X-Git-Url: http://git.lttng.org./?a=blobdiff_plain;f=probes%2Flttng-ftrace.c;h=7c4fc9f55d78f5fc98898cd45af8a630b37e90ae;hb=1c726b25f42c14020fbafdaa5cbb2c3eb1644b53;hp=4b7be18336c07d8b8eecd1f745a64da00a6ebc7a;hpb=e0a7a7c4a6a88a60ae40baeb4f4656f58175993a;p=lttng-modules.git

diff --git a/probes/lttng-ftrace.c b/probes/lttng-ftrace.c
index 4b7be183..7c4fc9f5 100644
--- a/probes/lttng-ftrace.c
+++ b/probes/lttng-ftrace.c
@@ -7,15 +7,23 @@
  * Dual LGPL v2.1/GPL v2 license.
  */
 
+/*
+ * Ftrace function tracer does not seem to provide synchronization between probe
+ * teardown and callback execution. Therefore, we make this module permanently
+ * loaded (unloadable).
+ */
+
 #include <linux/module.h>
 #include <linux/ftrace.h>
 #include <linux/slab.h>
 #include "../ltt-events.h"
 #include "../wrapper/ringbuffer/frontend_types.h"
+#include "../wrapper/ftrace.h"
+#include "../wrapper/vmalloc.h"
 #include "../ltt-tracer.h"
 
 static
-int lttng_ftrace_handler(unsigned long ip, unsigned long parent_ip, void **data)
+void lttng_ftrace_handler(unsigned long ip, unsigned long parent_ip, void **data)
 {
 	struct ltt_event *event = *data;
 	struct ltt_channel *chan = event->chan;
@@ -27,18 +35,18 @@ int lttng_ftrace_handler(unsigned long ip, unsigned long parent_ip, void **data)
 	int ret;
 
 	if (!ACCESS_ONCE(chan->session->active))
-		return 0;
+		return;
 	lib_ring_buffer_ctx_init(&ctx, chan->chan, NULL,
 				 sizeof(payload), ltt_alignof(payload), -1);
-	ret = chan->ops->event_reserve(&ctx);
+	ret = chan->ops->event_reserve(&ctx, event->id);
 	if (ret < 0)
-		return 0;
+		return;
 	payload.ip = ip;
 	payload.parent_ip = parent_ip;
 	lib_ring_buffer_align_ctx(&ctx, ltt_alignof(payload));
 	chan->ops->event_write(&ctx, &payload, sizeof(payload));
 	chan->ops->event_commit(&ctx);
-	return 0;
+	return;
 }
 
 /*
@@ -62,10 +70,14 @@ int lttng_create_ftrace_event(const char *name, struct ltt_event *event)
 	desc->nr_fields = 2;
 	desc->fields = fields =
 		kzalloc(2 * sizeof(struct lttng_event_field), GFP_KERNEL);
+	if (!desc->fields) {
+		ret = -ENOMEM;
+		goto error_fields;
+	}
 	fields[0].name = "ip";
 	fields[0].type.atype = atype_integer;
-	fields[0].type.u.basic.integer.size = sizeof(unsigned long);
-	fields[0].type.u.basic.integer.alignment = ltt_alignof(unsigned long);
+	fields[0].type.u.basic.integer.size = sizeof(unsigned long) * CHAR_BIT;
+	fields[0].type.u.basic.integer.alignment = ltt_alignof(unsigned long) * CHAR_BIT;
 	fields[0].type.u.basic.integer.signedness = 0;
 	fields[0].type.u.basic.integer.reverse_byte_order = 0;
 	fields[0].type.u.basic.integer.base = 16;
@@ -73,8 +85,8 @@ int lttng_create_ftrace_event(const char *name, struct ltt_event *event)
 
 	fields[1].name = "parent_ip";
 	fields[1].type.atype = atype_integer;
-	fields[1].type.u.basic.integer.size = sizeof(unsigned long);
-	fields[1].type.u.basic.integer.alignment = ltt_alignof(unsigned long);
+	fields[1].type.u.basic.integer.size = sizeof(unsigned long) * CHAR_BIT;
+	fields[1].type.u.basic.integer.alignment = ltt_alignof(unsigned long) * CHAR_BIT;
 	fields[1].type.u.basic.integer.signedness = 0;
 	fields[1].type.u.basic.integer.reverse_byte_order = 0;
 	fields[1].type.u.basic.integer.base = 16;
@@ -84,6 +96,8 @@ int lttng_create_ftrace_event(const char *name, struct ltt_event *event)
 
 	return 0;
 
+error_fields:
+	kfree(desc->name);
 error_str:
 	kfree(desc);
 	return ret;
@@ -108,7 +122,10 @@ int lttng_ftrace_register(const char *name,
 	if (!event->u.ftrace.symbol_name)
 		goto name_error;
 
-	ret = register_ftrace_function_probe(symbol_name,
+	/* Ensure the memory we just allocated don't trigger page faults */
+	wrapper_vmalloc_sync_all();
+
+	ret = wrapper_register_ftrace_function_probe(event->u.ftrace.symbol_name,
 			&lttng_ftrace_ops, event);
 	if (ret)
 		goto register_error;
@@ -126,14 +143,23 @@ EXPORT_SYMBOL_GPL(lttng_ftrace_register);
 
 void lttng_ftrace_unregister(struct ltt_event *event)
 {
-	unregister_ftrace_function_probe(event->u.ftrace.symbol_name,
+	wrapper_unregister_ftrace_function_probe(event->u.ftrace.symbol_name,
 			&lttng_ftrace_ops, event);
 	kfree(event->u.ftrace.symbol_name);
+	kfree(event->desc->fields);
 	kfree(event->desc->name);
 	kfree(event->desc);
 }
 EXPORT_SYMBOL_GPL(lttng_ftrace_unregister);
 
+/* This module is permanent. */
+int lttng_ftrace_init(void)
+{
+	wrapper_vmalloc_sync_all();
+	return 0;
+}
+module_init(lttng_ftrace_init)
+
 MODULE_LICENSE("GPL and additional rights");
 MODULE_AUTHOR("Mathieu Desnoyers");
 MODULE_DESCRIPTION("Linux Trace Toolkit Ftrace Support");