X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=ltt-debugfs-abi.c;h=37cccfa35f472f0b43b9aff9693f959dc8680f8a;hb=d0255731fe93baede90f26d19aa4388403973554;hp=41774e4356a70cbede41747b5067ffd67c64d262;hpb=d7b6f1973af6171e7dde50d6a6aa6beafd3162b7;p=lttng-modules.git

diff --git a/ltt-debugfs-abi.c b/ltt-debugfs-abi.c
index 41774e43..37cccfa3 100644
--- a/ltt-debugfs-abi.c
+++ b/ltt-debugfs-abi.c
@@ -20,17 +20,23 @@
  *     - Takes an instrumentation source as parameter
  *       - e.g. tracepoints, dynamic_probes...
  *     - Takes instrumentation source specific arguments.
+ *
+ * Dual LGPL v2.1/GPL v2 license.
  */
 
 #include <linux/module.h>
 #include <linux/debugfs.h>
+#include <linux/proc_fs.h>
 #include <linux/anon_inodes.h>
 #include <linux/file.h>
 #include <linux/uaccess.h>
 #include <linux/slab.h>
-#include <linux/ringbuffer/vfs.h>
+#include "wrapper/vmalloc.h"	/* for wrapper_vmalloc_sync_all() */
+#include "wrapper/ringbuffer/vfs.h"
+#include "wrapper/poll.h"
 #include "ltt-debugfs-abi.h"
 #include "ltt-events.h"
+#include "ltt-tracer.h"
 
 /*
  * This is LTTng's own personal way to create a system call as an external
@@ -38,11 +44,23 @@
  */
 
 static struct dentry *lttng_dentry;
+static struct proc_dir_entry *lttng_proc_dentry;
 static const struct file_operations lttng_fops;
 static const struct file_operations lttng_session_fops;
 static const struct file_operations lttng_channel_fops;
+static const struct file_operations lttng_metadata_fops;
 static const struct file_operations lttng_event_fops;
 
+/*
+ * Teardown management: opened file descriptors keep a refcount on the module,
+ * so it can only exit when all file descriptors are closed.
+ */
+
+enum channel_type {
+	PER_CPU_CHANNEL,
+	METADATA_CHANNEL,
+};
+
 static
 int lttng_abi_create_session(void)
 {
@@ -76,6 +94,101 @@ fd_error:
 	return ret;
 }
 
