Merge tag 'trace-v4.18' of git://git.kernel.org/pub/scm/linux/kernel/…

…git/rostedt/linux-trace

Pull tracing updates from Steven Rostedt:
 "One new feature was added to ftrace, which is the trace_marker now
  supports triggers. For example:

    # cd /sys/kernel/debug/tracing
    # echo 'snapshot' > events/ftrace/print/trigger
    # echo 'cause snapshot' > trace_marker

  The rest of the changes are various clean ups and also one stable fix
  that was added late in the cycle"

* tag 'trace-v4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (21 commits)
  tracing: Use match_string() instead of open coding it in trace_set_options()
  branch-check: fix long->int truncation when profiling branches
  ring-buffer: Fix typo in comment
  ring-buffer: Fix a bunch of typos in comments
  tracing/selftest: Add test to test simple snapshot trigger for trace_marker
  tracing/selftest: Add test to test hist trigger between kernel event and trace_marker
  tracing/selftest: Add selftests to test trace_marker histogram triggers
  ftrace/selftest: Fix reset_trigger() to handle triggers with filters
  ftrace/selftest: Have the reset_trigger code be a bit more careful
  tracing: Document trace_marker triggers
  tracing: Allow histogram triggers to access ftrace internal events
  tracing: Prevent further users of zero size static arrays in trace events
  tracing: Have zero size length in filter logic be full string
  tracing: Add trigger file for trace_markers tracefs/ftrace/print
  tracing: Do not show filter file for ftrace internal events
  tracing: Add brackets in ftrace event dynamic arrays
  tracing: Have event_trace_init() called by trace_init_tracefs()
  tracing: Add __find_event_file() to find event files without restrictions
  tracing: Do not reference event data in post call triggers
  tracepoints: Fix the descriptions of tracepoint_probe_register{_prio}
  ...

Documentation/trace/events.rst

@@ -338,10 +338,14 @@ used for conditionally invoking triggers.
 
 The syntax for event triggers is roughly based on the syntax for
 set_ftrace_filter 'ftrace filter commands' (see the 'Filter commands'
-section of Documentation/trace/ftrace.txt), but there are major
+section of Documentation/trace/ftrace.rst), but there are major
 differences and the implementation isn't currently tied to it in any
 way, so beware about making generalizations between the two.
 
+Note: Writing into trace_marker (See Documentation/trace/ftrace.rst)
+     can also enable triggers that are written into
+     /sys/kernel/tracing/events/ftrace/print/trigger
+
 6.1 Expression syntax
 ---------------------
 

Documentation/trace/ftrace.rst

@@ -512,6 +512,11 @@ of ftrace. Here is a list of some of the key files:
 
 		trace_fd = open("trace_marker", WR_ONLY);
 
+	Note: Writing into the trace_marker file can also initiate triggers
+	      that are written into /sys/kernel/tracing/events/ftrace/print/trigger
+	      See "Event triggers" in Documentation/trace/events.rst and an
+              example in Documentation/trace/histogram.rst (Section 3.)
+
   trace_marker_raw:
 
 	This is similar to trace_marker above, but is meant for for binary data

include/linux/compiler.h

@@ -21,7 +21,7 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
 #define unlikely_notrace(x)	__builtin_expect(!!(x), 0)
 
 #define __branch_check__(x, expect, is_constant) ({			\
-			int ______r;					\
+			long ______r;					\
 			static struct ftrace_likely_data		\
 				__attribute__((__aligned__(4)))		\
 				__attribute__((section("_ftrace_annotated_branch"))) \

include/linux/ring_buffer.h

@@ -65,7 +65,7 @@ u64 ring_buffer_event_time_stamp(struct ring_buffer_event *event);
 
 /*
  * ring_buffer_discard_commit will remove an event that has not
- *   ben committed yet. If this is used, then ring_buffer_unlock_commit
+ *   been committed yet. If this is used, then ring_buffer_unlock_commit
  *   must not be called on the discarded event. This function
  *   will try to remove the event from the ring buffer completely
  *   if another event has not been written after it.

