Merge tag 'trace-v4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing updates from Steven Rostedt:

 - Rework of the kprobe/uprobe and synthetic events to consolidate all
   the dynamic event code. This will make changes in the future easier.

 - Partial rewrite of the function graph tracing infrastructure. This
   will allow for multiple users of hooking onto functions to get the
   callback (return) of the function. This is the ground work for having
   kprobes and function graph tracer using one code base.

 - Clean up of the histogram code that will facilitate adding more
   features to the histograms in the future.

 - Addition of str_has_prefix() and a few use cases. There currently is
   a similar function strstart() that is used in a few places, but only
   returns a bool and not a length. These instances will be removed in
   the future to use str_has_prefix() instead.

 - A few other various clean ups as well.

* tag 'trace-v4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (57 commits)
  tracing: Use the return of str_has_prefix() to remove open coded numbers
  tracing: Have the historgram use the result of str_has_prefix() for len of prefix
  tracing: Use str_has_prefix() instead of using fixed sizes
  tracing: Use str_has_prefix() helper for histogram code
  string.h: Add str_has_prefix() helper function
  tracing: Make function ‘ftrace_exports’ static
  tracing: Simplify printf'ing in seq_print_sym
  tracing: Avoid -Wformat-nonliteral warning
  tracing: Merge seq_print_sym_short() and seq_print_sym_offset()
  tracing: Add hist trigger comments for variable-related fields
  tracing: Remove hist trigger synth_var_refs
  tracing: Use hist trigger's var_ref array to destroy var_refs
  tracing: Remove open-coding of hist trigger var_ref management
  tracing: Use var_refs[] for hist trigger reference checking
  tracing: Change strlen to sizeof for hist trigger static strings
  tracing: Remove unnecessary hist trigger struct field
  tracing: Fix ftrace_graph_get_ret_stack() to use task and not current
  seq_buf: Use size_t for len in seq_buf_puts()
  seq_buf: Make seq_buf_puts() null-terminate the buffer
  arm64: Use ftrace_graph_get_ret_stack() instead of curr_ret_stack
  ...

1 files changed, 143 insertions, 158 deletions

diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index 31ea48eceda1..e335576b9411 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -7,6 +7,7 @@
  */
 #define pr_fmt(fmt)	"trace_kprobe: " fmt
 
+#include <linux/ctype.h>
 #include <linux/module.h>
 #include <linux/uaccess.h>
 #include <linux/uprobes.h>
@@ -14,6 +15,7 @@
 #include <linux/string.h>
 #include <linux/rculist.h>
 
+#include "trace_dynevent.h"
 #include "trace_probe.h"
 #include "trace_probe_tmpl.h"
 
@@ -37,11 +39,26 @@ struct trace_uprobe_filter {
 	struct list_head	perf_events;
 };
 
+static int trace_uprobe_create(int argc, const char **argv);
+static int trace_uprobe_show(struct seq_file *m, struct dyn_event *ev);
+static int trace_uprobe_release(struct dyn_event *ev);
+static bool trace_uprobe_is_busy(struct dyn_event *ev);
+static bool trace_uprobe_match(const char *system, const char *event,
+			       struct dyn_event *ev);
+
+static struct dyn_event_operations trace_uprobe_ops = {
+	.create = trace_uprobe_create,
+	.show = trace_uprobe_show,
+	.is_busy = trace_uprobe_is_busy,
+	.free = trace_uprobe_release,
+	.match = trace_uprobe_match,
+};
+
 /*
  * uprobe event core functions
  */
 struct trace_uprobe {
-	struct list_head		list;
+	struct dyn_event		devent;
 	struct trace_uprobe_filter	filter;
 	struct uprobe_consumer		consumer;
 	struct path			path;
@@ -53,6 +70,25 @@ struct trace_uprobe {
 	struct trace_probe		tp;
 };
 
