[v7,21/36] function_graph: Add selftest for passing local variables
Commit Message
From: Steven Rostedt (VMware) <rostedt@goodmis.org>
Add boot up selftest that passes variables from a function entry to a
function exit, and make sure that they do get passed around.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
Changes in v2:
- Add reserved size test.
- Use pr_*() instead of printk(KERN_*).
---
kernel/trace/trace_selftest.c | 169 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 169 insertions(+)
Comments
On Wed, 7 Feb 2024 00:11:22 +0900
"Masami Hiramatsu (Google)" <mhiramat@kernel.org> wrote:
> From: Steven Rostedt (VMware) <rostedt@goodmis.org>
>
> Add boot up selftest that passes variables from a function entry to a
> function exit, and make sure that they do get passed around.
>
> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> ---
> Changes in v2:
> - Add reserved size test.
> - Use pr_*() instead of printk(KERN_*).
> ---
> kernel/trace/trace_selftest.c | 169 +++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 169 insertions(+)
>
> diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c
> index f0758afa2f7d..4d86cd4c8c8c 100644
> --- a/kernel/trace/trace_selftest.c
> +++ b/kernel/trace/trace_selftest.c
> @@ -756,6 +756,173 @@ trace_selftest_startup_function(struct tracer *trace, struct trace_array *tr)
>
> #ifdef CONFIG_FUNCTION_GRAPH_TRACER
>
> +#ifdef CONFIG_DYNAMIC_FTRACE
> +
> +#define BYTE_NUMBER 123
> +#define SHORT_NUMBER 12345
> +#define WORD_NUMBER 1234567890
> +#define LONG_NUMBER 1234567890123456789LL
> +
> +static int fgraph_store_size __initdata;
> +static const char *fgraph_store_type_name __initdata;
> +static char *fgraph_error_str __initdata;
> +static char fgraph_error_str_buf[128] __initdata;
> +
> +static __init int store_entry(struct ftrace_graph_ent *trace,
> + struct fgraph_ops *gops)
> +{
> + const char *type = fgraph_store_type_name;
> + int size = fgraph_store_size;
> + void *p;
> +
> + p = fgraph_reserve_data(gops->idx, size);
> + if (!p) {
> + snprintf(fgraph_error_str_buf, sizeof(fgraph_error_str_buf),
> + "Failed to reserve %s\n", type);
> + fgraph_error_str = fgraph_error_str_buf;
> + return 0;
> + }
> +
> + switch (fgraph_store_size) {
> + case 1:
> + *(char *)p = BYTE_NUMBER;
> + break;
> + case 2:
> + *(short *)p = SHORT_NUMBER;
> + break;
> + case 4:
> + *(int *)p = WORD_NUMBER;
> + break;
> + case 8:
> + *(long long *)p = LONG_NUMBER;
> + break;
> + }
> +
What would be an interesting test is to run all versions together. That is,
to attach a callback that stores a byte, a callback that stores a short, a
callback that stores a word and a callback that stores a long, and attach
them all to the same function.
I guess we can add that as a separate patch.
-- Steve
> + return 1;
> +}
> +
On Thu, 15 Feb 2024 10:02:54 -0500
Steven Rostedt <rostedt@goodmis.org> wrote:
> On Wed, 7 Feb 2024 00:11:22 +0900
> "Masami Hiramatsu (Google)" <mhiramat@kernel.org> wrote:
>
> > From: Steven Rostedt (VMware) <rostedt@goodmis.org>
> >
> > Add boot up selftest that passes variables from a function entry to a
> > function exit, and make sure that they do get passed around.
> >
> > Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> > Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> > ---
> > Changes in v2:
> > - Add reserved size test.
> > - Use pr_*() instead of printk(KERN_*).