include/linux/trace_events.h

@@ -435,8 +435,7 @@ event_triggers_call(struct trace_event_file *file, void *rec,
 		    struct ring_buffer_event *event);
 extern void
 event_triggers_post_call(struct trace_event_file *file,
-			 enum event_trigger_type tt,
-			 void *rec, struct ring_buffer_event *event);
+			 enum event_trigger_type tt);
 
 bool trace_event_ignore_this_pid(struct trace_event_file *trace_file);
 

include/trace/trace_events.h

@@ -422,6 +422,7 @@ static struct trace_event_functions trace_event_type_funcs_##call = {	\
 	do {								\
 		char *type_str = #type"["__stringify(len)"]";		\
 		BUILD_BUG_ON(len > MAX_FILTER_STR_VAL);			\
+		BUILD_BUG_ON(len <= 0);					\
 		ret = trace_define_field(event_call, type_str, #item,	\
 				 offsetof(typeof(field), item),		\
 				 sizeof(field.item),			\

kernel/trace/ring_buffer.c

@@ -809,7 +809,7 @@ EXPORT_SYMBOL_GPL(ring_buffer_normalize_time_stamp);
  *
  *  You can see, it is legitimate for the previous pointer of
  *  the head (or any page) not to point back to itself. But only
- *  temporarially.
+ *  temporarily.
  */
 
 #define RB_PAGE_NORMAL		0UL
@@ -906,7 +906,7 @@ static void rb_list_head_clear(struct list_head *list)
 }
 
 /*
- * rb_head_page_dactivate - clears head page ptr (for free list)
+ * rb_head_page_deactivate - clears head page ptr (for free list)
  */
 static void
 rb_head_page_deactivate(struct ring_buffer_per_cpu *cpu_buffer)
@@ -1780,7 +1780,7 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size,
 
 		put_online_cpus();
 	} else {
-		/* Make sure this CPU has been intitialized */
+		/* Make sure this CPU has been initialized */
 		if (!cpumask_test_cpu(cpu_id, buffer->cpumask))
 			goto out;
 
@@ -2325,7 +2325,7 @@ rb_update_event(struct ring_buffer_per_cpu *cpu_buffer,
 
 	/*
 	 * If we need to add a timestamp, then we
-	 * add it to the start of the resevered space.
+	 * add it to the start of the reserved space.
 	 */
 	if (unlikely(info->add_timestamp)) {
 		bool abs = ring_buffer_time_stamp_abs(cpu_buffer->buffer);
@@ -2681,7 +2681,7 @@ trace_recursive_unlock(struct ring_buffer_per_cpu *cpu_buffer)
  * ring_buffer_nest_start - Allow to trace while nested
  * @buffer: The ring buffer to modify
  *
- * The ring buffer has a safty mechanism to prevent recursion.
+ * The ring buffer has a safety mechanism to prevent recursion.
  * But there may be a case where a trace needs to be done while
  * tracing something else. In this case, calling this function
  * will allow this function to nest within a currently active
@@ -2699,7 +2699,7 @@ void ring_buffer_nest_start(struct ring_buffer *buffer)
 	preempt_disable_notrace();
 	cpu = raw_smp_processor_id();
 	cpu_buffer = buffer->buffers[cpu];
-	/* This is the shift value for the above recusive locking */
+	/* This is the shift value for the above recursive locking */
 	cpu_buffer->nest += NESTED_BITS;
 }
 
@@ -2718,7 +2718,7 @@ void ring_buffer_nest_end(struct ring_buffer *buffer)
 	/* disabled by ring_buffer_nest_start() */
 	cpu = raw_smp_processor_id();
 	cpu_buffer = buffer->buffers[cpu];
-	/* This is the shift value for the above recusive locking */
+	/* This is the shift value for the above recursive locking */
 	cpu_buffer->nest -= NESTED_BITS;
 	preempt_enable_notrace();
 }
@@ -2907,7 +2907,7 @@ rb_reserve_next_event(struct ring_buffer *buffer,
  * @buffer: the ring buffer to reserve from
  * @length: the length of the data to reserve (excluding event header)
  *
- * Returns a reseverd event on the ring buffer to copy directly to.
+ * Returns a reserved event on the ring buffer to copy directly to.
  * The user of this interface will need to get the body to write into
  * and can use the ring_buffer_event_data() interface.
  *
@@ -3009,7 +3009,7 @@ rb_decrement_entry(struct ring_buffer_per_cpu *cpu_buffer,
  * This function lets the user discard an event in the ring buffer
  * and then that event will not be read later.
  *
- * This function only works if it is called before the the item has been
+ * This function only works if it is called before the item has been
  * committed. It will try to free the event from the ring buffer
  * if another event has not been added behind it.
  *
@@ -4127,7 +4127,7 @@ EXPORT_SYMBOL_GPL(ring_buffer_consume);
  * through the buffer.  Memory is allocated, buffer recording
  * is disabled, and the iterator pointer is returned to the caller.
  *
- * Disabling buffer recordng prevents the reading from being
+ * Disabling buffer recording prevents the reading from being
  * corrupted. This is not a consuming read, so a producer is not
  * expected.
  *