+static bool is_trace_uprobe(struct dyn_event *ev)
+{
+	return ev->ops == &trace_uprobe_ops;
+}
+
+static struct trace_uprobe *to_trace_uprobe(struct dyn_event *ev)
+{
+	return container_of(ev, struct trace_uprobe, devent);
+}
+
+/**
+ * for_each_trace_uprobe - iterate over the trace_uprobe list
+ * @pos:	the struct trace_uprobe * for each entry
+ * @dpos:	the struct dyn_event * to use as a loop cursor
+ */
+#define for_each_trace_uprobe(pos, dpos)	\
+	for_each_dyn_event(dpos)		\
+		if (is_trace_uprobe(dpos) && (pos = to_trace_uprobe(dpos)))
+
 #define SIZEOF_TRACE_UPROBE(n)				\
 	(offsetof(struct trace_uprobe, tp.args) +	\
 	(sizeof(struct probe_arg) * (n)))
@@ -60,9 +96,6 @@ struct trace_uprobe {
 static int register_uprobe_event(struct trace_uprobe *tu);
 static int unregister_uprobe_event(struct trace_uprobe *tu);
 
-static DEFINE_MUTEX(uprobe_lock);
-static LIST_HEAD(uprobe_list);
-
 struct uprobe_dispatch_data {
 	struct trace_uprobe	*tu;
 	unsigned long		bp_addr;
@@ -209,6 +242,22 @@ static inline bool is_ret_probe(struct trace_uprobe *tu)
 	return tu->consumer.ret_handler != NULL;
 }
 
+static bool trace_uprobe_is_busy(struct dyn_event *ev)
+{
+	struct trace_uprobe *tu = to_trace_uprobe(ev);
+
+	return trace_probe_is_enabled(&tu->tp);
+}
+
+static bool trace_uprobe_match(const char *system, const char *event,
+			       struct dyn_event *ev)
+{
+	struct trace_uprobe *tu = to_trace_uprobe(ev);
+
+	return strcmp(trace_event_name(&tu->tp.call), event) == 0 &&
+		(!system || strcmp(tu->tp.call.class->system, system) == 0);
+}
+
 /*
  * Allocate new trace_uprobe and initialize it (including uprobes).
  */
@@ -236,7 +285,7 @@ alloc_trace_uprobe(const char *group, const char *event, int nargs, bool is_ret)
 	if (!tu->tp.class.system)
 		goto error;
 
-	INIT_LIST_HEAD(&tu->list);
+	dyn_event_init(&tu->devent, &trace_uprobe_ops);
 	INIT_LIST_HEAD(&tu->tp.files);
 	tu->consumer.handler = uprobe_dispatcher;
 	if (is_ret)
@@ -255,6 +304,9 @@ static void free_trace_uprobe(struct trace_uprobe *tu)
 {
 	int i;
 
+	if (!tu)
+		return;
+
 	for (i = 0; i < tu->tp.nr_args; i++)
 		traceprobe_free_probe_arg(&tu->tp.args[i]);
 
@@ -267,9 +319,10 @@ static void free_trace_uprobe(struct trace_uprobe *tu)
 
 static struct trace_uprobe *find_probe_event(const char *event, const char *group)
 {
+	struct dyn_event *pos;
 	struct trace_uprobe *tu;
 
-	list_for_each_entry(tu, &uprobe_list, list)
+	for_each_trace_uprobe(tu, pos)
 		if (strcmp(trace_event_name(&tu->tp.call), event) == 0 &&
 		    strcmp(tu->tp.call.class->system, group) == 0)
 			return tu;
@@ -277,7 +330,7 @@ static struct trace_uprobe *find_probe_event(const char *event, const char *grou
 	return NULL;
 }
 
-/* Unregister a trace_uprobe and probe_event: call with locking uprobe_lock */
+/* Unregister a trace_uprobe and probe_event */
 static int unregister_trace_uprobe(struct trace_uprobe *tu)
 {
 	int ret;
@@ -286,7 +339,7 @@ static int unregister_trace_uprobe(struct trace_uprobe *tu)
 	if (ret)
 		return ret;
 
-	list_del(&tu->list);
+	dyn_event_remove(&tu->devent);
 	free_trace_uprobe(tu);
 	return 0;
 }
@@ -302,13 +355,14 @@ static int unregister_trace_uprobe(struct trace_uprobe *tu)
  */
 static struct trace_uprobe *find_old_trace_uprobe(struct trace_uprobe *new)
 {
+	struct dyn_event *pos;
 	struct trace_uprobe *tmp, *old = NULL;
 	struct inode *new_inode = d_real_inode(new->path.dentry);
 
 	old = find_probe_event(trace_event_name(&new->tp.call),
 				new->tp.call.class->system);
 
