Commit 05daae0f authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'trace-v5.14-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace 

Pull tracing fixes from Steven Rostedt:

 - Fix deadloop in ring buffer because of using stale "read" variable

 - Fix synthetic event use of field_pos as boolean and not an index

 - Fixed histogram special var "cpu" overriding event fields called
   "cpu"

 - Cleaned up error prone logic in alloc_synth_event()

 - Removed call to synchronize_rcu_tasks_rude() when not needed

 - Removed redundant initialization of a local variable "ret"

 - Fixed kernel crash when updating tracepoint callbacks of different
   priorities.

* tag 'trace-v5.14-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracepoints: Update static_call before tp_funcs when adding a tracepoint
  ftrace: Remove redundant initialization of variable ret
  ftrace: Avoid synchronize_rcu_tasks_rude() call when not necessary
  tracing: Clean up alloc_synth_event()
  tracing/histogram: Rename "cpu" to "common_cpu"
  tracing: Synthetic event field_pos is an index not a boolean
  tracing: Fix bug in rb_per_cpu_empty() that might cause deadloop.
parents 1af09ed5 352384d5

Documentation/trace/histogram.rst

+1 −1
Original line number Diff line number Diff line
@@ -191,7 +191,7 @@ Documentation written by Tom Zanussi 
                                with the event, in nanoseconds.  May be

			        modified by .usecs to have timestamps

			        interpreted as microseconds.

    cpu                    int  the cpu on which the event occurred.

    common_cpu             int  the cpu on which the event occurred.

    ====================== ==== =======================================



Extended error information

kernel/trace/ftrace.c

+3 −2
Original line number Diff line number Diff line
@@ -5985,6 +5985,7 @@ ftrace_graph_release(struct inode *inode, struct file *file) 
		 * infrastructure to do the synchronization, thus we must do it

		 * ourselves.

		 */

		if (old_hash != EMPTY_HASH)

			synchronize_rcu_tasks_rude();



		free_ftrace_hash(old_hash);
@@ -7544,7 +7545,7 @@ int ftrace_is_dead(void) 
 */

int register_ftrace_function(struct ftrace_ops *ops)

{

	int ret = -1;

	int ret;



	ftrace_ops_init(ops);

kernel/trace/ring_buffer.c

+24 −4
Original line number Diff line number Diff line
@@ -3880,10 +3880,30 @@ static bool rb_per_cpu_empty(struct ring_buffer_per_cpu *cpu_buffer) 
	if (unlikely(!head))

		return true;



	return reader->read == rb_page_commit(reader) &&

		(commit == reader ||

		 (commit == head &&

		  head->read == rb_page_commit(commit)));

	/* Reader should exhaust content in reader page */

	if (reader->read != rb_page_commit(reader))

		return false;



	/*

	 * If writers are committing on the reader page, knowing all

	 * committed content has been read, the ring buffer is empty.

	 */

	if (commit == reader)

		return true;



	/*

	 * If writers are committing on a page other than reader page

	 * and head page, there should always be content to read.

	 */

	if (commit != head)

		return false;



	/*

	 * Writers are committing on the head page, we just need

	 * to care about there're committed data, and the reader will

	 * swap reader page with head page when it is to read data.

	 */

	return rb_page_commit(commit) == 0;

}



/**

kernel/trace/trace.c

+4 −0
Original line number Diff line number Diff line
@@ -5609,6 +5609,10 @@ static const char readme_msg[] = 
	"\t            [:name=histname1]\n"

	"\t            [:<handler>.<action>]\n"

	"\t            [if <filter>]\n\n"

	"\t    Note, special fields can be used as well:\n"

	"\t            common_timestamp - to record current timestamp\n"

	"\t            common_cpu - to record the CPU the event happened on\n"

	"\n"

	"\t    When a matching event is hit, an entry is added to a hash\n"

	"\t    table using the key(s) and value(s) named, and the value of a\n"

	"\t    sum called 'hitcount' is incremented.  Keys and values\n"

kernel/trace/trace_events_hist.c

+16 −6
Original line number Diff line number Diff line
@@ -1111,7 +1111,7 @@ static const char *hist_field_name(struct hist_field *field, 
		 field->flags & HIST_FIELD_FL_ALIAS)

		field_name = hist_field_name(field->operands[0], ++level);

	else if (field->flags & HIST_FIELD_FL_CPU)

		field_name = "cpu";

		field_name = "common_cpu";

	else if (field->flags & HIST_FIELD_FL_EXPR ||

		 field->flags & HIST_FIELD_FL_VAR_REF) {

		if (field->system) {
@@ -1991,16 +1991,26 @@ parse_field(struct hist_trigger_data *hist_data, struct trace_event_file *file, 
		hist_data->enable_timestamps = true;

		if (*flags & HIST_FIELD_FL_TIMESTAMP_USECS)

			hist_data->attrs->ts_in_usecs = true;

	} else if (strcmp(field_name, "cpu") == 0)

	} else if (strcmp(field_name, "common_cpu") == 0)

		*flags |= HIST_FIELD_FL_CPU;

	else {

		field = trace_find_event_field(file->event_call, field_name);

		if (!field || !field->size) {

			hist_err(tr, HIST_ERR_FIELD_NOT_FOUND, errpos(field_name));

			/*

			 * For backward compatibility, if field_name

			 * was "cpu", then we treat this the same as

			 * common_cpu.

			 */

			if (strcmp(field_name, "cpu") == 0) {

				*flags |= HIST_FIELD_FL_CPU;

			} else {

				hist_err(tr, HIST_ERR_FIELD_NOT_FOUND,

					 errpos(field_name));

				field = ERR_PTR(-EINVAL);

				goto out;

			}

		}

	}

 out:

	kfree(str);
@@ -5085,7 +5095,7 @@ static void hist_field_print(struct seq_file *m, struct hist_field *hist_field) 
		seq_printf(m, "%s=", hist_field->var.name);



	if (hist_field->flags & HIST_FIELD_FL_CPU)

		seq_puts(m, "cpu");

		seq_puts(m, "common_cpu");

	else if (field_name) {

		if (hist_field->flags & HIST_FIELD_FL_VAR_REF ||

		    hist_field->flags & HIST_FIELD_FL_ALIAS)