[PATCH 1/3] libtracefs: Fix spelling in test name

[PATCH 1/3] libtracefs: Fix spelling in test name

[Ian Rogers]

Synthetic rather than syntetic.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 utest/tracefs-utest.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/utest/tracefs-utest.c b/utest/tracefs-utest.c
index 0903243..5163004 100644
--- a/utest/tracefs-utest.c
+++ b/utest/tracefs-utest.c
@@ -436,7 +436,7 @@ static void test_synth_compare(struct test_synth *synth, struct tracefs_dynevent
 	CU_TEST(devents[i] == NULL);
 }
 
-static void test_instance_syntetic(struct tracefs_instance *instance)
+static void test_instance_synthetic(struct tracefs_instance *instance)
 {
 	struct test_synth sevents[] = {
 		{"synth_1", "sched", "sched_waking", "sched", "sched_switch", "pid", "next_pid", "pid_match"},
@@ -496,7 +496,7 @@ static void test_instance_syntetic(struct tracefs_instance *instance)
 
 static void test_synthetic(void)
 {
-	test_instance_syntetic(test_instance);
+	test_instance_synthetic(test_instance);
 }
 
 static void test_trace_file(void)
@@ -1706,6 +1706,6 @@ void test_tracefs_lib(void)
 	CU_add_test(suite, "ftrace marker",
 		    test_ftrace_marker);
 	CU_add_test(suite, "kprobes", test_kprobes);
-	CU_add_test(suite, "syntetic events", test_synthetic);
+	CU_add_test(suite, "synthetic events", test_synthetic);
 	CU_add_test(suite, "eprobes", test_eprobes);
 }
-- 
2.35.1.574.g5d30c73bfb-goog

[PATCH 2/3] libtracefs: Avoid null access

[Ian Rogers]

The for loop handles devents == NULL, but the test afterwards needs to
also.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 utest/tracefs-utest.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/utest/tracefs-utest.c b/utest/tracefs-utest.c
index 5163004..7042fa9 100644
--- a/utest/tracefs-utest.c
+++ b/utest/tracefs-utest.c
@@ -433,7 +433,7 @@ static void test_synth_compare(struct test_synth *synth, struct tracefs_dynevent
 		free(event);
 		free(format);
 	}
-	CU_TEST(devents[i] == NULL);
+	CU_TEST(devents == NULL || devents[i] == NULL);
 }
 
 static void test_instance_synthetic(struct tracefs_instance *instance)
-- 
2.35.1.574.g5d30c73bfb-goog

[PATCH 3/3] libtracefs: Move initialization below a null test.

[Ian Rogers]

Computing the address from a NULL pointer results in undefined behavior
which things like undefined behavior sanitizer promote into real
failures.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 src/tracefs-dynevents.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/tracefs-dynevents.c b/src/tracefs-dynevents.c
index 61804b9..8fee474 100644
--- a/src/tracefs-dynevents.c
+++ b/src/tracefs-dynevents.c
@@ -724,13 +724,18 @@ tracefs_dynevent_info(struct tracefs_dynevent *dynevent, char **system,
 		      char **event, char **prefix, char **addr, char **format)
 {
 	char **lv[] = { system, event, prefix, addr, format };
-	char **rv[] = { &dynevent->system, &dynevent->event, &dynevent->prefix,
-			&dynevent->address, &dynevent->format };
+	char **rv[] = { NULL, NULL, NULL, NULL, NULL };
 	int i;
 
 	if (!dynevent)
 		return TRACEFS_DYNEVENT_UNKNOWN;
 
+	rv[0] = &dynevent->system;
+	rv[1] = &dynevent->event;
+	rv[2] = &dynevent->prefix;
+	rv[3] = &dynevent->address;
+	rv[4] = &dynevent->format;
+
 	for (i = 0; i < ARRAY_SIZE(lv); i++) {
 		if (lv[i]) {
 			if (*rv[i]) {
-- 
2.35.1.574.g5d30c73bfb-goog

Re: [PATCH 3/3] libtracefs: Move initialization below a null test.

[Steven Rostedt]

On Thu, 24 Feb 2022 15:48:23 -0800
Ian Rogers <irogers@google.com> wrote:

> Computing the address from a NULL pointer results in undefined behavior
> which things like undefined behavior sanitizer promote into real
> failures.
> 
> Signed-off-by: Ian Rogers <irogers@google.com>
> ---
>  src/tracefs-dynevents.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/src/tracefs-dynevents.c b/src/tracefs-dynevents.c
> index 61804b9..8fee474 100644
> --- a/src/tracefs-dynevents.c
> +++ b/src/tracefs-dynevents.c
> @@ -724,13 +724,18 @@ tracefs_dynevent_info(struct tracefs_dynevent *dynevent, char **system,
>  		      char **event, char **prefix, char **addr, char **format)
>  {
>  	char **lv[] = { system, event, prefix, addr, format };
> -	char **rv[] = { &dynevent->system, &dynevent->event, &dynevent->prefix,
> -			&dynevent->address, &dynevent->format };
> +	char **rv[] = { NULL, NULL, NULL, NULL, NULL };
>  	int i;

I don't really like the NULL initialization done like this.

