Commit 6a475cb1 authored by Tom Zanussi's avatar Tom Zanussi Committed by Steven Rostedt
Browse files

tracing: Remove restriction on string position in hist trigger keys 

If we assume the maximum size for a string field, we don't have to
worry about its position.  Since we only allow two keys in a compound
key and having more than one string key in a given compound key
doesn't make much sense anyway, trading a bit of extra space instead
of introducing an arbitrary restriction makes more sense.

We also need to use the event field size for static strings when
copying the contents, otherwise we get random garbage in the key.

Also, cast string return values to avoid warnings on 32-bit compiles.

Finally, rearrange the code without changing any functionality by
moving the compound key updating code into a separate function.

Link: http://lkml.kernel.org/r/8976e1ab04b66bc2700ad1ed0768a2de85ac1983.1457029949.git.tom.zanussi@linux.intel.com



Signed-off-by: default avatarTom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: default avatarMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: default avatarNamhyung Kim <namhyung@kernel.org>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent 79e577cb

kernel/trace/trace_events_hist.c

+35 −28
Original line number Original line Diff line number Diff line
@@ -530,8 +530,8 @@ static int create_key_field(struct hist_trigger_data *hist_data, 
			goto out;

			goto out;

		}

		}





		if (is_string_field(field)) /* should be last key field */

		if (is_string_field(field))

			key_size = HIST_KEY_SIZE_MAX - key_offset;

			key_size = MAX_FILTER_STR_VAL;

		else

		else

			key_size = field->size;

			key_size = field->size;

	}

	}
@@ -830,9 +830,34 @@ static void hist_trigger_elt_update(struct hist_trigger_data *hist_data, 
	}

	}

}

}





static inline void add_to_key(char *compound_key, void *key,

			      struct hist_field *key_field, void *rec)

{

	size_t size = key_field->size;



	if (key_field->flags & HIST_FIELD_FL_STRING) {

		struct ftrace_event_field *field;



		field = key_field->field;

		if (field->filter_type == FILTER_DYN_STRING)

			size = *(u32 *)(rec + field->offset) >> 16;

		else if (field->filter_type == FILTER_PTR_STRING)

			size = strlen(key);

		else if (field->filter_type == FILTER_STATIC_STRING)

			size = field->size;



		/* ensure NULL-termination */

		if (size > key_field->size - 1)

			size = key_field->size - 1;

	}



	memcpy(compound_key + key_field->offset, key, size);

}



static void event_hist_trigger(struct event_trigger_data *data, void *rec)

static void event_hist_trigger(struct event_trigger_data *data, void *rec)

{

{

	struct hist_trigger_data *hist_data = data->private_data;

	struct hist_trigger_data *hist_data = data->private_data;

	bool use_compound_key = (hist_data->n_keys > 1);

	unsigned long entries[HIST_STACKTRACE_DEPTH];

	unsigned long entries[HIST_STACKTRACE_DEPTH];

	char compound_key[HIST_KEY_SIZE_MAX];

	char compound_key[HIST_KEY_SIZE_MAX];

	struct stack_trace stacktrace;

	struct stack_trace stacktrace;
@@ -842,7 +867,6 @@ static void event_hist_trigger(struct event_trigger_data *data, void *rec) 
	void *key = NULL;

	void *key = NULL;

	unsigned int i;

	unsigned int i;





	if (hist_data->n_keys > 1)

	memset(compound_key, 0, hist_data->key_size);

	memset(compound_key, 0, hist_data->key_size);





	for_each_hist_key_field(i, hist_data) {

	for_each_hist_key_field(i, hist_data) {
@@ -860,35 +884,18 @@ static void event_hist_trigger(struct event_trigger_data *data, void *rec) 
			key = entries;

			key = entries;

		} else {

		} else {

			field_contents = key_field->fn(key_field, rec);

			field_contents = key_field->fn(key_field, rec);

			if (key_field->flags & HIST_FIELD_FL_STRING)

			if (key_field->flags & HIST_FIELD_FL_STRING) {

				key = (void *)(unsigned long)field_contents;

				key = (void *)(unsigned long)field_contents;

			else

				use_compound_key = true;

			} else

				key = (void *)&field_contents;

				key = (void *)&field_contents;



			if (hist_data->n_keys > 1) {

				/* ensure NULL-termination */

				size_t size = key_field->size - 1;



				if (key_field->flags & HIST_FIELD_FL_STRING) {

					struct ftrace_event_field *field;



					field = key_field->field;

					if (field->filter_type == FILTER_DYN_STRING)

						size = *(u32 *)(rec + field->offset) >> 16;

					else if (field->filter_type == FILTER_PTR_STRING)

						size = strlen(key);



					if (size > key_field->size - 1)

						size = key_field->size - 1;

		}

		}





				memcpy(compound_key + key_field->offset, key,

		if (use_compound_key)

				       size);

			add_to_key(compound_key, key, key_field, rec);

			}

		}

	}

	}





	if (hist_data->n_keys > 1)

	if (use_compound_key)

		key = compound_key;

		key = compound_key;





	elt = tracing_map_insert(hist_data->map, key);

	elt = tracing_map_insert(hist_data->map, key);

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