kernel/trace/trace.c

@@ -4395,8 +4395,7 @@ static int trace_set_options(struct trace_array *tr, char *option)
 {
 	char *cmp;
 	int neg = 0;
-	int ret = -ENODEV;
-	int i;
+	int ret;
 	size_t orig_len = strlen(option);
 
 	cmp = strstrip(option);
@@ -4408,16 +4407,12 @@ static int trace_set_options(struct trace_array *tr, char *option)
 
 	mutex_lock(&trace_types_lock);
 
-	for (i = 0; trace_options[i]; i++) {
-		if (strcmp(cmp, trace_options[i]) == 0) {
-			ret = set_tracer_flag(tr, 1 << i, !neg);
-			break;
-		}
-	}
-
+	ret = match_string(trace_options, -1, cmp);
 	/* If no option could be set, test the specific tracer options */
-	if (!trace_options[i])
+	if (ret < 0)
 		ret = set_tracer_option(tr, cmp, neg);
+	else
+		ret = set_tracer_flag(tr, 1 << ret, !neg);
 
 	mutex_unlock(&trace_types_lock);
 
@@ -6074,6 +6069,7 @@ tracing_mark_write(struct file *filp, const char __user *ubuf,
 {
 	struct trace_array *tr = filp->private_data;
 	struct ring_buffer_event *event;
+	enum event_trigger_type tt = ETT_NONE;
 	struct ring_buffer *buffer;
 	struct print_entry *entry;
 	unsigned long irq_flags;
@@ -6122,6 +6118,12 @@ tracing_mark_write(struct file *filp, const char __user *ubuf,
 		written = cnt;
 	len = cnt;
 
+	if (tr->trace_marker_file && !list_empty(&tr->trace_marker_file->triggers)) {
+		/* do not add \n before testing triggers, but add \0 */
+		entry->buf[cnt] = '\0';
+		tt = event_triggers_call(tr->trace_marker_file, entry, event);
+	}
+
 	if (entry->buf[cnt - 1] != '\n') {
 		entry->buf[cnt] = '\n';
 		entry->buf[cnt + 1] = '\0';
@@ -6130,6 +6132,9 @@ tracing_mark_write(struct file *filp, const char __user *ubuf,
 
 	__buffer_unlock_commit(buffer, event);
 
+	if (tt)
+		event_triggers_post_call(tr->trace_marker_file, tt);
+
 	if (written > 0)
 		*fpos += written;
 
@@ -7896,6 +7901,7 @@ static __init void create_trace_instances(struct dentry *d_tracer)
 static void
 init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer)
 {
+	struct trace_event_file *file;
 	int cpu;
 
 	trace_create_file("available_tracers", 0444, d_tracer,
@@ -7928,6 +7934,12 @@ init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer)
 	trace_create_file("trace_marker", 0220, d_tracer,
 			  tr, &tracing_mark_fops);
 
+	file = __find_event_file(tr, "ftrace", "print");
+	if (file && file->dir)
+		trace_create_file("trigger", 0644, file->dir, file,
+				  &event_trigger_fops);
+	tr->trace_marker_file = file;
+
 	trace_create_file("trace_marker_raw", 0220, d_tracer,
 			  tr, &tracing_mark_raw_fops);
 
@@ -8111,6 +8123,8 @@ static __init int tracer_init_tracefs(void)
 	if (IS_ERR(d_tracer))
 		return 0;
 
+	event_trace_init();
+
 	init_tracer_tracefs(&global_trace, d_tracer);
 	ftrace_init_tracefs_toplevel(&global_trace, d_tracer);
 

kernel/trace/trace.h

@@ -259,6 +259,7 @@ struct trace_array {
 	struct trace_options	*topts;
 	struct list_head	systems;
 	struct list_head	events;
+	struct trace_event_file *trace_marker_file;
 	cpumask_var_t		tracing_cpumask; /* only trace on set CPUs */
 	int			ref;
 #ifdef CONFIG_FUNCTION_TRACER
@@ -1334,7 +1335,7 @@ event_trigger_unlock_commit(struct trace_event_file *file,
 		trace_buffer_unlock_commit(file->tr, buffer, event, irq_flags, pc);
 
 	if (tt)
-		event_triggers_post_call(file, tt, entry, event);
+		event_triggers_post_call(file, tt);
 }
 