+static
+int lttng_abi_tracepoint_list(void)
+{
+	struct file *tracepoint_list_file;
+	int file_fd, ret;
+
+	file_fd = get_unused_fd();
+	if (file_fd < 0) {
+		ret = file_fd;
+		goto fd_error;
+	}
+
+	tracepoint_list_file = anon_inode_getfile("[lttng_session]",
+					  &lttng_tracepoint_list_fops,
+					  NULL, O_RDWR);
+	if (IS_ERR(tracepoint_list_file)) {
+		ret = PTR_ERR(tracepoint_list_file);
+		goto file_error;
+	}
+	ret = lttng_tracepoint_list_fops.open(NULL, tracepoint_list_file);
+	if (ret < 0)
+		goto open_error;
+	fd_install(file_fd, tracepoint_list_file);
+	if (file_fd < 0) {
+		ret = file_fd;
+		goto fd_error;
+	}
+	return file_fd;
+
+open_error:
+	fput(tracepoint_list_file);
+file_error:
+	put_unused_fd(file_fd);
+fd_error:
+	return ret;
+}
+
+static
+long lttng_abi_tracer_version(struct file *file, 
+	struct lttng_kernel_tracer_version __user *uversion_param)
+{
+	struct lttng_kernel_tracer_version v;
+
+	v.version = LTTNG_VERSION;
+	v.patchlevel = LTTNG_PATCHLEVEL;
+	v.sublevel = LTTNG_SUBLEVEL;
+
+	if (copy_to_user(uversion_param, &v, sizeof(v)))
+		return -EFAULT;
+	return 0;
+}
+
+static
+long lttng_abi_add_context(struct file *file,
+	struct lttng_kernel_context __user *ucontext_param,
+	struct lttng_ctx **ctx, struct ltt_session *session)
+{
+	struct lttng_kernel_context context_param;
+
+	if (session->been_active)
+		return -EPERM;
+
+	if (copy_from_user(&context_param, ucontext_param, sizeof(context_param)))
+		return -EFAULT;
+
+	switch (context_param.ctx) {
+	case LTTNG_KERNEL_CONTEXT_PID:
+		return lttng_add_pid_to_ctx(ctx);
+	case LTTNG_KERNEL_CONTEXT_PRIO:
+		return lttng_add_prio_to_ctx(ctx);
+	case LTTNG_KERNEL_CONTEXT_NICE:
+		return lttng_add_nice_to_ctx(ctx);
+	case LTTNG_KERNEL_CONTEXT_VPID:
+		return lttng_add_vpid_to_ctx(ctx);
+	case LTTNG_KERNEL_CONTEXT_TID:
+		return lttng_add_tid_to_ctx(ctx);
+	case LTTNG_KERNEL_CONTEXT_VTID:
+		return lttng_add_vtid_to_ctx(ctx);
+	case LTTNG_KERNEL_CONTEXT_PPID:
+		return lttng_add_ppid_to_ctx(ctx);
+	case LTTNG_KERNEL_CONTEXT_VPPID:
+		return lttng_add_vppid_to_ctx(ctx);
+	case LTTNG_KERNEL_CONTEXT_PERF_COUNTER:
+		context_param.u.perf_counter.name[LTTNG_SYM_NAME_LEN - 1] = '\0';
+		return lttng_add_perf_counter_to_ctx(context_param.u.perf_counter.type,
+				context_param.u.perf_counter.config,
+				context_param.u.perf_counter.name,
+				ctx);
+	case LTTNG_KERNEL_CONTEXT_PROCNAME:
+		return lttng_add_procname_to_ctx(ctx);
+	default:
+		return -EINVAL;
+	}
+}
+
 /**
  *	lttng_ioctl - lttng syscall through ioctl
  *
@@ -84,8 +197,14 @@ fd_error:
  *	@arg: command arg
  *
  *	This ioctl implements lttng commands:
- *	LTTNG_SESSION
+ *	LTTNG_KERNEL_SESSION
  *		Returns a LTTng trace session file descriptor
+ *	LTTNG_KERNEL_TRACER_VERSION
+ *		Returns the LTTng kernel tracer version
+ *	LTTNG_KERNEL_TRACEPOINT_LIST
+ *		Returns a file descriptor listing available tracepoints
+ *	LTTNG_KERNEL_WAIT_QUIESCENT
+ *		Returns after all previously running probes have completed
  *
  * The returned session will be deleted when its file descriptor is closed.
  */
@@ -93,27 +212,84 @@ static
 long lttng_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
 	switch (cmd) {
-	case LTTNG_SESSION:
+	case LTTNG_KERNEL_SESSION:
 		return lttng_abi_create_session();
+	case LTTNG_KERNEL_TRACER_VERSION:
+		return lttng_abi_tracer_version(file,
+				(struct lttng_kernel_tracer_version __user *) arg);
+	case LTTNG_KERNEL_TRACEPOINT_LIST:
+		return lttng_abi_tracepoint_list();
+	case LTTNG_KERNEL_WAIT_QUIESCENT:
+		synchronize_trace();
+		return 0;
+	case LTTNG_KERNEL_CALIBRATE:
+	{
+		struct lttng_kernel_calibrate __user *ucalibrate =
+			(struct lttng_kernel_calibrate __user *) arg;
+		struct lttng_kernel_calibrate calibrate;
+		int ret;
+
+		if (copy_from_user(&calibrate, ucalibrate, sizeof(calibrate)))
+			return -EFAULT;
+		ret = lttng_calibrate(&calibrate);
+		if (copy_to_user(ucalibrate, &calibrate, sizeof(calibrate)))
+			return -EFAULT;
+		return ret;
+	}
 	default:
 		return -ENOIOCTLCMD;
 	}
 }
 
 static const struct file_operations lttng_fops = {
+	.owner = THIS_MODULE,
 	.unlocked_ioctl = lttng_ioctl,
 #ifdef CONFIG_COMPAT
 	.compat_ioctl = lttng_ioctl,
 #endif
 };
 
