Merge tag 'libtraceevent-core-for-acme' of git://git.kernel.org/pub/scm/linux/kernel/git/namhyung/linux-perf into perf/core

libtraceevent/core improvements

* Remaining backport of trace-cmd's libparseevent

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

2 files changed, 251 insertions, 122 deletions

diff --git a/tools/lib/traceevent/event-parse.c b/tools/lib/traceevent/event-parse.c
index 83f0a8add17..5f34aa371b5 100644
--- a/tools/lib/traceevent/event-parse.c
+++ b/tools/lib/traceevent/event-parse.c
@@ -467,8 +467,10 @@ int pevent_register_function(struct pevent *pevent, char *func,
 		item->mod = NULL;
 	item->addr = addr;
 
-	pevent->funclist = item;
+	if (!item->func || (mod && !item->mod))
+		die("malloc func");
 
+	pevent->funclist = item;
 	pevent->func_count++;
 
 	return 0;
@@ -511,12 +513,12 @@ struct printk_list {
 
 static int printk_cmp(const void *a, const void *b)
 {
-	const struct func_map *fa = a;
-	const struct func_map *fb = b;
+	const struct printk_map *pa = a;
+	const struct printk_map *pb = b;
 
-	if (fa->addr < fb->addr)
+	if (pa->addr < pb->addr)
 		return -1;
-	if (fa->addr > fb->addr)
+	if (pa->addr > pb->addr)
 		return 1;
 
 	return 0;
@@ -583,10 +585,13 @@ int pevent_register_print_string(struct pevent *pevent, char *fmt,
 	item = malloc_or_die(sizeof(*item));
 
 	item->next = pevent->printklist;
-	pevent->printklist = item;
 	item->printk = strdup(fmt);
 	item->addr = addr;
 
+	if (!item->printk)
+		die("malloc fmt");
+
+	pevent->printklist = item;
 	pevent->printk_count++;
 
 	return 0;
@@ -628,12 +633,8 @@ static void add_event(struct pevent *pevent, struct event_format *event)
 {
 	int i;
 
-	if (!pevent->events)
-		pevent->events = malloc_or_die(sizeof(event));
-	else
-		pevent->events =
-			realloc(pevent->events, sizeof(event) *
-				(pevent->nr_events + 1));
+	pevent->events = realloc(pevent->events, sizeof(event) *
+				 (pevent->nr_events + 1));
 	if (!pevent->events)
 		die("Can not allocate events");
 
@@ -781,6 +782,25 @@ int pevent_peek_char(void)
 	return __peek_char();
 }
 
+static int extend_token(char **tok, char *buf, int size)
+{
+	char *newtok = realloc(*tok, size);
+
+	if (!newtok) {
+		free(*tok);
+		*tok = NULL;
+		return -1;
+	}
+
+	if (!*tok)
+		strcpy(newtok, buf);
+	else
+		strcat(newtok, buf);
+	*tok = newtok;
+
+	return 0;
+}
+
 static enum event_type force_token(const char *str, char **tok);
 
 static enum event_type __read_token(char **tok)
@@ -865,17 +885,10 @@ static enum event_type __read_token(char **tok)
 		do {
 			if (i == (BUFSIZ - 1)) {
 				buf[i] = 0;
-				if (*tok) {
-					*tok = realloc(*tok, tok_size + BUFSIZ);
-					if (!*tok)
-						return EVENT_NONE;
-					strcat(*tok, buf);
-				} else
-					*tok = strdup(buf);
+				tok_size += BUFSIZ;
 
-				if (!*tok)
+				if (extend_token(tok, buf, tok_size) < 0)
 					return EVENT_NONE;
-				tok_size += BUFSIZ;
 				i = 0;
 			}
 			last_ch = ch;
@@ -914,17 +927,10 @@ static enum event_type __read_token(char **tok)
 	while (get_type(__peek_char()) == type) {
 		if (i == (BUFSIZ - 1)) {
 			buf[i] = 0;
-			if (*tok) {
-				*tok = realloc(*tok, tok_size + BUFSIZ);
-				if (!*tok)
-					return EVENT_NONE;
-				strcat(*tok, buf);
-			} else
-				*tok = strdup(buf);
+			tok_size += BUFSIZ;
 
