1 files changed, 127 insertions, 65 deletions

diff --git a/kernel/marker.c b/kernel/marker.c
index e9c6b2bc940..ea54f264786 100644
--- a/kernel/marker.c
+++ b/kernel/marker.c
@@ -43,6 +43,7 @@ static DEFINE_MUTEX(markers_mutex);
  */
 #define MARKER_HASH_BITS 6
 #define MARKER_TABLE_SIZE (1 << MARKER_HASH_BITS)
+static struct hlist_head marker_table[MARKER_TABLE_SIZE];
 
 /*
  * Note about RCU :
@@ -64,11 +65,10 @@ struct marker_entry {
 	void *oldptr;
 	int rcu_pending;
 	unsigned char ptype:1;
+	unsigned char format_allocated:1;
 	char name[0];	/* Contains name'\0'format'\0' */
 };
 
-static struct hlist_head marker_table[MARKER_TABLE_SIZE];
-
 /**
  * __mark_empty_function - Empty probe callback
  * @probe_private: probe private data
@@ -81,7 +81,7 @@ static struct hlist_head marker_table[MARKER_TABLE_SIZE];
  * though the function pointer change and the marker enabling are two distinct
  * operations that modifies the execution flow of preemptible code.
  */
-void __mark_empty_function(void *probe_private, void *call_private,
+notrace void __mark_empty_function(void *probe_private, void *call_private,
 	const char *fmt, va_list *args)
 {
 }
@@ -97,7 +97,8 @@ EXPORT_SYMBOL_GPL(__mark_empty_function);
  * need to put a full smp_rmb() in this branch. This is why we do not use
  * rcu_dereference() for the pointer read.
  */
-void marker_probe_cb(const struct marker *mdata, void *call_private, ...)
+notrace void marker_probe_cb(const struct marker *mdata,
+		void *call_private, ...)
 {
 	va_list args;
 	char ptype;
@@ -107,7 +108,7 @@ void marker_probe_cb(const struct marker *mdata, void *call_private, ...)
 	 * sure the teardown of the callbacks can be done correctly when they
 	 * are in modules and they insure RCU read coherency.
 	 */
-	rcu_read_lock_sched();
+	rcu_read_lock_sched_notrace();
 	ptype = mdata->ptype;
 	if (likely(!ptype)) {
 		marker_probe_func *func;
@@ -145,7 +146,7 @@ void marker_probe_cb(const struct marker *mdata, void *call_private, ...)
 			va_end(args);
 		}
 	}
-	rcu_read_unlock_sched();
+	rcu_read_unlock_sched_notrace();
 }
 EXPORT_SYMBOL_GPL(marker_probe_cb);
 
@@ -157,12 +158,13 @@ EXPORT_SYMBOL_GPL(marker_probe_cb);
  *
  * Should be connected to markers "MARK_NOARGS".
  */
-void marker_probe_cb_noarg(const struct marker *mdata, void *call_private, ...)
+static notrace void marker_probe_cb_noarg(const struct marker *mdata,
+		void *call_private, ...)
 {
 	va_list args;	/* not initialized */
 	char ptype;
 
-	rcu_read_lock_sched();
+	rcu_read_lock_sched_notrace();
 	ptype = mdata->ptype;
 	if (likely(!ptype)) {
 		marker_probe_func *func;
@@ -195,9 +197,8 @@ void marker_probe_cb_noarg(const struct marker *mdata, void *call_private, ...)
 			multi[i].func(multi[i].probe_private, call_private,
 				mdata->format, &args);
 	}
-	rcu_read_unlock_sched();
+	rcu_read_unlock_sched_notrace();
 }
-EXPORT_SYMBOL_GPL(marker_probe_cb_noarg);
 
