_events() to test cases

[Steven Rostedt]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

Add a function to remove all dynamic events from the tracing directory. It
requires a loop as some of the dynamic events may depend on others being
removed first. Also add a safety that prevents it from looping infinitely
due to a bug where an event never gets removed.

Link: https://lkml.kernel.org/r/20210819041842.696873153@goodmis.org

Cc: Shuah Khan <shuah@kernel.org>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Cc: linux-kselftest@vger.kernel.org
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 .../testing/selftests/ftrace/test.d/functions | 22 +++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/tools/testing/selftests/ftrace/test.d/functions b/tools/testing/selftests/ftrace/test.d/functions
index a6fac927ee82..f68d336b961b 100644
--- a/tools/testing/selftests/ftrace/test.d/functions
+++ b/tools/testing/selftests/ftrace/test.d/functions
@@ -83,6 +83,27 @@ clear_synthetic_events() { # reset all current synthetic events
     done
 }
 
+clear_dynamic_events() { # reset all current dynamic events
+    again=1
+    stop=1
+    # loop mulitple times as some events require other to be removed first
+    while [ $again -eq 1 ]; do
+	stop=$((stop+1))
+	# Prevent infinite loops
+	if [ $stop -gt 10 ]; then
+	    break;
+	fi
+	again=2
+	grep -v '^#' dynamic_events|
+	while read line; do
+	    del=`echo $line | sed -e 's/^.\([^ ]*\).*/-\1/'`
+	    if ! echo "$del" >> dynamic_events; then
+		again=1
+	    fi
+	done
+    done
+}
+
 initialize_ftrace() { # Reset ftrace to initial-state
 # As the initial state, ftrace will be set to nop tracer,
 # no events, no triggers, no filters, no function filters,
@@ -93,6 +114,7 @@ initialize_ftrace() { # Reset ftrace to initial-state
     reset_events_filter
     reset_ftrace_filter
     disable_events
+    clear_dynamic_events
     [ -f set_event_pid ] && echo > set_event_pid
     [ -f set_ftrace_pid ] && echo > set_ftrace_pid
     [ -f set_ftrace_notrace ] && echo > set_ftrace_notrace
-- 
2.30.2

Re: [PATCH v8 3/5] selftests/ftrace: Add clear_dynamic_events() to test cases

[Masami Hiramatsu]

On Thu, 19 Aug 2021 11:26:07 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:

> From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
> 
> Add a function to remove all dynamic events from the tracing directory. It
> requires a loop as some of the dynamic events may depend on others being
> removed first. Also add a safety that prevents it from looping infinitely
> due to a bug where an event never gets removed.
> 
> Link: https://lkml.kernel.org/r/20210819041842.696873153@goodmis.org
> 

Thank you for adding this useful function!

Acked-by: Masami Hiramatsu <mhiramat@kernel.org>


> Cc: Shuah Khan <shuah@kernel.org>
> Cc: Shuah Khan <skhan@linuxfoundation.org>
> Cc: linux-kselftest@vger.kernel.org
> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> ---
>  .../testing/selftests/ftrace/test.d/functions | 22 +++++++++++++++++++
>  1 file changed, 22 insertions(+)
> 
> diff --git a/tools/testing/selftests/ftrace/test.d/functions b/tools/testing/selftests/ftrace/test.d/functions
> index a6fac927ee82..f68d336b961b 100644
> --- a/tools/testing/selftests/ftrace/test.d/functions
> +++ b/tools/testing/selftests/ftrace/test.d/functions
> @@ -83,6 +83,27 @@ clear_synthetic_events() { # reset all current synthetic events
>      done
>  }
>  
> +clear_dynamic_events() { # reset all current dynamic events
> +    again=1
> +    stop=1
> +    # loop mulitple times as some events require other to be removed first
> +    while [ $again -eq 1 ]; do
> +	stop=$((stop+1))
> +	# Prevent infinite loops
> +	if [ $stop -gt 10 ]; then
> +	    break;
> +	fi
> +	again=2
> +	grep -v '^#' dynamic_events|
> +	while read line; do
> +	    del=`echo $line | sed -e 's/^.\([^ ]*\).*/-\1/'`
> +	    if ! echo "$del" >> dynamic_events; then
> +		again=1
> +	    fi
> +	done
> +    done
> +}
> +
>  initialize_ftrace() { # Reset ftrace to initial-state
>  # As the initial state, ftrace will be set to nop tracer,
>  # no events, no triggers, no filters, no function filters,
> @@ -93,6 +114,7 @@ initialize_ftrace() { # Reset ftrace to initial-state
>      reset_events_filter
>      reset_ftrace_filter
>      disable_events
> +    clear_dynamic_events
>      [ -f set_event_pid ] && echo > set_event_pid
>      [ -f set_ftrace_pid ] && echo > set_ftrace_pid
>      [ -f set_ftrace_notrace ] && echo > set_ftrace_notrace
> -- 
> 2.30.2