-			if (!*tok)
+			if (extend_token(tok, buf, tok_size) < 0)
 				return EVENT_NONE;
-			tok_size += BUFSIZ;
 			i = 0;
 		}
 		ch = __read_char();
@@ -933,14 +939,7 @@ static enum event_type __read_token(char **tok)
 
  out:
 	buf[i] = 0;
-	if (*tok) {
-		*tok = realloc(*tok, tok_size + i);
-		if (!*tok)
-			return EVENT_NONE;
-		strcat(*tok, buf);
-	} else
-		*tok = strdup(buf);
-	if (!*tok)
+	if (extend_token(tok, buf, tok_size + i + 1) < 0)
 		return EVENT_NONE;
 
 	if (type == EVENT_ITEM) {
@@ -1261,9 +1260,15 @@ static int event_read_fields(struct event_format *event, struct format_field **f
 					field->flags |= FIELD_IS_POINTER;
 
 				if (field->type) {
-					field->type = realloc(field->type,
-							      strlen(field->type) +
-							      strlen(last_token) + 2);
+					char *new_type;
+					new_type = realloc(field->type,
+							   strlen(field->type) +
+							   strlen(last_token) + 2);
+					if (!new_type) {
+						free(last_token);
+						goto fail;
+					}
+					field->type = new_type;
 					strcat(field->type, " ");
 					strcat(field->type, last_token);
 					free(last_token);
@@ -1288,6 +1293,7 @@ static int event_read_fields(struct event_format *event, struct format_field **f
 		if (strcmp(token, "[") == 0) {
 			enum event_type last_type = type;
 			char *brackets = token;
+			char *new_brackets;
 			int len;
 
 			field->flags |= FIELD_IS_ARRAY;
@@ -1307,9 +1313,14 @@ static int event_read_fields(struct event_format *event, struct format_field **f
 					len = 1;
 				last_type = type;
 
-				brackets = realloc(brackets,
-						   strlen(brackets) +
-						   strlen(token) + len);
+				new_brackets = realloc(brackets,
+						       strlen(brackets) +
+						       strlen(token) + len);
+				if (!new_brackets) {
+					free(brackets);
+					goto fail;
+				}
+				brackets = new_brackets;
 				if (len == 2)
 					strcat(brackets, " ");
 				strcat(brackets, token);
@@ -1325,7 +1336,12 @@ static int event_read_fields(struct event_format *event, struct format_field **f
 
 			free_token(token);
 
-			brackets = realloc(brackets, strlen(brackets) + 2);
+			new_brackets = realloc(brackets, strlen(brackets) + 2);
+			if (!new_brackets) {
+				free(brackets);
+				goto fail;
+			}
+			brackets = new_brackets;
 			strcat(brackets, "]");
 
