X-Git-Url: http://git.liburcu.org/?p=lttng-modules.git;a=blobdiff_plain;f=lttng-context-vppid.c;h=cedf68043250791b14b6a9a4b2fda0e4804d302f;hp=4abf784613afebf844f9be3ed92946519dbff31f;hb=2459130397d7e7eecc44a5f06a39d65c78257eef;hpb=44252f0fd51fd4bf28926dcef525355bceb08c5f

diff --git a/lttng-context-vppid.c b/lttng-context-vppid.c
index 4abf7846..cedf6804 100644
--- a/lttng-context-vppid.c
+++ b/lttng-context-vppid.c
@@ -1,27 +1,27 @@
-/*
- * (C) Copyright	2009-2011 -
- * 		Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+/* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only)
+ *
+ * lttng-context-vppid.c
  *
  * LTTng vPPID context.
  *
- * Dual LGPL v2.1/GPL v2 license.
+ * Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  */
 
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/sched.h>
 #include <linux/syscalls.h>
-#include "ltt-events.h"
-#include "wrapper/ringbuffer/frontend_types.h"
-#include "wrapper/vmalloc.h"
-#include "ltt-tracer.h"
+#include <lttng-events.h>
+#include <ringbuffer/frontend_types.h>
+#include <wrapper/vmalloc.h>
+#include <lttng-tracer.h>
 
 static
 size_t vppid_get_size(size_t offset)
 {
 	size_t size = 0;
 
-	size += lib_ring_buffer_align(offset, ltt_alignof(pid_t));
+	size += lib_ring_buffer_align(offset, lttng_alignof(pid_t));
 	size += sizeof(pid_t);
 	return size;
 }
@@ -29,17 +29,66 @@ size_t vppid_get_size(size_t offset)
 static
 void vppid_record(struct lttng_ctx_field *field,
 		  struct lib_ring_buffer_ctx *ctx,
-		  struct ltt_channel *chan)
+		  struct lttng_channel *chan)
 {
+	struct task_struct *parent;
 	pid_t vppid;
 
+	/*
+	 * 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();
-	vppid = task_tgid_vnr(current->real_parent);
+	parent = rcu_dereference(current->real_parent);
+	if (!current->nsproxy)
+		vppid = 0;
+	else
+		vppid = task_tgid_vnr(parent);
 	rcu_read_unlock();
-	lib_ring_buffer_align_ctx(ctx, ltt_alignof(vppid));
+	lib_ring_buffer_align_ctx(ctx, lttng_alignof(vppid));
 	chan->ops->event_write(ctx, &vppid, sizeof(vppid));
 }
 
+static
+void vppid_get_value(struct lttng_ctx_field *field,
+		struct lttng_probe_ctx *lttng_probe_ctx,
+		union lttng_ctx_value *value)
+{
+	struct task_struct *parent;
+	pid_t vppid;
+
+	/*
+	 * 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 (!current->nsproxy)
+		vppid = 0;
+	else
+		vppid = task_tgid_vnr(parent);
+	rcu_read_unlock();
+	value->s64 = vppid;
+}
+
 int lttng_add_vppid_to_ctx(struct lttng_ctx **ctx)
 {
 	struct lttng_ctx_field *field;
@@ -53,19 +102,17 @@ int lttng_add_vppid_to_ctx(struct lttng_ctx **ctx)
 	}
 	field->event_field.name = "vppid";
 	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 = ltt_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.reverse_byte_order = 0;
-	field->event_field.type.u.basic.integer.base = 10;
-	field->event_field.type.u.basic.integer.encoding = lttng_encode_none;
+	field->event_field.type.u.integer.size = sizeof(pid_t) * CHAR_BIT;
+	field->event_field.type.u.integer.alignment = lttng_alignof(pid_t) * CHAR_BIT;
+	field->event_field.type.u.integer.signedness = lttng_is_signed_type(pid_t);
+	field->event_field.type.u.integer.reverse_byte_order = 0;
+	field->event_field.type.u.integer.base = 10;
+	field->event_field.type.u.integer.encoding = lttng_encode_none;
 	field->get_size = vppid_get_size;
 	field->record = vppid_record;
-	wrapper_vmalloc_sync_all();
+	field->get_value = vppid_get_value;
+	lttng_context_update(*ctx);
+	wrapper_vmalloc_sync_mappings();
 	return 0;
 }
 EXPORT_SYMBOL_GPL(lttng_add_vppid_to_ctx);
-
-MODULE_LICENSE("GPL and additional rights");
-MODULE_AUTHOR("Mathieu Desnoyers");
-MODULE_DESCRIPTION("Linux Trace Toolkit vPPID Context");