diff mbox series

[v2,3/7] tracing/probes: cleanup: Set trace_probe::nr_args at trace_probe_init

Message ID 170891990355.609861.2805086066595778818.stgit@devnote2
State New
Headers
Series tracing/probes: Support function parameter access from return probe |

Commit Message

Masami Hiramatsu (Google) Feb. 26, 2024, 3:58 a.m. UTC 
  From: Masami Hiramatsu (Google) <mhiramat@kernel.org>

Instead of incrementing the trace_probe::nr_args, init it at trace_probe_init().
This is a cleanup, so the behavior is not changed.

Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
 kernel/trace/trace_eprobe.c |    2 +-
 kernel/trace/trace_probe.c  |   10 ++++++----
 kernel/trace/trace_probe.h  |    2 +-
 kernel/trace/trace_uprobe.c |    2 +-
 4 files changed, 9 insertions(+), 7 deletions(-)

Comments

Steven Rostedt March 1, 2024, 3:37 a.m. UTC | #1 
On Mon, 26 Feb 2024 12:58:23 +0900
"Masami Hiramatsu (Google)" <mhiramat@kernel.org> wrote:

> From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> 
> Instead of incrementing the trace_probe::nr_args, init it at trace_probe_init().
> This is a cleanup, so the behavior is not changed.

The change is fine, but the change log does not say why this was done.

Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>

-- Steve


> 
> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> ---
Masami Hiramatsu (Google) March 3, 2024, 3:48 p.m. UTC | #2 
On Thu, 29 Feb 2024 22:37:53 -0500
Steven Rostedt <rostedt@goodmis.org> wrote:

> On Mon, 26 Feb 2024 12:58:23 +0900
> "Masami Hiramatsu (Google)" <mhiramat@kernel.org> wrote:
> 
> > From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> > 
> > Instead of incrementing the trace_probe::nr_args, init it at trace_probe_init().
> > This is a cleanup, so the behavior is not changed.
> 
> The change is fine, but the change log does not say why this was done.

This change is to get the number of trace_probe arguments while parsing
the argument strings.

Thank you,

> 
> Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
> 
> -- Steve
> 
> 
> > 
> > Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> > ---
diff mbox series

Patch

diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c
index 03c851f57969..eb72def7410f 100644
--- a/kernel/trace/trace_eprobe.c
+++ b/kernel/trace/trace_eprobe.c
@@ -220,7 +220,7 @@  static struct trace_eprobe *alloc_event_probe(const char *group,
 	if (!ep->event_system)
 		goto error;
 
-	ret = trace_probe_init(&ep->tp, this_event, group, false);
+	ret = trace_probe_init(&ep->tp, this_event, group, false, nargs);
 	if (ret < 0)
 		goto error;
 
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index 67a0b9cbb648..93f36f8a108e 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -1423,9 +1423,6 @@  int traceprobe_parse_probe_arg(struct trace_probe *tp, int i, const char *arg,
 	struct probe_arg *parg = &tp->args[i];
 	const char *body;
 
-	/* Increment count for freeing args in error case */
-	tp->nr_args++;
-
 	body = strchr(arg, '=');
 	if (body) {
 		if (body - arg > MAX_ARG_NAME_LEN) {
@@ -1810,7 +1807,7 @@  void trace_probe_cleanup(struct trace_probe *tp)
 }
 
 int trace_probe_init(struct trace_probe *tp, const char *event,
-		     const char *group, bool alloc_filter)
+		     const char *group, bool alloc_filter, int nargs)
 {
 	struct trace_event_call *call;
 	size_t size = sizeof(struct trace_probe_event);
@@ -1846,6 +1843,11 @@  int trace_probe_init(struct trace_probe *tp, const char *event,
 		goto error;
 	}
 
+	tp->nr_args = nargs;
+	/* Make sure pointers in args[] are NULL */
+	if (nargs)
+		memset(tp->args, 0, sizeof(tp->args[0]) * nargs);
+
 	return 0;
 
 error:
diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
index c1877d018269..ed8d1052f8a7 100644
--- a/kernel/trace/trace_probe.h
+++ b/kernel/trace/trace_probe.h
@@ -338,7 +338,7 @@  static inline bool trace_probe_has_single_file(struct trace_probe *tp)
 }
 
 int trace_probe_init(struct trace_probe *tp, const char *event,
-		     const char *group, bool alloc_filter);
+		     const char *group, bool alloc_filter, int nargs);
 void trace_probe_cleanup(struct trace_probe *tp);
 int trace_probe_append(struct trace_probe *tp, struct trace_probe *to);
 void trace_probe_unlink(struct trace_probe *tp);
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index a84b85d8aac1..796ebcae9b38 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -337,7 +337,7 @@  alloc_trace_uprobe(const char *group, const char *event, int nargs, bool is_ret)
 	if (!tu)
 		return ERR_PTR(-ENOMEM);
 
-	ret = trace_probe_init(&tu->tp, event, group, true);
+	ret = trace_probe_init(&tu->tp, event, group, true, nargs);
 	if (ret < 0)
 		goto error;