 			/* add brackets to type */
@@ -1336,10 +1352,16 @@ static int event_read_fields(struct event_format *event, struct format_field **f
 			 * the format: type [] item;
 			 */
 			if (type == EVENT_ITEM) {
-				field->type = realloc(field->type,
-						      strlen(field->type) +
-						      strlen(field->name) +
-						      strlen(brackets) + 2);
+				char *new_type;
+				new_type = realloc(field->type,
+						   strlen(field->type) +
+						   strlen(field->name) +
+						   strlen(brackets) + 2);
+				if (!new_type) {
+					free(brackets);
+					goto fail;
+				}
+				field->type = new_type;
 				strcat(field->type, " ");
 				strcat(field->type, field->name);
 				free_token(field->name);
@@ -1347,9 +1369,15 @@ static int event_read_fields(struct event_format *event, struct format_field **f
 				field->name = token;
 				type = read_token(&token);
 			} else {
-				field->type = realloc(field->type,
-						      strlen(field->type) +
-						      strlen(brackets) + 1);
+				char *new_type;
+				new_type = realloc(field->type,
+						   strlen(field->type) +
+						   strlen(brackets) + 1);
+				if (!new_type) {
+					free(brackets);
+					goto fail;
+				}
+				field->type = new_type;
 				strcat(field->type, brackets);
 			}
 			free(brackets);
@@ -1732,10 +1760,16 @@ process_op(struct event_format *event, struct print_arg *arg, char **tok)
 		/* could just be a type pointer */
 		if ((strcmp(arg->op.op, "*") == 0) &&
 		    type == EVENT_DELIM && (strcmp(token, ")") == 0)) {
+			char *new_atom;
+
 			if (left->type != PRINT_ATOM)
 				die("bad pointer type");
-			left->atom.atom = realloc(left->atom.atom,
+			new_atom = realloc(left->atom.atom,
 					    strlen(left->atom.atom) + 3);
+			if (!new_atom)
+				goto out_free;
+
+			left->atom.atom = new_atom;
 			strcat(left->atom.atom, " *");
 			free(arg->op.op);
 			*arg = *left;
@@ -2152,6 +2186,8 @@ process_fields(struct event_format *event, struct print_flag_sym **list, char **
 		if (value == NULL)
 			goto out_free;
 		field->value = strdup(value);
+		if (field->value == NULL)
+			goto out_free;
 
 		free_arg(arg);
 		arg = alloc_arg();
@@ -2165,6 +2201,8 @@ process_fields(struct event_format *event, struct print_flag_sym **list, char **
 		if (value == NULL)
 			goto out_free;
 		field->str = strdup(value);
+		if (field->str == NULL)
+			goto out_free;
 		free_arg(arg);
 		arg = NULL;
 
@@ -2590,7 +2628,16 @@ process_arg_token(struct event_format *event, struct print_arg *arg,
 		}
 		/* atoms can be more than one token long */
 		while (type == EVENT_ITEM) {
-			atom = realloc(atom, strlen(atom) + strlen(token) + 2);
+			char *new_atom;
+			new_atom = realloc(atom,
+					   strlen(atom) + strlen(token) + 2);
+			if (!new_atom) {
+				free(atom);
+				*tok = NULL;
+				free_token(token);
+				return EVENT_ERROR;
+			}
+			atom = new_atom;
 			strcat(atom, " ");
 			strcat(atom, token);
 			free_token(token);
@@ -2884,7 +2931,7 @@ static int get_common_info(struct pevent *pevent,
 	event = pevent->events[0];
 	field = pevent_find_common_field(event, type);
 	if (!field)
-		die("field '%s' not found", type);
+		return -1;
 
 	*offset = field->offset;
 	*size = field->size;
@@ -2935,15 +2982,16 @@ static int parse_common_flags(struct pevent *pevent, void *data)
 
 static int parse_common_lock_depth(struct pevent *pevent, void *data)
 {
-	int ret;
-
-	ret = __parse_common(pevent, data,
-			     &pevent->ld_size, &pevent->ld_offset,
-			     "common_lock_depth");
-	if (ret < 0)
-		return -1;
+	return __parse_common(pevent, data,
+			      &pevent->ld_size, &pevent->ld_offset,
+			      "common_lock_depth");
+}
 
-	return ret;
+static int parse_common_migrate_disable(struct pevent *pevent, void *data)
+{
+	return __parse_common(pevent, data,
+			      &pevent->ld_size, &pevent->ld_offset,
+			      "common_migrate_disable");
 }
 
 static int events_id_cmp(const void *a, const void *b);
@@ -3370,7 +3418,7 @@ static void print_str_arg(struct trace_seq *s, void *data, int size,
 		break;
 	}
 	case PRINT_BSTRING:
-		trace_seq_printf(s, format, arg->string.string);
+		print_str_to_seq(s, format, len_arg, arg->string.string);
 		break;
 	case PRINT_OP:
 		/*
@@ -3434,6 +3482,10 @@ process_defined_func(struct trace_seq *s, void *data, int size,
 			string = malloc_or_die(sizeof(*string));
 			string->next = strings;
 			string->str = strdup(str.buffer);
+			if (!string->str)
+				die("malloc str");
+
+			args[i] = (unsigned long long)string->str;
 			strings = string;
 			trace_seq_destroy(&str);
 			break;
@@ -3471,6 +3523,7 @@ static struct print_arg *make_bprint_args(char *fmt, void *data, int size, struc
 	unsigned long long ip, val;
 	char *ptr;
 	void *bptr;
+	int vsize;
 