-- 
Masami Hiramatsu <mhiramat@kernel.org>

[PATCH v8 4/5] selftests/ftrace: Add selftest for testing eprobe events

[Steven Rostedt]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

Add a test to test event probes, by creating a synthetic event across
sys_enter_openat and sys_exit_openat that passes the filename pointer from
the enter of the system call to the exit, and then add an event probe to
the synthetic event to make sure that the file name is seen.

Link: https://lkml.kernel.org/r/20210819041842.884828019@goodmis.org

Cc: Shuah Khan <shuah@kernel.org>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Cc: linux-kselftest@vger.kernel.org
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 .../test.d/dynevent/add_remove_eprobe.tc      | 53 +++++++++++++++++++
 1 file changed, 53 insertions(+)
 create mode 100644 tools/testing/selftests/ftrace/test.d/dynevent/add_remove_eprobe.tc

diff --git a/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_eprobe.tc b/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_eprobe.tc
new file mode 100644
index 000000000000..7b242f29b916
--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_eprobe.tc
@@ -0,0 +1,53 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: Generic dynamic event - add/remove eprobe events
+# requires: dynamic_events "e[:[<group>/]<event>] <attached-group>.<attached-event> [<args>]":README
+
+echo 0 > events/enable
+
+clear_dynamic_events
+
+SYSTEM="syscalls"
+START="sys_enter_openat"
+END="sys_exit_openat"
+FIELD="filename"
+SYNTH="synth_open"
+EPROBE="eprobe_open"
+
+echo "$SYNTH u64 filename; s64 ret;" > synthetic_events
+echo "hist:keys=common_pid:__arg__1=$FIELD" > events/$SYSTEM/$START/trigger
+echo "hist:keys=common_pid:filename=\$__arg__1,ret=ret:onmatch($SYSTEM.$START).trace($SYNTH,\$filename,\$ret)" > events/$SYSTEM/$END/trigger
+
+echo "e:$EPROBE synthetic/$SYNTH file=+0(\$filename):ustring ret=\$ret:s64" >> dynamic_events
+
+grep -q "$SYNTH" dynamic_events
+grep -q "$EPROBE" dynamic_events
+test -d events/synthetic/$SYNTH
+test -d events/eprobes/$EPROBE
+
+echo 1 > events/eprobes/$EPROBE/enable
+ls
+echo 0 > events/eprobes/$EPROBE/enable
+
+content=`grep '^ *ls-' trace | grep 'file='`
+nocontent=`grep '^ *ls-' trace | grep 'file=' | grep -v -e '"/' -e '"."'` || true
+
+if [ -z "$content" ]; then
+	exit_fail
+fi
+
+if [ ! -z "$nocontent" ]; then
+	exit_fail
+fi
+
+echo "-:$EPROBE" >> dynamic_events
+echo '!'"hist:keys=common_pid:filename=\$__arg__1,ret=ret:onmatch($SYSTEM.$START).trace($SYNTH,\$filename,\$ret)" > events/$SYSTEM/$END/trigger
+echo '!'"hist:keys=common_pid:__arg__1=$FIELD" > events/$SYSTEM/$START/trigger
+echo '!'"$SYNTH u64 filename; s64 ret;" >> synthetic_events
+
+! grep -q "$SYNTH" dynamic_events
+! grep -q "$EPROBE" dynamic_events
+! test -d events/synthetic/$SYNTH
+! test -d events/eprobes/$EPROBE
+
+clear_trace
-- 
2.30.2