> > ---
> > kernel/trace/trace_selftest.c | 169 +++++++++++++++++++++++++++++++++++++++++
> > 1 file changed, 169 insertions(+)
> >
> > diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c
> > index f0758afa2f7d..4d86cd4c8c8c 100644
> > --- a/kernel/trace/trace_selftest.c
> > +++ b/kernel/trace/trace_selftest.c
> > @@ -756,6 +756,173 @@ trace_selftest_startup_function(struct tracer *trace, struct trace_array *tr)
> >
> > #ifdef CONFIG_FUNCTION_GRAPH_TRACER
> >
> > +#ifdef CONFIG_DYNAMIC_FTRACE
> > +
> > +#define BYTE_NUMBER 123
> > +#define SHORT_NUMBER 12345
> > +#define WORD_NUMBER 1234567890
> > +#define LONG_NUMBER 1234567890123456789LL
> > +
> > +static int fgraph_store_size __initdata;
> > +static const char *fgraph_store_type_name __initdata;
> > +static char *fgraph_error_str __initdata;
> > +static char fgraph_error_str_buf[128] __initdata;
> > +
> > +static __init int store_entry(struct ftrace_graph_ent *trace,
> > + struct fgraph_ops *gops)
> > +{
> > + const char *type = fgraph_store_type_name;
> > + int size = fgraph_store_size;
> > + void *p;
> > +
> > + p = fgraph_reserve_data(gops->idx, size);
> > + if (!p) {
> > + snprintf(fgraph_error_str_buf, sizeof(fgraph_error_str_buf),
> > + "Failed to reserve %s\n", type);
> > + fgraph_error_str = fgraph_error_str_buf;
> > + return 0;
> > + }
> > +
> > + switch (fgraph_store_size) {
> > + case 1:
> > + *(char *)p = BYTE_NUMBER;
> > + break;
> > + case 2:
> > + *(short *)p = SHORT_NUMBER;
> > + break;
> > + case 4:
> > + *(int *)p = WORD_NUMBER;
> > + break;
> > + case 8:
> > + *(long long *)p = LONG_NUMBER;
> > + break;
> > + }
> > +
>
> What would be an interesting test is to run all versions together. That is,
> to attach a callback that stores a byte, a callback that stores a short, a
> callback that stores a word and a callback that stores a long, and attach
> them all to the same function.
>
> I guess we can add that as a separate patch.
Would you mean we should have different callbacks which stores the different
size of data instead of using switch()?
Thank you,
>
> -- Steve
>
>
> > + return 1;
> > +}
> > +
@@ -756,6 +756,173 @@ trace_selftest_startup_function(struct tracer *trace, struct trace_array *tr)
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+#ifdef CONFIG_DYNAMIC_FTRACE
+
+#define BYTE_NUMBER 123
+#define SHORT_NUMBER 12345
+#define WORD_NUMBER 1234567890
+#define LONG_NUMBER 1234567890123456789LL
+
+static int fgraph_store_size __initdata;
+static const char *fgraph_store_type_name __initdata;
+static char *fgraph_error_str __initdata;
+static char fgraph_error_str_buf[128] __initdata;
+
+static __init int store_entry(struct ftrace_graph_ent *trace,
+ struct fgraph_ops *gops)
+{
+ const char *type = fgraph_store_type_name;
+ int size = fgraph_store_size;
+ void *p;
+
+ p = fgraph_reserve_data(gops->idx, size);
+ if (!p) {
+ snprintf(fgraph_error_str_buf, sizeof(fgraph_error_str_buf),
+ "Failed to reserve %s\n", type);
+ fgraph_error_str = fgraph_error_str_buf;
+ return 0;
+ }
+
+ switch (fgraph_store_size) {
+ case 1:
+ *(char *)p = BYTE_NUMBER;
+ break;
+ case 2:
+ *(short *)p = SHORT_NUMBER;
+ break;
+ case 4:
+ *(int *)p = WORD_NUMBER;
+ break;
+ case 8:
+ *(long long *)p = LONG_NUMBER;