What about just adding a helper function. That is.

diff --git a/src/tracefs-dynevents.c b/src/tracefs-dynevents.c
index 61804b9d9d5e..48bb26a96c58 100644
--- a/src/tracefs-dynevents.c
+++ b/src/tracefs-dynevents.c
@@ -704,24 +704,9 @@ __hidden int dynevent_get_count(unsigned int types, const char *system)
 	return all;
 }
 
-/**
- * tracefs_dynevent_info - return details of a dynamic event
- * @dynevent: A dynamic event context, describing given dynamic event.
- * @group: return, group in which the dynamic event is configured
- * @event: return, name of the dynamic event
- * @prefix: return, prefix string of the dynamic event
- * @addr: return, the function and offset (or address) of the dynamic event
- * @format: return, the format string of the dynamic event
- *
- * Returns the type of the dynamic event, or TRACEFS_DYNEVENT_UNKNOWN in case of an error.
- * Any of the @group, @event, @prefix, @addr and @format parameters are optional.
- * If a valid pointer is passed, in case of success - a string is allocated and returned.
- * These strings must be freed with free().
- */
-
-enum tracefs_dynevent_type
-tracefs_dynevent_info(struct tracefs_dynevent *dynevent, char **system,
-		      char **event, char **prefix, char **addr, char **format)
+static enum tracefs_dynevent_type
+dynevent_info(struct tracefs_dynevent *dynevent, char **system,
+	      char **event, char **prefix, char **addr, char **format)
 {
 	char **lv[] = { system, event, prefix, addr, format };
 	char **rv[] = { &dynevent->system, &dynevent->event, &dynevent->prefix,
@@ -754,6 +739,30 @@ error:
 	return TRACEFS_DYNEVENT_UNKNOWN;
 }
 
+/**
+ * tracefs_dynevent_info - return details of a dynamic event
+ * @dynevent: A dynamic event context, describing given dynamic event.
+ * @group: return, group in which the dynamic event is configured
+ * @event: return, name of the dynamic event
+ * @prefix: return, prefix string of the dynamic event
+ * @addr: return, the function and offset (or address) of the dynamic event
+ * @format: return, the format string of the dynamic event
+ *
+ * Returns the type of the dynamic event, or TRACEFS_DYNEVENT_UNKNOWN in case of an error.
+ * Any of the @group, @event, @prefix, @addr and @format parameters are optional.
+ * If a valid pointer is passed, in case of success - a string is allocated and returned.
+ * These strings must be freed with free().
+ */
+enum tracefs_dynevent_type
+tracefs_dynevent_info(struct tracefs_dynevent *dynevent, char **system,
+		      char **event, char **prefix, char **addr, char **format)
+{
+	if (!dynevent)
+		return TRACEFS_DYNEVENT_UNKNOWN;
+
+	return dynevent_info(dynevent, system, event, prefix, addr, format);
+}
+
 /**
  * tracefs_dynevent_get_event - return tep event representing the given dynamic event
  * @tep: a handle to the trace event parser context that holds the events


-- Steve

Re: [PATCH 3/3] libtracefs: Move initialization below a null test.

[Ian Rogers]

