X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=lttng-context-vppid.c;h=06377a3098ff7f72b992f0c9848f693fbc10f7dc;hb=ff1a474fed6f77325f191583f7f555dd458ad8fa;hp=3d55fc5d6a09750f23bb08561e9f8d9725ffb75e;hpb=886d51a3d7ed5fa6b41d7f19b3e14ae6c535a44c;p=lttng-modules.git

diff --git a/lttng-context-vppid.c b/lttng-context-vppid.c
index 3d55fc5d..06377a30 100644
--- a/lttng-context-vppid.c
+++ b/lttng-context-vppid.c
@@ -48,11 +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);