-	list_for_each_entry(tmp, &uprobe_list, list) {
+	for_each_trace_uprobe(tmp, pos) {
 		if ((old ? old != tmp : true) &&
 		    new_inode == d_real_inode(tmp->path.dentry) &&
 		    new->offset == tmp->offset &&
@@ -326,7 +380,7 @@ static int register_trace_uprobe(struct trace_uprobe *tu)
 	struct trace_uprobe *old_tu;
 	int ret;
 
-	mutex_lock(&uprobe_lock);
+	mutex_lock(&event_mutex);
 
 	/* register as an event */
 	old_tu = find_old_trace_uprobe(tu);
@@ -348,10 +402,10 @@ static int register_trace_uprobe(struct trace_uprobe *tu)
 		goto end;
 	}
 
-	list_add_tail(&tu->list, &uprobe_list);
+	dyn_event_add(&tu->devent);
 
 end:
-	mutex_unlock(&uprobe_lock);
+	mutex_unlock(&event_mutex);
 
 	return ret;
 }
@@ -362,91 +416,49 @@ end:
  *
  *  - Remove uprobe: -:[GRP/]EVENT
  */
-static int create_trace_uprobe(int argc, char **argv)
+static int trace_uprobe_create(int argc, const char **argv)
 {
 	struct trace_uprobe *tu;
-	char *arg, *event, *group, *filename, *rctr, *rctr_end;
+	const char *event = NULL, *group = UPROBE_EVENT_SYSTEM;
+	char *arg, *filename, *rctr, *rctr_end, *tmp;
 	char buf[MAX_EVENT_NAME_LEN];
 	struct path path;
 	unsigned long offset, ref_ctr_offset;
-	bool is_delete, is_return;
+	bool is_return = false;
 	int i, ret;
 
 	ret = 0;
-	is_delete = false;
-	is_return = false;
-	event = NULL;
-	group = NULL;
 	ref_ctr_offset = 0;
 
 	/* argc must be >= 1 */
-	if (argv[0][0] == '-')
-		is_delete = true;
-	else if (argv[0][0] == 'r')
+	if (argv[0][0] == 'r')
 		is_return = true;
-	else if (argv[0][0] != 'p') {
-		pr_info("Probe definition must be started with 'p', 'r' or '-'.\n");
-		return -EINVAL;
-	}
+	else if (argv[0][0] != 'p' || argc < 2)
+		return -ECANCELED;
 
-	if (argv[0][1] == ':') {
+	if (argv[0][1] == ':')
 		event = &argv[0][2];
-		arg = strchr(event, '/');
-
-		if (arg) {
-			group = event;
-			event = arg + 1;
-			event[-1] = '\0';
-
-			if (strlen(group) == 0) {
-				pr_info("Group name is not specified\n");
-				return -EINVAL;
-			}
-		}
-		if (strlen(event) == 0) {
-			pr_info("Event name is not specified\n");
-			return -EINVAL;
-		}
-	}
-	if (!group)
-		group = UPROBE_EVENT_SYSTEM;
 
-	if (is_delete) {
-		int ret;
+	if (!strchr(argv[1], '/'))
+		return -ECANCELED;
 
-		if (!event) {
-			pr_info("Delete command needs an event name.\n");
-			return -EINVAL;
-		}
-		mutex_lock(&uprobe_lock);
-		tu = find_probe_event(event, group);
-
-		if (!tu) {
-			mutex_unlock(&uprobe_lock);
-			pr_info("Event %s/%s doesn't exist.\n", group, event);
-			return -ENOENT;
-		}
-		/* delete an event */
-		ret = unregister_trace_uprobe(tu);
-		mutex_unlock(&uprobe_lock);
-		return ret;
-	}
+	filename = kstrdup(argv[1], GFP_KERNEL);
+	if (!filename)
+		return -ENOMEM;
 
-	if (argc < 2) {
-		pr_info("Probe point is not specified.\n");
-		return -EINVAL;
-	}
 	/* Find the last occurrence, in case the path contains ':' too. */
-	arg = strrchr(argv[1], ':');
-	if (!arg)
-		return -EINVAL;
+	arg = strrchr(filename, ':');
+	if (!arg || !isdigit(arg[1])) {
+		kfree(filename);
+		return -ECANCELED;
+	}
 