On Thu, Feb 24, 2022 at 3:56 PM Steven Rostedt <rostedt@goodmis.org> wrote:
>
> On Thu, 24 Feb 2022 15:48:23 -0800
> Ian Rogers <irogers@google.com> wrote:
>
> > Computing the address from a NULL pointer results in undefined behavior
> > which things like undefined behavior sanitizer promote into real
> > failures.
> >
> > Signed-off-by: Ian Rogers <irogers@google.com>
> > ---
> >  src/tracefs-dynevents.c | 9 +++++++--
> >  1 file changed, 7 insertions(+), 2 deletions(-)
> >
> > diff --git a/src/tracefs-dynevents.c b/src/tracefs-dynevents.c
> > index 61804b9..8fee474 100644
> > --- a/src/tracefs-dynevents.c
> > +++ b/src/tracefs-dynevents.c
> > @@ -724,13 +724,18 @@ tracefs_dynevent_info(struct tracefs_dynevent *dynevent, char **system,
> >                     char **event, char **prefix, char **addr, char **format)
> >  {
> >       char **lv[] = { system, event, prefix, addr, format };
> > -     char **rv[] = { &dynevent->system, &dynevent->event, &dynevent->prefix,
> > -                     &dynevent->address, &dynevent->format };
> > +     char **rv[] = { NULL, NULL, NULL, NULL, NULL };
> >       int i;
>
> I don't really like the NULL initialization done like this.
>
> What about just adding a helper function. That is.
>
> diff --git a/src/tracefs-dynevents.c b/src/tracefs-dynevents.c
> index 61804b9d9d5e..48bb26a96c58 100644
> --- a/src/tracefs-dynevents.c
> +++ b/src/tracefs-dynevents.c
> @@ -704,24 +704,9 @@ __hidden int dynevent_get_count(unsigned int types, const char *system)
>         return all;
>  }
>
> -/**
> - * tracefs_dynevent_info - return details of a dynamic event
> - * @dynevent: A dynamic event context, describing given dynamic event.
> - * @group: return, group in which the dynamic event is configured
> - * @event: return, name of the dynamic event
> - * @prefix: return, prefix string of the dynamic event
> - * @addr: return, the function and offset (or address) of the dynamic event
> - * @format: return, the format string of the dynamic event
> - *
> - * Returns the type of the dynamic event, or TRACEFS_DYNEVENT_UNKNOWN in case of an error.
> - * Any of the @group, @event, @prefix, @addr and @format parameters are optional.
> - * If a valid pointer is passed, in case of success - a string is allocated and returned.
> - * These strings must be freed with free().
> - */
> -
> -enum tracefs_dynevent_type
> -tracefs_dynevent_info(struct tracefs_dynevent *dynevent, char **system,
> -                     char **event, char **prefix, char **addr, char **format)
> +static enum tracefs_dynevent_type
> +dynevent_info(struct tracefs_dynevent *dynevent, char **system,
> +             char **event, char **prefix, char **addr, char **format)
>  {
>         char **lv[] = { system, event, prefix, addr, format };
>         char **rv[] = { &dynevent->system, &dynevent->event, &dynevent->prefix,
> @@ -754,6 +739,30 @@ error:
>         return TRACEFS_DYNEVENT_UNKNOWN;
>  }
>
> +/**
> + * tracefs_dynevent_info - return details of a dynamic event
> + * @dynevent: A dynamic event context, describing given dynamic event.
> + * @group: return, group in which the dynamic event is configured
> + * @event: return, name of the dynamic event
> + * @prefix: return, prefix string of the dynamic event
> + * @addr: return, the function and offset (or address) of the dynamic event
> + * @format: return, the format string of the dynamic event
> + *
> + * Returns the type of the dynamic event, or TRACEFS_DYNEVENT_UNKNOWN in case of an error.
> + * Any of the @group, @event, @prefix, @addr and @format parameters are optional.
> + * If a valid pointer is passed, in case of success - a string is allocated and returned.
> + * These strings must be freed with free().
> + */
> +enum tracefs_dynevent_type
> +tracefs_dynevent_info(struct tracefs_dynevent *dynevent, char **system,
> +                     char **event, char **prefix, char **addr, char **format)
> +{
> +       if (!dynevent)
> +               return TRACEFS_DYNEVENT_UNKNOWN;
> +
> +       return dynevent_info(dynevent, system, event, prefix, addr, format);
> +}
> +
>  /**
>   * tracefs_dynevent_get_event - return tep event representing the given dynamic event
>   * @tep: a handle to the trace event parser context that holds the events
>

LGTM. Thanks,

Ian

> -- Steve

Re: [PATCH 3/3] libtracefs: Move initialization below a null test.

[Steven Rostedt]

On Thu, 24 Feb 2022 16:09:29 -0800
Ian Rogers <irogers@google.com> wrote:

> >  /**
> >   * tracefs_dynevent_get_event - return tep event representing the given dynamic event
> >   * @tep: a handle to the trace event parser context that holds the events
> >  
> 
> LGTM. Thanks,

Did you want to resend, or do you want me to just do this myself? I'm good
either way.

-- Steve

Re: [PATCH 3/3] libtracefs: Move initialization below a null test.

[Ian Rogers]

On Thu, Feb 24, 2022 at 4:20 PM Steven Rostedt <rostedt@goodmis.org> wrote:
>
> On Thu, 24 Feb 2022 16:09:29 -0800
> Ian Rogers <irogers@google.com> wrote:
>
> > >  /**
> > >   * tracefs_dynevent_get_event - return tep event representing the given dynamic event
> > >   * @tep: a handle to the trace event parser context that holds the events
> > >
> >
> > LGTM. Thanks,
>
> Did you want to resend, or do you want me to just do this myself? I'm good
> either way.

Happy to let you do it. Thanks,

Ian

> -- Steve