Re: [PATCH v8 4/5] selftests/ftrace: Add selftest for testing eprobe events

[Masami Hiramatsu]

On Thu, 19 Aug 2021 11:26:08 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:

> From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
> 
> Add a test to test event probes, by creating a synthetic event across
> sys_enter_openat and sys_exit_openat that passes the filename pointer from
> the enter of the system call to the exit, and then add an event probe to
> the synthetic event to make sure that the file name is seen.
> 
> Link: https://lkml.kernel.org/r/20210819041842.884828019@goodmis.org
> 
> Cc: Shuah Khan <shuah@kernel.org>
> Cc: Shuah Khan <skhan@linuxfoundation.org>
> Cc: linux-kselftest@vger.kernel.org
> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> ---
>  .../test.d/dynevent/add_remove_eprobe.tc      | 53 +++++++++++++++++++
>  1 file changed, 53 insertions(+)
>  create mode 100644 tools/testing/selftests/ftrace/test.d/dynevent/add_remove_eprobe.tc
> 
> diff --git a/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_eprobe.tc b/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_eprobe.tc
> new file mode 100644
> index 000000000000..7b242f29b916
> --- /dev/null
> +++ b/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_eprobe.tc
> @@ -0,0 +1,53 @@
> +#!/bin/sh
> +# SPDX-License-Identifier: GPL-2.0
> +# description: Generic dynamic event - add/remove eprobe events
> +# requires: dynamic_events "e[:[<group>/]<event>] <attached-group>.<attached-event> [<args>]":README
> +
> +echo 0 > events/enable
> +
> +clear_dynamic_events
> +
> +SYSTEM="syscalls"
> +START="sys_enter_openat"
> +END="sys_exit_openat"
> +FIELD="filename"
> +SYNTH="synth_open"
> +EPROBE="eprobe_open"
> +
> +echo "$SYNTH u64 filename; s64 ret;" > synthetic_events
> +echo "hist:keys=common_pid:__arg__1=$FIELD" > events/$SYSTEM/$START/trigger
> +echo "hist:keys=common_pid:filename=\$__arg__1,ret=ret:onmatch($SYSTEM.$START).trace($SYNTH,\$filename,\$ret)" > events/$SYSTEM/$END/trigger

Hmm, can you make this more simple one without synthetic events?
Since synthetic event depends on CONFIG_SYNTH_EVENTS, you need to add
"synth_events" to 'requires' tag.
However, this means that this testcase doesn't run when CONFIG_SYNTH_EVENTS=n
but CONFIG_*PROBE_EVENTS=y.

Thank you,

> +
> +echo "e:$EPROBE synthetic/$SYNTH file=+0(\$filename):ustring ret=\$ret:s64" >> dynamic_events
> +
> +grep -q "$SYNTH" dynamic_events
> +grep -q "$EPROBE" dynamic_events
> +test -d events/synthetic/$SYNTH
> +test -d events/eprobes/$EPROBE
> +
> +echo 1 > events/eprobes/$EPROBE/enable
> +ls
> +echo 0 > events/eprobes/$EPROBE/enable
> +
> +content=`grep '^ *ls-' trace | grep 'file='`
> +nocontent=`grep '^ *ls-' trace | grep 'file=' | grep -v -e '"/' -e '"."'` || true
> +
> +if [ -z "$content" ]; then
> +	exit_fail
> +fi
> +
> +if [ ! -z "$nocontent" ]; then
> +	exit_fail
> +fi
> +
> +echo "-:$EPROBE" >> dynamic_events
> +echo '!'"hist:keys=common_pid:filename=\$__arg__1,ret=ret:onmatch($SYSTEM.$START).trace($SYNTH,\$filename,\$ret)" > events/$SYSTEM/$END/trigger
> +echo '!'"hist:keys=common_pid:__arg__1=$FIELD" > events/$SYSTEM/$START/trigger
> +echo '!'"$SYNTH u64 filename; s64 ret;" >> synthetic_events
> +
> +! grep -q "$SYNTH" dynamic_events
> +! grep -q "$EPROBE" dynamic_events
> +! test -d events/synthetic/$SYNTH
> +! test -d events/eprobes/$EPROBE
> +
> +clear_trace
> -- 
> 2.30.2