+ break;
+ }
+
+ return 1;
+}
+
+static __init void store_return(struct ftrace_graph_ret *trace,
+ struct fgraph_ops *gops)
+{
+ const char *type = fgraph_store_type_name;
+ long long expect = 0;
+ long long found = -1;
+ int size;
+ char *p;
+
+ p = fgraph_retrieve_data(gops->idx, &size);
+ if (!p) {
+ snprintf(fgraph_error_str_buf, sizeof(fgraph_error_str_buf),
+ "Failed to retrieve %s\n", type);
+ fgraph_error_str = fgraph_error_str_buf;
+ return;
+ }
+ if (fgraph_store_size > size) {
+ snprintf(fgraph_error_str_buf, sizeof(fgraph_error_str_buf),
+ "Retrieved size %d is smaller than expected %d\n",
+ size, (int)fgraph_store_size);
+ fgraph_error_str = fgraph_error_str_buf;
+ return;
+ }
+
+ switch (fgraph_store_size) {
+ case 1:
+ expect = BYTE_NUMBER;
+ found = *(char *)p;
+ break;
+ case 2:
+ expect = SHORT_NUMBER;
+ found = *(short *)p;
+ break;
+ case 4:
+ expect = WORD_NUMBER;
+ found = *(int *)p;
+ break;
+ case 8:
+ expect = LONG_NUMBER;
+ found = *(long long *)p;
+ break;
+ }
+
+ if (found != expect) {
+ snprintf(fgraph_error_str_buf, sizeof(fgraph_error_str_buf),
+ "%s returned not %lld but %lld\n", type, expect, found);
+ fgraph_error_str = fgraph_error_str_buf;
+ return;
+ }
+ fgraph_error_str = NULL;
+}
+
+static struct fgraph_ops store_bytes __initdata = {
+ .entryfunc = store_entry,
+ .retfunc = store_return,
+};
+
+static int __init test_graph_storage_type(const char *name, int size)
+{
+ char *func_name;
+ int len;
+ int ret;
+
+ fgraph_store_type_name = name;
+ fgraph_store_size = size;
+
+ snprintf(fgraph_error_str_buf, sizeof(fgraph_error_str_buf),
+ "Failed to execute storage %s\n", name);
+ fgraph_error_str = fgraph_error_str_buf;
+
+ pr_cont("PASSED\n");
+ pr_info("Testing fgraph storage of %d byte%s: ", size, size > 1 ? "s" : "");
+
+ func_name = "*" __stringify(DYN_FTRACE_TEST_NAME);
+ len = strlen(func_name);
+
+ ret = ftrace_set_filter(&store_bytes.ops, func_name, len, 1);
+ if (ret && ret != -ENODEV) {
+ pr_cont("*Could not set filter* ");
+ return -1;
+ }
+
+ ret = register_ftrace_graph(&store_bytes);
+ if (ret) {
+ pr_warn("Failed to init store_bytes fgraph tracing\n");
+ return -1;
+ }
+
+ DYN_FTRACE_TEST_NAME();
+
+ unregister_ftrace_graph(&store_bytes);
+
+ if (fgraph_error_str) {
+ pr_cont("*** %s ***", fgraph_error_str);
+ return -1;
+ }
+
+ return 0;
+}
+/* Test the storage passed across function_graph entry and return */
+static __init int test_graph_storage(void)
+{
+ int ret;
+
+ ret = test_graph_storage_type("byte", 1);
+ if (ret)
+ return ret;
+ ret = test_graph_storage_type("short", 2);
+ if (ret)
+ return ret;
+ ret = test_graph_storage_type("word", 4);
+ if (ret)
+ return ret;
+ ret = test_graph_storage_type("long long", 8);
+ if (ret)
+ return ret;
+ return 0;
+}
+#else
+static inline int test_graph_storage(void) { return 0; }
+#endif /* CONFIG_DYNAMIC_FTRACE */
+
/* Maximum number of functions to trace before diagnosing a hang */
#define GRAPH_MAX_FUNC_TEST 100000000
@@ -913,6 +1080,8 @@ trace_selftest_startup_function_graph(struct tracer *trace,
ftrace_set_global_filter(NULL, 0, 1);
#endif
+ ret = test_graph_storage();
+
/* Don't test dynamic tracing, the function tracer already did */
out:
/* Stop it if we failed */