+/*
+ * We tolerate no failure in this function (if one happens, we print a dmesg
+ * error, but cannot return any error, because the channel information is
+ * invariant.
+ */
+static
+void lttng_metadata_create_events(struct file *channel_file)
+{
+	struct ltt_channel *channel = channel_file->private_data;
+	static struct lttng_kernel_event metadata_params = {
+		.instrumentation = LTTNG_KERNEL_TRACEPOINT,
+		.name = "lttng_metadata",
+	};
+	struct ltt_event *event;
+
+	/*
+	 * We tolerate no failure path after event creation. It will stay
+	 * invariant for the rest of the session.
+	 */
+	event = ltt_event_create(channel, &metadata_params, NULL, NULL);
+	if (!event) {
+		goto create_error;
+	}
+	return;
+
+create_error:
+	WARN_ON(1);
+	return;		/* not allowed to return error */
+}
+
+static
 int lttng_abi_create_channel(struct file *session_file,
-			     struct lttng_channel __user *uchan_param)
+			     struct lttng_kernel_channel __user *uchan_param,
+			     enum channel_type channel_type)
 {
 	struct ltt_session *session = session_file->private_data;
+	const struct file_operations *fops = NULL;
+	const char *transport_name;
 	struct ltt_channel *chan;
 	struct file *chan_file;
-	struct lttng_channel chan_param;
+	struct lttng_kernel_channel chan_param;
 	int chan_fd;
 	int ret = 0;
 
@@ -124,18 +300,51 @@ int lttng_abi_create_channel(struct file *session_file,
 		ret = chan_fd;
 		goto fd_error;
 	}
+	switch (channel_type) {
+	case PER_CPU_CHANNEL:
+		fops = &lttng_channel_fops;
+		break;
+	case METADATA_CHANNEL:
+		fops = &lttng_metadata_fops;
+		break;
+	}
+		
 	chan_file = anon_inode_getfile("[lttng_channel]",
-				       &lttng_channel_fops,
+				       fops,
 				       NULL, O_RDWR);
 	if (IS_ERR(chan_file)) {
 		ret = PTR_ERR(chan_file);
 		goto file_error;
 	}
+	switch (channel_type) {
+	case PER_CPU_CHANNEL:
+		if (chan_param.output == LTTNG_KERNEL_SPLICE) {
+			transport_name = chan_param.overwrite ?
+				"relay-overwrite" : "relay-discard";
+		} else if (chan_param.output == LTTNG_KERNEL_MMAP) {
+			transport_name = chan_param.overwrite ?
+				"relay-overwrite-mmap" : "relay-discard-mmap";
+		} else {
+			return -EINVAL;
+		}
+		break;
+	case METADATA_CHANNEL:
+		if (chan_param.output == LTTNG_KERNEL_SPLICE)
+			transport_name = "relay-metadata";
+		else if (chan_param.output == LTTNG_KERNEL_MMAP)
+			transport_name = "relay-metadata-mmap";
+		else
+			return -EINVAL;
+		break;
+	default:
+		transport_name = "<unknown>";
+		break;
+	}
 	/*
 	 * We tolerate no failure path after channel creation. It will stay
 	 * invariant for the rest of the session.
 	 */
-	chan = ltt_channel_create(session, chan_param.overwrite, NULL,
+	chan = ltt_channel_create(session, transport_name, NULL,
 				  chan_param.subbuf_size,
 				  chan_param.num_subbuf,
 				  chan_param.switch_timer_interval,
@@ -147,6 +356,11 @@ int lttng_abi_create_channel(struct file *session_file,
 	chan->file = chan_file;
 	chan_file->private_data = chan;
 	fd_install(chan_fd, chan_file);
+	if (channel_type == METADATA_CHANNEL) {
+		session->metadata = chan;
+		lttng_metadata_create_events(chan_file);
+	}
+
 	/* The channel created holds a reference on the session */
 	atomic_long_inc(&session_file->f_count);
 
@@ -168,8 +382,14 @@ fd_error:
  *	@arg: command arg
  *
  *	This ioctl implements lttng commands:
- *	LTTNG_CHANNEL
+ *	LTTNG_KERNEL_CHANNEL
  *		Returns a LTTng channel file descriptor
+ *	LTTNG_KERNEL_ENABLE
+ *		Enables tracing for a session (weak enable)
+ *	LTTNG_KERNEL_DISABLE
+ *		Disables tracing for a session (strong disable)
+ *	LTTNG_KERNEL_METADATA
+ *		Returns a LTTng metadata file descriptor
  *
  * The returned channel will be deleted when its file descriptor is closed.
  */
@@ -179,12 +399,20 @@ long lttng_session_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 	struct ltt_session *session = file->private_data;
 