 	field = pevent->bprint_buf_field;
 	ip_field = pevent->bprint_ip_field;
@@ -3519,6 +3572,8 @@ static struct print_arg *make_bprint_args(char *fmt, void *data, int size, struc
 				goto process_again;
 			case '0' ... '9':
 				goto process_again;
+			case '.':
+				goto process_again;
 			case 'p':
 				ls = 1;
 				/* fall through */
@@ -3526,23 +3581,30 @@ static struct print_arg *make_bprint_args(char *fmt, void *data, int size, struc
 			case 'u':
 			case 'x':
 			case 'i':
-				/* the pointers are always 4 bytes aligned */
-				bptr = (void *)(((unsigned long)bptr + 3) &
-						~3);
 				switch (ls) {
 				case 0:
-					ls = 4;
+					vsize = 4;
 					break;
 				case 1:
-					ls = pevent->long_size;
+					vsize = pevent->long_size;
 					break;
 				case 2:
-					ls = 8;
+					vsize = 8;
+					break;
 				default:
+					vsize = ls; /* ? */
 					break;
 				}
-				val = pevent_read_number(pevent, bptr, ls);
-				bptr += ls;
+			/* fall through */
+			case '*':
+				if (*ptr == '*')
+					vsize = 4;
+
+				/* the pointers are always 4 bytes aligned */
+				bptr = (void *)(((unsigned long)bptr + 3) &
+						~3);
+				val = pevent_read_number(pevent, bptr, vsize);
+				bptr += vsize;
 				arg = alloc_arg();
 				arg->next = NULL;
 				arg->type = PRINT_ATOM;
@@ -3550,12 +3612,21 @@ static struct print_arg *make_bprint_args(char *fmt, void *data, int size, struc
 				sprintf(arg->atom.atom, "%lld", val);
 				*next = arg;
 				next = &arg->next;
+				/*
+				 * The '*' case means that an arg is used as the length.
+				 * We need to continue to figure out for what.
+				 */
+				if (*ptr == '*')
+					goto process_again;
+
 				break;
 			case 's':
 				arg = alloc_arg();
 				arg->next = NULL;
 				arg->type = PRINT_BSTRING;
 				arg->string.string = strdup(bptr);
+				if (!arg->string.string)
+					break;
 				bptr += strlen(bptr) + 1;
 				*next = arg;
 				next = &arg->next;
@@ -3841,6 +3912,7 @@ static void pretty_print(struct trace_seq *s, void *data, int size, struct event
 				} else if (*(ptr+1) == 'M' || *(ptr+1) == 'm') {
 					print_mac_arg(s, *(ptr+1), data, size, event, arg);
 					ptr++;
+					arg = arg->next;
 					break;
 				}
 
@@ -3877,14 +3949,15 @@ static void pretty_print(struct trace_seq *s, void *data, int size, struct event
 						break;
 					}
 				}
-				if (pevent->long_size == 8 && ls) {
+				if (pevent->long_size == 8 && ls &&
+				    sizeof(long) != 8) {
 					char *p;
 