 	*arg++ = '\0';
-	filename = argv[1];
 	ret = kern_path(filename, LOOKUP_FOLLOW, &path);
-	if (ret)
+	if (ret) {
+		kfree(filename);
 		return ret;
-
+	}
 	if (!d_is_reg(path.dentry)) {
 		ret = -EINVAL;
 		goto fail_address_parse;
@@ -480,7 +492,11 @@ static int create_trace_uprobe(int argc, char **argv)
 	argv += 2;
 
 	/* setup a probe */
-	if (!event) {
+	if (event) {
+		ret = traceprobe_parse_event_name(&event, &group, buf);
+		if (ret)
+			goto fail_address_parse;
+	} else {
 		char *tail;
 		char *ptr;
 
@@ -508,60 +524,21 @@ static int create_trace_uprobe(int argc, char **argv)
 	tu->offset = offset;
 	tu->ref_ctr_offset = ref_ctr_offset;
 	tu->path = path;
-	tu->filename = kstrdup(filename, GFP_KERNEL);
-
-	if (!tu->filename) {
-		pr_info("Failed to allocate filename.\n");
-		ret = -ENOMEM;
-		goto error;
-	}
+	tu->filename = filename;
 
 	/* parse arguments */
-	ret = 0;
 	for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
-		struct probe_arg *parg = &tu->tp.args[i];
-
-		/* Increment count for freeing args in error case */
-		tu->tp.nr_args++;
-
-		/* Parse argument name */
-		arg = strchr(argv[i], '=');
-		if (arg) {
-			*arg++ = '\0';
-			parg->name = kstrdup(argv[i], GFP_KERNEL);
-		} else {
-			arg = argv[i];
-			/* If argument name is omitted, set "argN" */
-			snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
-			parg->name = kstrdup(buf, GFP_KERNEL);
-		}
-
-		if (!parg->name) {
-			pr_info("Failed to allocate argument[%d] name.\n", i);
+		tmp = kstrdup(argv[i], GFP_KERNEL);
+		if (!tmp) {
 			ret = -ENOMEM;
 			goto error;
 		}
 
-		if (!is_good_name(parg->name)) {
-			pr_info("Invalid argument[%d] name: %s\n", i, parg->name);
-			ret = -EINVAL;
-			goto error;
-		}
-
-		if (traceprobe_conflict_field_name(parg->name, tu->tp.args, i)) {
-			pr_info("Argument[%d] name '%s' conflicts with "
-				"another field.\n", i, argv[i]);
-			ret = -EINVAL;
-			goto error;
-		}
-
-		/* Parse fetch argument */
-		ret = traceprobe_parse_probe_arg(arg, &tu->tp.size, parg,
+		ret = traceprobe_parse_probe_arg(&tu->tp, i, tmp,
 					is_return ? TPARG_FL_RETURN : 0);
-		if (ret) {
-			pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
+		kfree(tmp);
+		if (ret)
 			goto error;
-		}
 	}
 
 	ret = register_trace_uprobe(tu);
@@ -575,48 +552,35 @@ error:
 
 fail_address_parse:
 	path_put(&path);
+	kfree(filename);
 
 	pr_info("Failed to parse address or file.\n");
 
 	return ret;
 }
 
-static int cleanup_all_probes(void)
+static int create_or_delete_trace_uprobe(int argc, char **argv)
 {
-	struct trace_uprobe *tu;
-	int ret = 0;
+	int ret;
 
-	mutex_lock(&uprobe_lock);
-	while (!list_empty(&uprobe_list)) {
-		tu = list_entry(uprobe_list.next, struct trace_uprobe, list);
-		ret = unregister_trace_uprobe(tu);
-		if (ret)
-			break;
-	}
-	mutex_unlock(&uprobe_lock);
-	return ret;
-}
+	if (argv[0][0] == '-')
+		return dyn_event_release(argc, argv, &trace_uprobe_ops);
 
-/* Probes listing interfaces */
-static void *probes_seq_start(struct seq_file *m, loff_t *pos)
-{
-	mutex_lock(&uprobe_lock);
-	return seq_list_start(&uprobe_list, *pos);
+	ret = trace_uprobe_create(argc, (const char **)argv);
+	return ret == -ECANCELED ? -EINVAL : ret;
 }
 