 	switch (cmd) {
-	case LTTNG_CHANNEL:
-		return lttng_abi_create_channel(file, (struct lttng_channel __user *)arg);
-	case LTTNG_SESSION_START:
-		return ltt_session_start(session);
-	case LTTNG_SESSION_STOP:
-		return ltt_session_stop(session);
+	case LTTNG_KERNEL_CHANNEL:
+		return lttng_abi_create_channel(file,
+				(struct lttng_kernel_channel __user *) arg,
+				PER_CPU_CHANNEL);
+	case LTTNG_KERNEL_SESSION_START:
+	case LTTNG_KERNEL_ENABLE:
+		return ltt_session_enable(session);
+	case LTTNG_KERNEL_SESSION_STOP:
+	case LTTNG_KERNEL_DISABLE:
+		return ltt_session_disable(session);
+	case LTTNG_KERNEL_METADATA:
+		return lttng_abi_create_channel(file,
+				(struct lttng_kernel_channel __user *) arg,
+				METADATA_CHANNEL);
 	default:
 		return -ENOIOCTLCMD;
 	}
@@ -209,6 +437,7 @@ int lttng_session_release(struct inode *inode, struct file *file)
 }
 
 static const struct file_operations lttng_session_fops = {
+	.owner = THIS_MODULE,
 	.release = lttng_session_release,
 	.unlocked_ioctl = lttng_session_ioctl,
 #ifdef CONFIG_COMPAT
@@ -263,59 +492,70 @@ fd_error:
 
 static
 int lttng_abi_create_event(struct file *channel_file,
-			   struct lttng_event __user *uevent_param)
+			   struct lttng_kernel_event __user *uevent_param)
 {
 	struct ltt_channel *channel = channel_file->private_data;
 	struct ltt_event *event;
-	char *event_name;
-	struct lttng_event event_param;
+	struct lttng_kernel_event event_param;
 	int event_fd, ret;
 	struct file *event_file;
-	void *probe;
 
 	if (copy_from_user(&event_param, uevent_param, sizeof(event_param)))
 		return -EFAULT;
-	event_name = kmalloc(PATH_MAX, GFP_KERNEL);
-	if (!event_name)
-		return -ENOMEM;
-	if (strncpy_from_user(event_name, uevent_param->name, PATH_MAX) < 0) {
-		ret = -EFAULT;
-		goto name_error;
-	}
-	event_name[PATH_MAX - 1] = '\0';
-
-	probe = ltt_probe_get(event_name);
-	if (!probe) {
-		ret = -ENOENT;
-		goto probe_error;
-	}
-	event_fd = get_unused_fd();
-	if (event_fd < 0) {
-		ret = event_fd;
-		goto fd_error;
-	}
-	event_file = anon_inode_getfile("[lttng_event]",
-					&lttng_event_fops,
-					NULL, O_RDWR);
-	if (IS_ERR(event_file)) {
-		ret = PTR_ERR(event_file);
-		goto file_error;
+	event_param.name[LTTNG_SYM_NAME_LEN - 1] = '\0';
+	switch (event_param.instrumentation) {
+	case LTTNG_KERNEL_KRETPROBE:
+		event_param.u.kretprobe.symbol_name[LTTNG_SYM_NAME_LEN - 1] = '\0';
+		break;
+	case LTTNG_KERNEL_KPROBE:
+		event_param.u.kprobe.symbol_name[LTTNG_SYM_NAME_LEN - 1] = '\0';
+		break;
+	case LTTNG_KERNEL_FUNCTION:
+		event_param.u.ftrace.symbol_name[LTTNG_SYM_NAME_LEN - 1] = '\0';
+		break;
+	default:
+		break;
 	}
-	/*
-	 * We tolerate no failure path after event creation. It will stay
-	 * invariant for the rest of the session.
-	 */
-	event = ltt_event_create(channel, event_name, event_param.itype,
-				 probe, NULL);
-	if (!event) {
-		goto event_error;
-		ret = -EEXIST;
+	switch (event_param.instrumentation) {
+	default:
+		event_fd = get_unused_fd();
+		if (event_fd < 0) {
+			ret = event_fd;
+			goto fd_error;
+		}
+		event_file = anon_inode_getfile("[lttng_event]",
+						&lttng_event_fops,
+						NULL, O_RDWR);
+		if (IS_ERR(event_file)) {
+			ret = PTR_ERR(event_file);
+			goto file_error;
+		}
+		/*
+		 * We tolerate no failure path after event creation. It
+		 * will stay invariant for the rest of the session.
+		 */
+		event = ltt_event_create(channel, &event_param, NULL, NULL);
+		if (!event) {
+			ret = -EINVAL;
+			goto event_error;
+		}
+		event_file->private_data = event;
+		fd_install(event_fd, event_file);
+		/* The event holds a reference on the channel */
+		atomic_long_inc(&channel_file->f_count);
+		break;
+	case LTTNG_KERNEL_SYSCALL:
+		/*
+		 * Only all-syscall tracing supported for now.
+		 */
+		if (event_param.name[0] != '\0')
+			return -EINVAL;
+		ret = lttng_syscalls_register(channel, NULL);
+		if (ret)
+			goto fd_error;
+		event_fd = 0;
+		break;
 	}
-	event_file->private_data = event;
-	fd_install(event_fd, event_file);
-	/* The event holds a reference on the channel */
-	atomic_long_inc(&channel_file->f_count);
-	kfree(event_name);
 	return event_fd;
 