 					ls = 2;
 					/* make %l into %ll */
 					p = strchr(format, 'l');
 					if (p)
-						memmove(p, p+1, strlen(p)+1);
+						memmove(p+1, p, strlen(p)+1);
 					else if (strcmp(format, "%p") == 0)
 						strcpy(format, "0x%llx");
 				}
@@ -3961,8 +4034,7 @@ static void pretty_print(struct trace_seq *s, void *data, int size, struct event
  * pevent_data_lat_fmt - parse the data for the latency format
  * @pevent: a handle to the pevent
  * @s: the trace_seq to write to
- * @data: the raw data to read from
- * @size: currently unused.
+ * @record: the record to read from
  *
  * This parses out the Latency format (interrupts disabled,
  * need rescheduling, in hard/soft interrupt, preempt count
@@ -3972,10 +4044,13 @@ void pevent_data_lat_fmt(struct pevent *pevent,
 			 struct trace_seq *s, struct pevent_record *record)
 {
 	static int check_lock_depth = 1;
+	static int check_migrate_disable = 1;
 	static int lock_depth_exists;
+	static int migrate_disable_exists;
 	unsigned int lat_flags;
 	unsigned int pc;
 	int lock_depth;
+	int migrate_disable;
 	int hardirq;
 	int softirq;
 	void *data = record->data;
@@ -3983,18 +4058,26 @@ void pevent_data_lat_fmt(struct pevent *pevent,
 	lat_flags = parse_common_flags(pevent, data);
 	pc = parse_common_pc(pevent, data);
 	/* lock_depth may not always exist */
-	if (check_lock_depth) {
-		struct format_field *field;
-		struct event_format *event;
-
-		check_lock_depth = 0;
-		event = pevent->events[0];
-		field = pevent_find_common_field(event, "common_lock_depth");
-		if (field)
-			lock_depth_exists = 1;
-	}
 	if (lock_depth_exists)
 		lock_depth = parse_common_lock_depth(pevent, data);
+	else if (check_lock_depth) {
+		lock_depth = parse_common_lock_depth(pevent, data);
+		if (lock_depth < 0)
+			check_lock_depth = 0;
+		else
+			lock_depth_exists = 1;
+	}
+
+	/* migrate_disable may not always exist */
+	if (migrate_disable_exists)
+		migrate_disable = parse_common_migrate_disable(pevent, data);
+	else if (check_migrate_disable) {
+		migrate_disable = parse_common_migrate_disable(pevent, data);
+		if (migrate_disable < 0)
+			check_migrate_disable = 0;
+		else
+			migrate_disable_exists = 1;
+	}
 
 	hardirq = lat_flags & TRACE_FLAG_HARDIRQ;
 	softirq = lat_flags & TRACE_FLAG_SOFTIRQ;
@@ -4013,6 +4096,13 @@ void pevent_data_lat_fmt(struct pevent *pevent,
 	else
 		trace_seq_putc(s, '.');
 
+	if (migrate_disable_exists) {
+		if (migrate_disable < 0)
+			trace_seq_putc(s, '.');
+		else
+			trace_seq_printf(s, "%d", migrate_disable);
+	}
+
 	if (lock_depth_exists) {
 		if (lock_depth < 0)
 			trace_seq_putc(s, '.');
@@ -4079,10 +4169,7 @@ const char *pevent_data_comm_from_pid(struct pevent *pevent, int pid)
  * pevent_data_comm_from_pid - parse the data into the print format
  * @s: the trace_seq to write to
  * @event: the handle to the event
- * @cpu: the cpu the event was recorded on
- * @data: the raw data
- * @size: the size of the raw data
- * @nsecs: the timestamp of the event
+ * @record: the record to read from
  *
  * This parses the raw @data using the given @event information and
  * writes the print format into the trace_seq.
@@ -4631,6 +4718,8 @@ int pevent_parse_event(struct pevent *pevent,
 		die("failed to read event id");
 
 	event->system = strdup(sys);
+	if (!event->system)
+		die("failed to allocate system");
 