-- 
Masami Hiramatsu <mhiramat@kernel.org>

Re: [PATCH v8 4/5] selftests/ftrace: Add selftest for testing eprobe events

[Steven Rostedt]

On Fri, 20 Aug 2021 09:46:39 +0900
Masami Hiramatsu <mhiramat@kernel.org> wrote:

> > +
> > +echo "$SYNTH u64 filename; s64 ret;" > synthetic_events
> > +echo "hist:keys=common_pid:__arg__1=$FIELD" > events/$SYSTEM/$START/trigger
> > +echo "hist:keys=common_pid:filename=\$__arg__1,ret=ret:onmatch($SYSTEM.$START).trace($SYNTH,\$filename,\$ret)" > events/$SYSTEM/$END/trigger  
> 
> Hmm, can you make this more simple one without synthetic events?
> Since synthetic event depends on CONFIG_SYNTH_EVENTS, you need to add
> "synth_events" to 'requires' tag.
> However, this means that this testcase doesn't run when CONFIG_SYNTH_EVENTS=n
> but CONFIG_*PROBE_EVENTS=y.

Sure. I just used this because it was one of the main purposes I was
using it for. I may keep this as a test, but will rename it as
something else, and make a more simple one for just testing the event
probe add and removal.

-- Steve

[PATCH v8 5/5] selftests/ftrace: Add selftest for testing duplicate eprobes and kprobes

[Steven Rostedt]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

Add a selftest that makes sure that eprobes and kprobes can not be created
with the same group and name as existing events.

Cc: Shuah Khan <shuah@kernel.org>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Cc: linux-kselftest@vger.kernel.org
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 .../ftrace/test.d/dynevent/test_duplicates.tc | 28 +++++++++++++++++++
 1 file changed, 28 insertions(+)
 create mode 100644 tools/testing/selftests/ftrace/test.d/dynevent/test_duplicates.tc

diff --git a/tools/testing/selftests/ftrace/test.d/dynevent/test_duplicates.tc b/tools/testing/selftests/ftrace/test.d/dynevent/test_duplicates.tc
new file mode 100644
index 000000000000..022b569267ed
--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/dynevent/test_duplicates.tc
@@ -0,0 +1,28 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: Generic dynamic event - check if duplicate events are caught
+# requires: dynamic_events "e[:[<group>/]<event>] <attached-group>.<attached-event>o [<args>]":README
+
+echo 0 > events/enable
+
+clear_dynamic_events
+
+# first create dynamic events for eprobes and kprobes.
+
+echo 'e:egroup/eevent syscalls/sys_enter_openat file=+0($filename):ustring' >> dynamic_events
+echo 'p:kgroup/kevent vfs_open file=+0($arg2)' >> dynamic_events
+
+# Test eprobe for same eprobe, existing kprobe and existing event
+! echo 'e:egroup/eevent syscalls/sys_enter_openat file=+0($filename):ustring' >> dynamic_events
+! echo 'e:kgroup/kevent syscalls/sys_enter_openat file=+0($filename):ustring' >> dynamic_events
+! echo 'e:syscalls/sys_enter_open syscalls/sys_enter_openat file=+0($filename):ustring' >> dynamic_events
+
+# Test kprobe for same kprobe, existing eprobe and existing event
+! echo 'p:kgroup/kevent vfs_open file=+0($arg2)' >> dynamic_events
+! echo 'p:egroup/eevent vfs_open file=+0($arg2)' >> dynamic_events
+! echo 'p:syscalls/sys_enter_open vfs_open file=+0($arg2)' >> dynamic_events
+
+echo '-:egroup/eevent' >> dynamic_events
+echo '-:kgroup/kevent' >> dynamic_events
+
+clear_trace
-- 
2.30.2

Re: [PATCH v8 5/5] selftests/ftrace: Add selftest for testing duplicate eprobes and kprobes

[Masami Hiramatsu]

On Thu, 19 Aug 2021 11:26:09 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:

> From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
> 
> Add a selftest that makes sure that eprobes and kprobes can not be created
> with the same group and name as existing events.