-static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
+static int trace_uprobe_release(struct dyn_event *ev)
 {
-	return seq_list_next(v, &uprobe_list, pos);
-}
+	struct trace_uprobe *tu = to_trace_uprobe(ev);
 
-static void probes_seq_stop(struct seq_file *m, void *v)
-{
-	mutex_unlock(&uprobe_lock);
+	return unregister_trace_uprobe(tu);
 }
 
-static int probes_seq_show(struct seq_file *m, void *v)
+/* Probes listing interfaces */
+static int trace_uprobe_show(struct seq_file *m, struct dyn_event *ev)
 {
-	struct trace_uprobe *tu = v;
+	struct trace_uprobe *tu = to_trace_uprobe(ev);
 	char c = is_ret_probe(tu) ? 'r' : 'p';
 	int i;
 
@@ -634,11 +598,21 @@ static int probes_seq_show(struct seq_file *m, void *v)
 	return 0;
 }
 
+static int probes_seq_show(struct seq_file *m, void *v)
+{
+	struct dyn_event *ev = v;
+
+	if (!is_trace_uprobe(ev))
+		return 0;
+
+	return trace_uprobe_show(m, ev);
+}
+
 static const struct seq_operations probes_seq_op = {
-	.start	= probes_seq_start,
-	.next	= probes_seq_next,
-	.stop	= probes_seq_stop,
-	.show	= probes_seq_show
+	.start  = dyn_event_seq_start,
+	.next   = dyn_event_seq_next,
+	.stop   = dyn_event_seq_stop,
+	.show   = probes_seq_show
 };
 
 static int probes_open(struct inode *inode, struct file *file)
@@ -646,7 +620,7 @@ static int probes_open(struct inode *inode, struct file *file)
 	int ret;
 
 	if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
-		ret = cleanup_all_probes();
+		ret = dyn_events_release_all(&trace_uprobe_ops);
 		if (ret)
 			return ret;
 	}
@@ -657,7 +631,8 @@ static int probes_open(struct inode *inode, struct file *file)
 static ssize_t probes_write(struct file *file, const char __user *buffer,
 			    size_t count, loff_t *ppos)
 {
-	return trace_parse_run_command(file, buffer, count, ppos, create_trace_uprobe);
+	return trace_parse_run_command(file, buffer, count, ppos,
+					create_or_delete_trace_uprobe);
 }
 
 static const struct file_operations uprobe_events_ops = {
@@ -672,17 +647,22 @@ static const struct file_operations uprobe_events_ops = {
 /* Probes profiling interfaces */
 static int probes_profile_seq_show(struct seq_file *m, void *v)
 {
-	struct trace_uprobe *tu = v;
+	struct dyn_event *ev = v;
+	struct trace_uprobe *tu;
 
+	if (!is_trace_uprobe(ev))
+		return 0;
+
+	tu = to_trace_uprobe(ev);
 	seq_printf(m, "  %s %-44s %15lu\n", tu->filename,
 			trace_event_name(&tu->tp.call), tu->nhit);
 	return 0;
 }
 
 static const struct seq_operations profile_seq_op = {
-	.start	= probes_seq_start,
-	.next	= probes_seq_next,
-	.stop	= probes_seq_stop,
+	.start  = dyn_event_seq_start,
+	.next   = dyn_event_seq_next,
+	.stop   = dyn_event_seq_stop,
 	.show	= probes_profile_seq_show
 };
 
@@ -1384,7 +1364,7 @@ create_local_trace_uprobe(char *name, unsigned long offs,
 	}
 
 	/*
-	 * local trace_kprobes are not added to probe_list, so they are never
+	 * local trace_kprobes are not added to dyn_event, so they are never
 	 * searched in find_trace_kprobe(). Therefore, there is no concern of
 	 * duplicated name "DUMMY_EVENT" here.
 	 */
@@ -1432,6 +1412,11 @@ void destroy_local_trace_uprobe(struct trace_event_call *event_call)
 static __init int init_uprobe_trace(void)
 {
 	struct dentry *d_tracer;
+	int ret;
+
+	ret = dyn_event_register(&trace_uprobe_ops);
+	if (ret)
+		return ret;
 
 	d_tracer = tracing_init_dentry();
 	if (IS_ERR(d_tracer))