X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=lttng-context-vppid.c;h=e36b55523feae1df2344001e1711a29613823b83;hb=refs%2Fheads%2Fstable-2.3;hp=2fe2ffd1c1a0d02606f77f6232db27bf12797efe;hpb=a90917c3f8c4ed79117f1caa333b29a2108084ec;p=lttng-modules.git

diff --git a/lttng-context-vppid.c b/lttng-context-vppid.c
index 2fe2ffd1..e36b5552 100644
--- a/lttng-context-vppid.c
+++ b/lttng-context-vppid.c
@@ -1,10 +1,23 @@
 /*
- * (C) Copyright	2009-2011 -
- * 		Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ * lttng-context-vppid.c
  *
  * LTTng vPPID context.
  *
- * Dual LGPL v2.1/GPL v2 license.
+ * Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; only
+ * version 2.1 of the License.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 #include <linux/module.h>
@@ -35,11 +48,21 @@ void vppid_record(struct lttng_ctx_field *field,
 	pid_t vppid;
 
 	/*
-	 * nsproxy can be NULL when scheduled out of exit.
+	 * current nsproxy can be NULL when scheduled out of exit. pid_vnr uses
+	 * the current thread nsproxy to perform the lookup.
 	 */
+
+	/*
+	 * TODO: when we eventually add RCU subsystem instrumentation,
+	 * taking the rcu read lock here will trigger RCU tracing
+	 * recursively. We should modify the kernel synchronization so
+	 * it synchronizes both for RCU and RCU sched, and rely on
+	 * rcu_read_lock_sched_notrace.
+	 */
+
 	rcu_read_lock();
 	parent = rcu_dereference(current->real_parent);
-	if (!parent->nsproxy)
+	if (!current->nsproxy)
 		vppid = 0;
 	else
 		vppid = task_tgid_vnr(parent);
@@ -63,7 +86,7 @@ int lttng_add_vppid_to_ctx(struct lttng_ctx **ctx)
 	field->event_field.type.atype = atype_integer;
 	field->event_field.type.u.basic.integer.size = sizeof(pid_t) * CHAR_BIT;
 	field->event_field.type.u.basic.integer.alignment = lttng_alignof(pid_t) * CHAR_BIT;
-	field->event_field.type.u.basic.integer.signedness = is_signed_type(pid_t);
+	field->event_field.type.u.basic.integer.signedness = lttng_is_signed_type(pid_t);
 	field->event_field.type.u.basic.integer.reverse_byte_order = 0;
 	field->event_field.type.u.basic.integer.base = 10;
 	field->event_field.type.u.basic.integer.encoding = lttng_encode_none;