Hmm, can you also remove kprobe event dependency from this test case?
The event probe depends on CONFIG_PROBE_EVENTS meta config, but that
is enabled both of CONFIG_KPROBE_EVENTS and CONFIG_UPROBE_EVENTS.
This means if the kernel configs CONFIG_KPROBE_EVENTS=n and
CONFIG_UPROBE_EVENTS=y, this will be executed but should fail.

Thank you,

> 
> Cc: Shuah Khan <shuah@kernel.org>
> Cc: Shuah Khan <skhan@linuxfoundation.org>
> Cc: linux-kselftest@vger.kernel.org
> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> ---
>  .../ftrace/test.d/dynevent/test_duplicates.tc | 28 +++++++++++++++++++
>  1 file changed, 28 insertions(+)
>  create mode 100644 tools/testing/selftests/ftrace/test.d/dynevent/test_duplicates.tc
> 
> diff --git a/tools/testing/selftests/ftrace/test.d/dynevent/test_duplicates.tc b/tools/testing/selftests/ftrace/test.d/dynevent/test_duplicates.tc
> new file mode 100644
> index 000000000000..022b569267ed
> --- /dev/null
> +++ b/tools/testing/selftests/ftrace/test.d/dynevent/test_duplicates.tc
> @@ -0,0 +1,28 @@
> +#!/bin/sh
> +# SPDX-License-Identifier: GPL-2.0
> +# description: Generic dynamic event - check if duplicate events are caught
> +# requires: dynamic_events "e[:[<group>/]<event>] <attached-group>.<attached-event>o [<args>]":README
> +
> +echo 0 > events/enable
> +
> +clear_dynamic_events
> +
> +# first create dynamic events for eprobes and kprobes.
> +
> +echo 'e:egroup/eevent syscalls/sys_enter_openat file=+0($filename):ustring' >> dynamic_events
> +echo 'p:kgroup/kevent vfs_open file=+0($arg2)' >> dynamic_events
> +
> +# Test eprobe for same eprobe, existing kprobe and existing event
> +! echo 'e:egroup/eevent syscalls/sys_enter_openat file=+0($filename):ustring' >> dynamic_events
> +! echo 'e:kgroup/kevent syscalls/sys_enter_openat file=+0($filename):ustring' >> dynamic_events
> +! echo 'e:syscalls/sys_enter_open syscalls/sys_enter_openat file=+0($filename):ustring' >> dynamic_events
> +
> +# Test kprobe for same kprobe, existing eprobe and existing event
> +! echo 'p:kgroup/kevent vfs_open file=+0($arg2)' >> dynamic_events
> +! echo 'p:egroup/eevent vfs_open file=+0($arg2)' >> dynamic_events
> +! echo 'p:syscalls/sys_enter_open vfs_open file=+0($arg2)' >> dynamic_events
> +
> +echo '-:egroup/eevent' >> dynamic_events
> +echo '-:kgroup/kevent' >> dynamic_events
> +
> +clear_trace
> -- 
> 2.30.2


-- 
Masami Hiramatsu <mhiramat@kernel.org>

Re: [PATCH v8 5/5] selftests/ftrace: Add selftest for testing duplicate eprobes and kprobes

[Steven Rostedt]

On Fri, 20 Aug 2021 09:53:59 +0900
Masami Hiramatsu <mhiramat@kernel.org> wrote:

> Hmm, can you also remove kprobe event dependency from this test case?
> The event probe depends on CONFIG_PROBE_EVENTS meta config, but that
> is enabled both of CONFIG_KPROBE_EVENTS and CONFIG_UPROBE_EVENTS.
> This means if the kernel configs CONFIG_KPROBE_EVENTS=n and
> CONFIG_UPROBE_EVENTS=y, this will be executed but should fail.

I'll add a check if kprobes are available before testing the kprobes.

-- Steve