 /**
@@ -1367,7 +1368,7 @@ event_trigger_unlock_commit_regs(struct trace_event_file *file,
 						irq_flags, pc, regs);
 
 	if (tt)
-		event_triggers_post_call(file, tt, entry, event);
+		event_triggers_post_call(file, tt);
 }
 
 #define FILTER_PRED_INVALID	((unsigned short)-1)
@@ -1451,9 +1452,13 @@ trace_find_event_field(struct trace_event_call *call, char *name);
 extern void trace_event_enable_cmd_record(bool enable);
 extern void trace_event_enable_tgid_record(bool enable);
 
+extern int event_trace_init(void);
 extern int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr);
 extern int event_trace_del_tracer(struct trace_array *tr);
 
+extern struct trace_event_file *__find_event_file(struct trace_array *tr,
+						  const char *system,
+						  const char *event);
 extern struct trace_event_file *find_event_file(struct trace_array *tr,
 						const char *system,
 						const char *event);

kernel/trace/trace_entries.h

@@ -230,7 +230,7 @@ FTRACE_ENTRY(bprint, bprint_entry,
 	FILTER_OTHER
 );
 
-FTRACE_ENTRY(print, print_entry,
+FTRACE_ENTRY_REG(print, print_entry,
 
 	TRACE_PRINT,
 
@@ -242,7 +242,9 @@ FTRACE_ENTRY(print, print_entry,
 	F_printk("%ps: %s",
 		 (void *)__entry->ip, __entry->buf),
 
-	FILTER_OTHER
+	FILTER_OTHER,
+
+	ftrace_event_register
 );
 
 FTRACE_ENTRY(raw_data, raw_data_entry,

kernel/trace/trace_events.c

@@ -2007,16 +2007,18 @@ event_create_dir(struct dentry *parent, struct trace_event_file *file)
 			return -1;
 		}
 	}
-	trace_create_file("filter", 0644, file->dir, file,
-			  &ftrace_event_filter_fops);
 
 	/*
 	 * Only event directories that can be enabled should have
-	 * triggers.
+	 * triggers or filters.
 	 */
-	if (!(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
+	if (!(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)) {
+		trace_create_file("filter", 0644, file->dir, file,
+				  &ftrace_event_filter_fops);
+
 		trace_create_file("trigger", 0644, file->dir, file,
 				  &event_trigger_fops);
+	}
 
 #ifdef CONFIG_HIST_TRIGGERS
 	trace_create_file("hist", 0444, file->dir, file,
@@ -2473,8 +2475,9 @@ __trace_add_event_dirs(struct trace_array *tr)
 	}
 }
 
+/* Returns any file that matches the system and event */
 struct trace_event_file *
-find_event_file(struct trace_array *tr, const char *system,  const char *event)
+__find_event_file(struct trace_array *tr, const char *system, const char *event)
 {
 	struct trace_event_file *file;
 	struct trace_event_call *call;
@@ -2485,10 +2488,7 @@ find_event_file(struct trace_array *tr, const char *system,  const char *event)
 		call = file->event_call;
 		name = trace_event_name(call);
 
-		if (!name || !call->class || !call->class->reg)
-			continue;
-
-		if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
+		if (!name || !call->class)
 			continue;
 
 		if (strcmp(event, name) == 0 &&
@@ -2498,6 +2498,20 @@ find_event_file(struct trace_array *tr, const char *system,  const char *event)
 	return NULL;
 }
 
+/* Returns valid trace event files that match system and event */
+struct trace_event_file *
+find_event_file(struct trace_array *tr, const char *system, const char *event)
+{
+	struct trace_event_file *file;
+
+	file = __find_event_file(tr, system, event);
+	if (!file || !file->event_call->class->reg ||
+	    file->event_call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
+		return NULL;
+
+	return file;
+}
+
 #ifdef CONFIG_DYNAMIC_FTRACE
 
 /* Avoid typos */
@@ -3132,7 +3146,7 @@ static __init int event_trace_enable_again(void)
 
 early_initcall(event_trace_enable_again);
 
-static __init int event_trace_init(void)
+__init int event_trace_init(void)
 {
 	struct trace_array *tr;
 	struct dentry *d_tracer;
@@ -3177,8 +3191,6 @@ void __init trace_event_init(void)
 	event_trace_enable();
 }
 
-fs_initcall(event_trace_init);
-
 #ifdef CONFIG_FTRACE_STARTUP_TEST
 
 static DEFINE_SPINLOCK(test_spinlock);