 event_error:
@@ -323,10 +563,6 @@ event_error:
 file_error:
 	put_unused_fd(event_fd);
 fd_error:
-	ltt_probe_put(probe);
-probe_error:
-name_error:
-	kfree(event_name);
 	return ret;
 }
 
@@ -338,30 +574,67 @@ name_error:
  *	@arg: command arg
  *
  *	This ioctl implements lttng commands:
- *      LTTNG_STREAM
+ *      LTTNG_KERNEL_STREAM
  *              Returns an event stream file descriptor or failure.
  *              (typically, one event stream records events from one CPU)
- *	LTTNG_EVENT
+ *	LTTNG_KERNEL_EVENT
  *		Returns an event file descriptor or failure.
+ *	LTTNG_KERNEL_CONTEXT
+ *		Prepend a context field to each event in the channel
+ *	LTTNG_KERNEL_ENABLE
+ *		Enable recording for events in this channel (weak enable)
+ *	LTTNG_KERNEL_DISABLE
+ *		Disable recording for events in this channel (strong disable)
  *
- * The returned session will be deleted when its file descriptor is closed.
  * Channel and event file descriptors also hold a reference on the session.
  */
 static
 long lttng_channel_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
+	struct ltt_channel *channel = file->private_data;
+
 	switch (cmd) {
-	case LTTNG_STREAM:
+	case LTTNG_KERNEL_STREAM:
+		return lttng_abi_open_stream(file);
+	case LTTNG_KERNEL_EVENT:
+		return lttng_abi_create_event(file, (struct lttng_kernel_event __user *) arg);
+	case LTTNG_KERNEL_CONTEXT:
+		return lttng_abi_add_context(file,
+				(struct lttng_kernel_context __user *) arg,
+				&channel->ctx, channel->session);
+	case LTTNG_KERNEL_ENABLE:
+		return ltt_channel_enable(channel);
+	case LTTNG_KERNEL_DISABLE:
+		return ltt_channel_disable(channel);
+	default:
+		return -ENOIOCTLCMD;
+	}
+}
+
+/**
+ *	lttng_metadata_ioctl - lttng syscall through ioctl
+ *
+ *	@file: the file
+ *	@cmd: the command
+ *	@arg: command arg
+ *
+ *	This ioctl implements lttng commands:
+ *      LTTNG_KERNEL_STREAM
+ *              Returns an event stream file descriptor or failure.
+ *
+ * Channel and event file descriptors also hold a reference on the session.
+ */
+static
+long lttng_metadata_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	switch (cmd) {
+	case LTTNG_KERNEL_STREAM:
 		return lttng_abi_open_stream(file);
-	case LTTNG_EVENT:
-		return lttng_abi_create_event(file, (struct lttng_event __user *)arg);
 	default:
 		return -ENOIOCTLCMD;
 	}
 }
 