 static void free_old_closure(struct rcu_head *head)
 {
@@ -416,6 +417,7 @@ static struct marker_entry *add_marker(const char *name, const char *format)
 	e->single.probe_private = NULL;
 	e->multi = NULL;
 	e->ptype = 0;
+	e->format_allocated = 0;
 	e->refcount = 0;
 	e->rcu_pending = 0;
 	hlist_add_head(&e->hlist, head);
@@ -447,6 +449,8 @@ static int remove_marker(const char *name)
 	if (e->single.func != __mark_empty_function)
 		return -EBUSY;
 	hlist_del(&e->hlist);
+	if (e->format_allocated)
+		kfree(e->format);
 	/* Make sure the call_rcu has been executed */
 	if (e->rcu_pending)
 		rcu_barrier_sched();
@@ -457,57 +461,34 @@ static int remove_marker(const char *name)
 /*
  * Set the mark_entry format to the format found in the element.
  */
-static int marker_set_format(struct marker_entry **entry, const char *format)
+static int marker_set_format(struct marker_entry *entry, const char *format)
 {
-	struct marker_entry *e;
-	size_t name_len = strlen((*entry)->name) + 1;
-	size_t format_len = strlen(format) + 1;
-
-
-	e = kmalloc(sizeof(struct marker_entry) + name_len + format_len,
-			GFP_KERNEL);
-	if (!e)
+	entry->format = kstrdup(format, GFP_KERNEL);
+	if (!entry->format)
 		return -ENOMEM;
-	memcpy(&e->name[0], (*entry)->name, name_len);
-	e->format = &e->name[name_len];
-	memcpy(e->format, format, format_len);
-	if (strcmp(e->format, MARK_NOARGS) == 0)
-		e->call = marker_probe_cb_noarg;
-	else
-		e->call = marker_probe_cb;
-	e->single = (*entry)->single;
-	e->multi = (*entry)->multi;
-	e->ptype = (*entry)->ptype;
-	e->refcount = (*entry)->refcount;
-	e->rcu_pending = 0;
-	hlist_add_before(&e->hlist, &(*entry)->hlist);
-	hlist_del(&(*entry)->hlist);
-	/* Make sure the call_rcu has been executed */
-	if ((*entry)->rcu_pending)
-		rcu_barrier_sched();
-	kfree(*entry);
-	*entry = e;
+	entry->format_allocated = 1;
+
 	trace_mark(core_marker_format, "name %s format %s",
-			e->name, e->format);
+			entry->name, entry->format);
 	return 0;
 }
 
 /*
  * Sets the probe callback corresponding to one marker.
  */
-static int set_marker(struct marker_entry **entry, struct marker *elem,
+static int set_marker(struct marker_entry *entry, struct marker *elem,
 		int active)
 {
-	int ret;
-	WARN_ON(strcmp((*entry)->name, elem->name) != 0);
+	int ret = 0;
+	WARN_ON(strcmp(entry->name, elem->name) != 0);
 
-	if ((*entry)->format) {
-		if (strcmp((*entry)->format, elem->format) != 0) {
+	if (entry->format) {
+		if (strcmp(entry->format, elem->format) != 0) {
 			printk(KERN_NOTICE
 				"Format mismatch for probe %s "
 				"(%s), marker (%s)\n",
-				(*entry)->name,
-				(*entry)->format,
+				entry->name,
+				entry->format,
 				elem->format);
 			return -EPERM;
 		}
@@ -523,37 +504,67 @@ static int set_marker(struct marker_entry **entry, struct marker *elem,
 	 * pass from a "safe" callback (with argument) to an "unsafe"
 	 * callback (does not set arguments).
 	 */
-	elem->call = (*entry)->call;
+	elem->call = entry->call;
 	/*
 	 * Sanity check :
 	 * We only update the single probe private data when the ptr is
 	 * set to a _non_ single probe! (0 -> 1 and N -> 1, N != 1)
 	 */
 	WARN_ON(elem->single.func != __mark_empty_function
-		&& elem->single.probe_private
-		!= (*entry)->single.probe_private &&
-		!elem->ptype);
-	elem->single.probe_private = (*entry)->single.probe_private;
+		&& elem->single.probe_private != entry->single.probe_private
+		&& !elem->ptype);
+	elem->single.probe_private = entry->single.probe_private;
 	/*
 	 * Make sure the private data is valid when we update the
 	 * single probe ptr.
 	 */
 	smp_wmb();
-	elem->single.func = (*entry)->single.func;
+	elem->single.func = entry->single.func;
 	/*
 	 * We also make sure that the new probe callbacks array is consistent
 	 * before setting a pointer to it.
 	 */
-	rcu_assign_pointer(elem->multi, (*entry)->multi);
+	rcu_assign_pointer(elem->multi, entry->multi);
 	/*
 	 * Update the function or multi probe array pointer before setting the
 	 * ptype.
 	 */
 	smp_wmb();
-	elem->ptype = (*entry)->ptype;
+	elem->ptype = entry->ptype;
+
+	if (elem->tp_name && (active ^ elem->state)) {
+		WARN_ON(!elem->tp_cb);
+		/*
+		 * It is ok to directly call the probe registration because type
+		 * checking has been done in the __trace_mark_tp() macro.
+		 */
+
+		if (active) {
+			/*
+			 * try_module_get should always succeed because we hold
+			 * lock_module() to get the tp_cb address.
+			 */
+			ret = try_module_get(__module_text_address(
+				(unsigned long)elem->tp_cb));
+			BUG_ON(!ret);
+			ret = tracepoint_probe_register_noupdate(
+				elem->tp_name,
+				elem->tp_cb);
+		} else {
+			ret = tracepoint_probe_unregister_noupdate(
+				elem->tp_name,
+				elem->tp_cb);
+			/*
+			 * tracepoint_probe_update_all() must be called
+			 * before the module containing tp_cb is unloaded.
+			 */
+			module_put(__module_text_address(
+				(unsigned long)elem->tp_cb));
+		}
+	}
 	elem->state = active;
 