 	/* Add pevent to event so that it can be referenced */
 	event->pevent = pevent;
@@ -4672,6 +4761,11 @@ int pevent_parse_event(struct pevent *pevent,
 			list = &arg->next;
 			arg->type = PRINT_FIELD;
 			arg->field.name = strdup(field->name);
+			if (!arg->field.name) {
+				do_warning("failed to allocate field name");
+				event->flags |= EVENT_FL_FAILED;
+				return -1;
+			}
 			arg->field.field = field;
 		}
 		return 0;
@@ -4843,7 +4937,7 @@ int pevent_get_any_field_val(struct trace_seq *s, struct event_format *event,
  * @record: The record with the field name.
  * @err: print default error if failed.
  *
- * Returns: 0 on success, -1 field not fould, or 1 if buffer is full.
+ * Returns: 0 on success, -1 field not found, or 1 if buffer is full.
  */
 int pevent_print_num_field(struct trace_seq *s, const char *fmt,
 			   struct event_format *event, const char *name,
@@ -4885,11 +4979,12 @@ static void free_func_handle(struct pevent_function_handler *func)
  * pevent_register_print_function - register a helper function
  * @pevent: the handle to the pevent
  * @func: the function to process the helper function
+ * @ret_type: the return type of the helper function
  * @name: the name of the helper function
  * @parameters: A list of enum pevent_func_arg_type
  *
  * Some events may have helper functions in the print format arguments.
- * This allows a plugin to dynmically create a way to process one
+ * This allows a plugin to dynamically create a way to process one
  * of these functions.
  *
  * The @parameters is a variable list of pevent_func_arg_type enums that
@@ -4960,12 +5055,13 @@ int pevent_register_print_function(struct pevent *pevent,
 }
 
 /**
- * pevent_register_event_handle - register a way to parse an event
+ * pevent_register_event_handler - register a way to parse an event
  * @pevent: the handle to the pevent
  * @id: the id of the event to register
  * @sys_name: the system name the event belongs to
  * @event_name: the name of the event
  * @func: the function to call to parse the event information
+ * @context: the data to be passed to @func
  *
  * This function allows a developer to override the parsing of
  * a given event. If for some reason the default print format
@@ -5015,6 +5111,11 @@ int pevent_register_event_handler(struct pevent *pevent,
 	if (sys_name)
 		handle->sys_name = strdup(sys_name);
 
+	if ((event_name && !handle->event_name) ||
+	    (sys_name && !handle->sys_name)) {
+		die("Failed to allocate event/sys name");
+	}
+
 	handle->func = func;
 	handle->next = pevent->handlers;
 	pevent->handlers = handle;
diff --git a/tools/lib/traceevent/parse-filter.c b/tools/lib/traceevent/parse-filter.c
index dfcfe2c131d..ad17855528f 100644
--- a/tools/lib/traceevent/parse-filter.c
+++ b/tools/lib/traceevent/parse-filter.c
@@ -96,7 +96,7 @@ static enum event_type read_token(char **tok)
 	    (strcmp(token, "=") == 0 || strcmp(token, "!") == 0) &&
 	    pevent_peek_char() == '~') {
 		/* append it */
-		*tok = malloc(3);
+		*tok = malloc_or_die(3);
 		sprintf(*tok, "%c%c", *token, '~');
 		free_token(token);
 		/* Now remove the '~' from the buffer */
@@ -148,17 +148,11 @@ add_filter_type(struct event_filter *filter, int id)
 	if (filter_type)
 		return filter_type;
 
-	if (!filter->filters)
-		filter->event_filters =
-			malloc_or_die(sizeof(*filter->event_filters));
-	else {
-		filter->event_filters =
-			realloc(filter->event_filters,
-				sizeof(*filter->event_filters) *
-				(filter->filters + 1));
-		if (!filter->event_filters)
-			die("Could not allocate filter");
-	}
+	filter->event_filters =	realloc(filter->event_filters,
+					sizeof(*filter->event_filters) *
+					(filter->filters + 1));
+	if (!filter->event_filters)
+		die("Could not allocate filter");
 
 	for (i = 0; i < filter->filters; i++) {
 		if (filter->event_filters[i].event_id > id)
@@ -1480,7 +1474,7 @@ void pevent_filter_clear_trivial(struct event_filter *filter,
 {
 	struct filter_type *filter_type;
 	int count = 0;
-	int *ids;
+	int *ids = NULL;
 	int i;
 
 	if (!filter->filters)
@@ -1504,10 +1498,8 @@ void pevent_filter_clear_trivial(struct event_filter *filter,
 		default:
 			break;
 		}
-		if (count)
-			ids = realloc(ids, sizeof(*ids) * (count + 1));
-		else
-			ids = malloc(sizeof(*ids));
+
+		ids = realloc(ids, sizeof(*ids) * (count + 1));
 		if (!ids)
 			die("Can't allocate ids");
 		ids[count++] = filter_type->event_id;
@@ -1710,18 +1702,43 @@ static int test_num(struct event_format *event,
 
 static const char *get_field_str(struct filter_arg *arg, struct pevent_record *record)
 {
-	const char *val = record->data + arg->str.field->offset;
+	struct event_format *event;
+	struct pevent *pevent;
+	unsigned long long addr;
+	const char *val = NULL;
+	char hex[64];
 
