X-Git-Url: http://git.lttng.org./?a=blobdiff_plain;f=lttng-context-prio.c;h=1ee3a54daf2c33b331a1a3d97e247478b8a65679;hb=91a951f3eff49196d889935778fab43306ab31a8;hp=a62685f7dc7d7fe578a592097b1b02642fb881ed;hpb=8fefc8a2d93a06a032c7983cf621ab3fb0c2acde;p=lttng-modules.git

diff --git a/lttng-context-prio.c b/lttng-context-prio.c
index a62685f7..1ee3a54d 100644
--- a/lttng-context-prio.c
+++ b/lttng-context-prio.c
@@ -13,8 +13,22 @@
 #include "ltt-events.h"
 #include "wrapper/ringbuffer/frontend_types.h"
 #include "wrapper/vmalloc.h"
+#include "wrapper/kallsyms.h"
 #include "ltt-tracer.h"
 
+static
+int (*wrapper_task_prio_sym)(struct task_struct *t);
+
+int wrapper_task_prio_init(void)
+{
+	wrapper_task_prio_sym = (void *) kallsyms_lookup_funcptr("task_prio");
+	if (!wrapper_task_prio_sym) {
+		printk(KERN_WARNING "LTTng: task_prio symbol lookup failed.\n");
+		return -EINVAL;
+	}
+	return 0;
+}
+
 static
 size_t prio_get_size(size_t offset)
 {
@@ -42,9 +56,19 @@ int lttng_add_prio_to_ctx(struct lttng_ctx **ctx)
 	struct lttng_ctx_field *field;
 	int ret;
 
+	if (!wrapper_task_prio_sym) {
+		ret = wrapper_task_prio_init();
+		if (ret)
+			return ret;
+	}
+
 	field = lttng_append_context(ctx);
 	if (!field)
-		return ret;
+		return -ENOMEM;
+	if (lttng_find_context(*ctx, "prio")) {
+		lttng_remove_context_field(ctx, field);
+		return -EEXIST;
+	}
 	field->event_field.name = "prio";
 	field->event_field.type.atype = atype_integer;
 	field->event_field.type.u.basic.integer.size = sizeof(int) * CHAR_BIT;