Fix ftrace integration

[lttng-modules.git] / probes / lttng-ftrace.c

diff --git a/probes/lttng-ftrace.c b/probes/lttng-ftrace.c
index f583ab6ee9afd2c1d25cd23a657345f07e082137..5b4cf2e7e153c0318e2ca8d485489bd46340e7aa 100644 (file)
--- a/probes/lttng-ftrace.c
+++ b/probes/lttng-ftrace.c
@@ -38,7 +38,7 @@ void lttng_ftrace_handler(unsigned long ip, unsigned long parent_ip, void **data
                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;
        payload.ip = ip;
@@ -118,7 +118,7 @@ int lttng_ftrace_register(const char *name,
        if (ret)
                goto error;
 
-       event->u.ftrace.symbol_name = kstrdup(name, GFP_KERNEL);
+       event->u.ftrace.symbol_name = kstrdup(symbol_name, GFP_KERNEL);
        if (!event->u.ftrace.symbol_name)
                goto name_error;
 
@@ -127,7 +127,7 @@ int lttng_ftrace_register(const char *name,
 
        ret = wrapper_register_ftrace_function_probe(event->u.ftrace.symbol_name,
                        &lttng_ftrace_ops, event);
-       if (ret)
+       if (ret < 0)
                goto register_error;
        return 0;
 
@@ -146,13 +146,12 @@ void lttng_ftrace_unregister(struct ltt_event *event)
        wrapper_unregister_ftrace_function_probe(event->u.ftrace.symbol_name,
                        &lttng_ftrace_ops, event);
        kfree(event->u.ftrace.symbol_name);
-       kfree(desc->fields);
+       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();
@@ -160,6 +159,15 @@ int lttng_ftrace_init(void)
 }
 module_init(lttng_ftrace_init)
 
+/*
+ * Ftrace takes care of waiting for a grace period (RCU sched) at probe
+ * unregistration, and disables preemption around probe call.
+ */
+void lttng_ftrace_exit(void)
+{
+}
+module_exit(lttng_ftrace_exit)
+
 MODULE_LICENSE("GPL and additional rights");
 MODULE_AUTHOR("Mathieu Desnoyers");
 MODULE_DESCRIPTION("Linux Trace Toolkit Ftrace Support");