X-Git-Url: http://git.lttng.org./?a=blobdiff_plain;f=probes%2Flttng-kprobes.c;h=784002aed09662d179a01bea12a0c4f706bbcaf4;hb=b2c4e8fb4f093e99d5e464c759f3be1f3ea4a83e;hp=9d9fb5b9a759fd6445f70478c907657736f1f082;hpb=e0a7a7c4a6a88a60ae40baeb4f4656f58175993a;p=lttng-modules.git

diff --git a/probes/lttng-kprobes.c b/probes/lttng-kprobes.c
index 9d9fb5b9..784002ae 100644
--- a/probes/lttng-kprobes.c
+++ b/probes/lttng-kprobes.c
@@ -12,6 +12,7 @@
 #include <linux/slab.h>
 #include "../ltt-events.h"
 #include "../wrapper/ringbuffer/frontend_types.h"
+#include "../wrapper/vmalloc.h"
 #include "../ltt-tracer.h"
 
 static
@@ -24,11 +25,16 @@ int lttng_kprobes_handler_pre(struct kprobe *p, struct pt_regs *regs)
 	int ret;
 	unsigned long data = (unsigned long) p->addr;
 
-	if (!ACCESS_ONCE(chan->session->active))
+	if (unlikely(!ACCESS_ONCE(chan->session->active)))
 		return 0;
-	lib_ring_buffer_ctx_init(&ctx, chan->chan, NULL, sizeof(data),
+	if (unlikely(!ACCESS_ONCE(chan->enabled)))
+		return 0;
+	if (unlikely(!ACCESS_ONCE(event->enabled)))
+		return 0;
+
+	lib_ring_buffer_ctx_init(&ctx, chan->chan, event, sizeof(data),
 				 ltt_alignof(data), -1);
-	ret = chan->ops->event_reserve(&ctx);
+	ret = chan->ops->event_reserve(&ctx, event->id);
 	if (ret < 0)
 		return 0;
 	lib_ring_buffer_align_ctx(&ctx, ltt_alignof(data));
@@ -58,18 +64,25 @@ int lttng_create_kprobe_event(const char *name, struct ltt_event *event)
 	desc->nr_fields = 1;
 	desc->fields = field =
 		kzalloc(1 * sizeof(struct lttng_event_field), GFP_KERNEL);
+	if (!field) {
+		ret = -ENOMEM;
+		goto error_field;
+	}
 	field->name = "ip";
 	field->type.atype = atype_integer;
-	field->type.u.basic.integer.size = sizeof(unsigned long);
-	field->type.u.basic.integer.alignment = ltt_alignof(unsigned long);
-	field->type.u.basic.integer.signedness = 0;
+	field->type.u.basic.integer.size = sizeof(unsigned long) * CHAR_BIT;
+	field->type.u.basic.integer.alignment = ltt_alignof(unsigned long) * CHAR_BIT;
+	field->type.u.basic.integer.signedness = is_signed_type(unsigned long);
 	field->type.u.basic.integer.reverse_byte_order = 0;
 	field->type.u.basic.integer.base = 16;
 	field->type.u.basic.integer.encoding = lttng_encode_none;
+	desc->owner = THIS_MODULE;
 	event->desc = desc;
 
 	return 0;
 
+error_field:
+	kfree(desc->name);
 error_str:
 	kfree(desc);
 	return ret;
@@ -83,24 +96,38 @@ int lttng_kprobes_register(const char *name,
 {
 	int ret;
 
+	/* Kprobes expects a NULL symbol name if unused */
+	if (symbol_name[0] == '\0')
+		symbol_name = NULL;
+
 	ret = lttng_create_kprobe_event(name, event);
 	if (ret)
 		goto error;
 	memset(&event->u.kprobe.kp, 0, sizeof(event->u.kprobe.kp));
 	event->u.kprobe.kp.pre_handler = lttng_kprobes_handler_pre;
-	event->u.kprobe.symbol_name =
-		kzalloc(LTTNG_SYM_NAME_LEN * sizeof(char),
-			GFP_KERNEL);
-	if (!event->u.kprobe.symbol_name) {
-		ret = -ENOMEM;
-		goto name_error;
+	if (symbol_name) {
+		event->u.kprobe.symbol_name =
+			kzalloc(LTTNG_SYM_NAME_LEN * sizeof(char),
+				GFP_KERNEL);
+		if (!event->u.kprobe.symbol_name) {
+			ret = -ENOMEM;
+			goto name_error;
+		}
+		memcpy(event->u.kprobe.symbol_name, symbol_name,
+		       LTTNG_SYM_NAME_LEN * sizeof(char));
+		event->u.kprobe.kp.symbol_name =
+			event->u.kprobe.symbol_name;
 	}
-	memcpy(event->u.kprobe.symbol_name, symbol_name,
-	       LTTNG_SYM_NAME_LEN * sizeof(char));
-	event->u.kprobe.kp.symbol_name =
-		event->u.kprobe.symbol_name;
 	event->u.kprobe.kp.offset = offset;
-	event->u.kprobe.kp.addr = (void *) addr;
+	event->u.kprobe.kp.addr = (void *) (unsigned long) addr;
+
+	/*
+	 * Ensure the memory we just allocated don't trigger page faults.
+	 * Well.. kprobes itself puts the page fault handler on the blacklist,
+	 * but we can never be too careful.
+	 */
+	wrapper_vmalloc_sync_all();
+
 	ret = register_kprobe(&event->u.kprobe.kp);
 	if (ret)
 		goto register_error;
@@ -109,6 +136,7 @@ int lttng_kprobes_register(const char *name,
 register_error:
 	kfree(event->u.kprobe.symbol_name);
 name_error:
+	kfree(event->desc->fields);
 	kfree(event->desc->name);
 	kfree(event->desc);
 error:
@@ -119,11 +147,17 @@ EXPORT_SYMBOL_GPL(lttng_kprobes_register);
 void lttng_kprobes_unregister(struct ltt_event *event)
 {
 	unregister_kprobe(&event->u.kprobe.kp);
+}
+EXPORT_SYMBOL_GPL(lttng_kprobes_unregister);
+
+void lttng_kprobes_destroy_private(struct ltt_event *event)
+{
 	kfree(event->u.kprobe.symbol_name);
+	kfree(event->desc->fields);
 	kfree(event->desc->name);
 	kfree(event->desc);
 }
-EXPORT_SYMBOL_GPL(lttng_kprobes_unregister);
+EXPORT_SYMBOL_GPL(lttng_kprobes_destroy_private);
 
 MODULE_LICENSE("GPL and additional rights");
 MODULE_AUTHOR("Mathieu Desnoyers");