-	return 0;
+	return ret;
 }
 
 /*
@@ -564,7 +575,24 @@ static int set_marker(struct marker_entry **entry, struct marker *elem,
  */
 static void disable_marker(struct marker *elem)
 {
+	int ret;
+
 	/* leave "call" as is. It is known statically. */
+	if (elem->tp_name && elem->state) {
+		WARN_ON(!elem->tp_cb);
+		/*
+		 * It is ok to directly call the probe registration because type
+		 * checking has been done in the __trace_mark_tp() macro.
+		 */
+		ret = tracepoint_probe_unregister_noupdate(elem->tp_name,
+			elem->tp_cb);
+		WARN_ON(ret);
+		/*
+		 * tracepoint_probe_update_all() must be called
+		 * before the module containing tp_cb is unloaded.
+		 */
+		module_put(__module_text_address((unsigned long)elem->tp_cb));
+	}
 	elem->state = 0;
 	elem->single.func = __mark_empty_function;
 	/* Update the function before setting the ptype */
@@ -594,8 +622,7 @@ void marker_update_probe_range(struct marker *begin,
 	for (iter = begin; iter < end; iter++) {
 		mark_entry = get_marker(iter->name);
 		if (mark_entry) {
-			set_marker(&mark_entry, iter,
-					!!mark_entry->refcount);
+			set_marker(mark_entry, iter, !!mark_entry->refcount);
 			/*
 			 * ignore error, continue
 			 */
@@ -629,6 +656,7 @@ static void marker_update_probes(void)
 	marker_update_probe_range(__start___markers, __stop___markers);
 	/* Markers in modules. */
 	module_update_markers();
+	tracepoint_probe_update_all();
 }
 
 /**
@@ -657,7 +685,7 @@ int marker_probe_register(const char *name, const char *format,
 			ret = PTR_ERR(entry);
 	} else if (format) {
 		if (!entry->format)
-			ret = marker_set_format(&entry, format);
+			ret = marker_set_format(entry, format);
 		else if (strcmp(entry->format, format))
 			ret = -EPERM;
 	}
@@ -676,10 +704,11 @@ int marker_probe_register(const char *name, const char *format,
 		goto end;
 	}
 	mutex_unlock(&markers_mutex);
-	marker_update_probes();		/* may update entry */
+	marker_update_probes();
 	mutex_lock(&markers_mutex);
 	entry = get_marker(name);
-	WARN_ON(!entry);
+	if (!entry)
+		goto end;
 	if (entry->rcu_pending)
 		rcu_barrier_sched();
 	entry->oldptr = old;
@@ -720,7 +749,7 @@ int marker_probe_unregister(const char *name,
 		rcu_barrier_sched();
 	old = marker_entry_remove_probe(entry, probe, probe_private);
 	mutex_unlock(&markers_mutex);
-	marker_update_probes();		/* may update entry */
+	marker_update_probes();
 	mutex_lock(&markers_mutex);
 	entry = get_marker(name);
 	if (!entry)
@@ -801,10 +830,11 @@ int marker_probe_unregister_private_data(marker_probe_func *probe,
 		rcu_barrier_sched();
 	old = marker_entry_remove_probe(entry, NULL, probe_private);
 	mutex_unlock(&markers_mutex);
-	marker_update_probes();		/* may update entry */
+	marker_update_probes();
 	mutex_lock(&markers_mutex);
 	entry = get_marker_from_private_data(probe, probe_private);
-	WARN_ON(!entry);
+	if (!entry)
+		goto end;
 	if (entry->rcu_pending)
 		rcu_barrier_sched();
 	entry->oldptr = old;
@@ -848,8 +878,6 @@ void *marker_get_private_data(const char *name, marker_probe_func *probe,
 			if (!e->ptype) {
 				if (num == 0 && e->single.func == probe)
 					return e->single.probe_private;
-				else
-					break;
 			} else {
 				struct marker_probe_closure *closure;
 				int match = 0;
@@ -861,8 +889,42 @@ void *marker_get_private_data(const char *name, marker_probe_func *probe,
 						return closure[i].probe_private;
 				}
 			}
+			break;
 		}
 	}
 	return ERR_PTR(-ENOENT);
 }
 EXPORT_SYMBOL_GPL(marker_get_private_data);
+
+#ifdef CONFIG_MODULES
+
+int marker_module_notify(struct notifier_block *self,
+			 unsigned long val, void *data)
+{
+	struct module *mod = data;
+
+	switch (val) {
+	case MODULE_STATE_COMING:
+		marker_update_probe_range(mod->markers,
+			mod->markers + mod->num_markers);
+		break;
+	case MODULE_STATE_GOING:
+		marker_update_probe_range(mod->markers,
+			mod->markers + mod->num_markers);
+		break;
+	}
+	return 0;
+}
+
+struct notifier_block marker_module_nb = {
+	.notifier_call = marker_module_notify,
+	.priority = 0,
+};
+
+static int init_markers(void)
+{
+	return register_module_notifier(&marker_module_nb);
+}
+__initcall(init_markers);
+
+#endif /* CONFIG_MODULES */