-/* TODO: poll */
-#if 0
 /**
  *	lttng_channel_poll - lttng stream addition/removal monitoring
  *
@@ -375,18 +648,20 @@ unsigned int lttng_channel_poll(struct file *file, poll_table *wait)
 
 	if (file->f_mode & FMODE_READ) {
 		poll_wait_set_exclusive(wait);
-		poll_wait(file, &channel->notify_wait, wait);
+		poll_wait(file, channel->ops->get_hp_wait_queue(channel->chan),
+			  wait);
 
-		/* TODO: identify when the channel is being finalized. */
-		if (finalized)
+		if (channel->ops->is_disabled(channel->chan))
+			return POLLERR;
+		if (channel->ops->is_finalized(channel->chan))
 			return POLLHUP;
-		else
+		if (channel->ops->buffer_has_read_closed_stream(channel->chan))
 			return POLLIN | POLLRDNORM;
+		return 0;
 	}
 	return mask;
 
 }
-#endif //0
 
 static
 int lttng_channel_release(struct inode *inode, struct file *file)
@@ -399,17 +674,58 @@ int lttng_channel_release(struct inode *inode, struct file *file)
 }
 
 static const struct file_operations lttng_channel_fops = {
+	.owner = THIS_MODULE,
 	.release = lttng_channel_release,
-/* TODO */
-#if 0
 	.poll = lttng_channel_poll,
-#endif //0
 	.unlocked_ioctl = lttng_channel_ioctl,
 #ifdef CONFIG_COMPAT
 	.compat_ioctl = lttng_channel_ioctl,
 #endif
 };
 
+static const struct file_operations lttng_metadata_fops = {
+	.owner = THIS_MODULE,
+	.release = lttng_channel_release,
+	.unlocked_ioctl = lttng_metadata_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl = lttng_metadata_ioctl,
+#endif
+};
+
+/**
+ *	lttng_event_ioctl - lttng syscall through ioctl
+ *
+ *	@file: the file
+ *	@cmd: the command
+ *	@arg: command arg
+ *
+ *	This ioctl implements lttng commands:
+ *	LTTNG_KERNEL_CONTEXT
+ *		Prepend a context field to each record of this event
+ *	LTTNG_KERNEL_ENABLE
+ *		Enable recording for this event (weak enable)
+ *	LTTNG_KERNEL_DISABLE
+ *		Disable recording for this event (strong disable)
+ */
+static
+long lttng_event_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	struct ltt_event *event = file->private_data;
+
+	switch (cmd) {
+	case LTTNG_KERNEL_CONTEXT:
+		return lttng_abi_add_context(file,
+				(struct lttng_kernel_context __user *) arg,
+				&event->ctx, event->chan->session);
+	case LTTNG_KERNEL_ENABLE:
+		return ltt_event_enable(event);
+	case LTTNG_KERNEL_DISABLE:
+		return ltt_event_disable(event);
+	default:
+		return -ENOIOCTLCMD;
+	}
+}
+
 static
 int lttng_event_release(struct inode *inode, struct file *file)
 {
@@ -422,16 +738,28 @@ int lttng_event_release(struct inode *inode, struct file *file)
 
 /* TODO: filter control ioctl */
 static const struct file_operations lttng_event_fops = {
+	.owner = THIS_MODULE,
 	.release = lttng_event_release,
+	.unlocked_ioctl = lttng_event_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl = lttng_event_ioctl,
+#endif
 };
 
 int __init ltt_debugfs_abi_init(void)
 {
 	int ret = 0;
 
+	wrapper_vmalloc_sync_all();
 	lttng_dentry = debugfs_create_file("lttng", S_IWUSR, NULL, NULL,
-					   &lttng_fops);
-	if (IS_ERR(lttng_dentry) || !lttng_dentry) {
+					&lttng_fops);
+	if (IS_ERR(lttng_dentry))
+		lttng_dentry = NULL;
+
+	lttng_proc_dentry = proc_create_data("lttng", S_IWUSR, NULL,
+					&lttng_fops, NULL);
+	
+	if (!lttng_dentry && !lttng_proc_dentry) {
 		printk(KERN_ERR "Error creating LTTng control file\n");
 		ret = -ENOMEM;
 		goto error;
@@ -442,5 +770,8 @@ error:
 
 void __exit ltt_debugfs_abi_exit(void)
 {
-	debugfs_remove(lttng_dentry);
+	if (lttng_dentry)
+		debugfs_remove(lttng_dentry);
+	if (lttng_proc_dentry)
+		remove_proc_entry("lttng", NULL);
 }