-	/*
-	 * We need to copy the data since we can't be sure the field
-	 * is null terminated.
-	 */
-	if (*(val + arg->str.field->size - 1)) {
-		/* copy it */
-		memcpy(arg->str.buffer, val, arg->str.field->size);
-		/* the buffer is already NULL terminated */
-		val = arg->str.buffer;
+	/* If the field is not a string convert it */
+	if (arg->str.field->flags & FIELD_IS_STRING) {
+		val = record->data + arg->str.field->offset;
+
+		/*
+		 * We need to copy the data since we can't be sure the field
+		 * is null terminated.
+		 */
+		if (*(val + arg->str.field->size - 1)) {
+			/* copy it */
+			memcpy(arg->str.buffer, val, arg->str.field->size);
+			/* the buffer is already NULL terminated */
+			val = arg->str.buffer;
+		}
+
+	} else {
+		event = arg->str.field->event;
+		pevent = event->pevent;
+		addr = get_value(event, arg->str.field, record);
+
+		if (arg->str.field->flags & (FIELD_IS_POINTER | FIELD_IS_LONG))
+			/* convert to a kernel symbol */
+			val = pevent_find_function(pevent, addr);
+
+		if (val == NULL) {
+			/* just use the hex of the string name */
+			snprintf(hex, 64, "0x%llx", addr);
+			val = hex;
+		}
 	}
+
 	return val;
 }
 
@@ -2001,11 +2018,13 @@ static char *exp_to_str(struct event_filter *filter, struct filter_arg *arg)
 	char *lstr;
 	char *rstr;
 	char *op;
-	char *str;
+	char *str = NULL;
 	int len;
 
 	lstr = arg_to_str(filter, arg->exp.left);
 	rstr = arg_to_str(filter, arg->exp.right);
+	if (!lstr || !rstr)
+		goto out;
 
 	switch (arg->exp.type) {
 	case FILTER_EXP_ADD:
@@ -2045,6 +2064,7 @@ static char *exp_to_str(struct event_filter *filter, struct filter_arg *arg)
 	len = strlen(op) + strlen(lstr) + strlen(rstr) + 4;
 	str = malloc_or_die(len);
 	snprintf(str, len, "%s %s %s", lstr, op, rstr);
+out:
 	free(lstr);
 	free(rstr);
 
@@ -2061,6 +2081,8 @@ static char *num_to_str(struct event_filter *filter, struct filter_arg *arg)
 
 	lstr = arg_to_str(filter, arg->num.left);
 	rstr = arg_to_str(filter, arg->num.right);
+	if (!lstr || !rstr)
+		goto out;
 
 	switch (arg->num.type) {
 	case FILTER_CMP_EQ:
@@ -2097,6 +2119,7 @@ static char *num_to_str(struct event_filter *filter, struct filter_arg *arg)
 		break;
 	}
 
+out:
 	free(lstr);
 	free(rstr);
 	return str;
@@ -2247,7 +2270,12 @@ int pevent_filter_compare(struct event_filter *filter1, struct event_filter *fil
 		/* The best way to compare complex filters is with strings */
 		str1 = arg_to_str(filter1, filter_type1->filter);
 		str2 = arg_to_str(filter2, filter_type2->filter);
-		result = strcmp(str1, str2) != 0;
+		if (str1 && str2)
+			result = strcmp(str1, str2) != 0;
+		else
+			/* bail out if allocation fails */
+			result = 1;
+
 		free(str1);
 		free(str2);
 		if (result)