[PATCH v3 1/9] perf tools: add parse events append error

Ian Rogers
2019-10-24T19:02:16Z

Parse event error handling may overwrite one error string with another
creating memory leaks and masking errors. Introduce a helper routine
that appends error messages and avoids the memory leak.

A reproduction of this problem can be seen with:
perf stat -e c/c/
After this change this produces:
event syntax error: 'c/c/'
\___ unknown term (previous error: unknown term (previous error: unknown term (previous error: unknown term (previous error: unknown term (previous error: unknown term (previous error: unknown term (previous error: unknown term (previous error: unknown term (previous error: unknown term (previous error: unknown term (previous error: unknown term (previous error: unknown term (previous error: unknown term (previous error: unknown term (previous error: unknown term (previous error: unknown term (previous error: unknown term (previous error: unknown term (previous error: unknown term (previous error: unknown term (previous error: Cannot find PMU `c'. Missing kernel support?)(help: valid terms: event,filter_rem,filter_opc0,edge,filter_isoc,filter_tid,filter_loc,filter_nc,inv,umask,filter_opc1,tid_en,thresh,filter_all_op,filter_not_nm,filter_state,filter_nm,config,config1,config2,name,period,percore))(help: valid terms: event,filter_rem,filter_opc0,edge,filter_isoc,filter_tid,filter_loc,filter_nc,inv,umask,filter_opc1,tid_en,thresh,filter_all_op,filter_not_nm,filter_state,filter_nm,config,config1,config2,name,period,percore))(help: valid terms: event,filter_rem,filter_opc0,edge,filter_isoc,filter_tid,filter_loc,filter_nc,inv,umask,filter_opc1,tid_en,thresh,filter_all_op,filter_not_nm,filter_state,filter_nm,config,config1,config2,name,period,percore))(help: valid terms: event,filter_rem,filter_opc0,edge,filter_isoc,filter_tid,filter_loc,filter_nc,inv,umask,filter_opc1,tid_en,thresh,filter_all_op,filter_not_nm,filter_state,filter_nm,config,config1,config2,name,period,percore))(help: valid terms: event,filter_rem,filter_opc0,edge,filter_isoc,filter_tid,filter_loc,filter_nc,inv,umask,filter_opc1,tid_en,thresh,filter_all_op,filter_not_nm,filter_state,filter_nm,config,config1,config2,name,period,percore))(help: valid terms: event,filter_rem,filter_opc0,edge,filter_isoc,filter_tid,filter_loc,filter_nc,inv,umask,filter_opc1,tid_en,thresh,filter_all_op,filter_not_nm,filter_state,filter_nm,config,config1,config2,name,period,percore))(help: valid terms: event,pc,in_tx,edge,any,offcore_rsp,in_tx_cp,ldlat,inv,umask,frontend,cmask,config,config1,config2,name,period,percore))(help: valid terms: event,filter_rem,filter_opc0,edge,filter_isoc,filter_tid,filter_loc,filter_nc,inv,umask,filter_opc1,tid_en,thresh,filter_all_op,filter_not_nm,filter_state,filter_nm,config,config1,config2,name,period,percore))(help: valid terms: event,filter_rem,filter_opc0,edge,filter_isoc,filter_tid,filter_loc,filter_nc,inv,umask,filter_opc1,tid_en,thresh,filter_all_op,filter_not_nm,filter_state,filter_nm,config,config1,config2,name,period,percore))(help: valid terms: event,config,config1,config2,name,period,percore))(help: valid terms: event,filter_rem,filter_opc0,edge,filter_isoc,filter_tid,filter_loc,filter_nc,inv,umask,filter_opc1,tid_en,thresh,filter_all_op,filter_not_nm,filter_state,filter_nm,config,config1,config2,name,period,percore))(help: valid terms: event,filter_rem,filter_opc0,edge,filter_isoc,filter_tid,filter_loc,filter_nc,inv,umask,filter_opc1,tid_en,thresh,filter_all_op,filter_not_nm,filter_state,filter_nm,config,config1,config2,name,period,percore))(help: valid terms: event,filter_rem,filter_opc0,edge,filter_isoc,filter_tid,filter_loc,filter_nc,inv,umask,filter_opc1,tid_en,thresh,filter_all_op,filter_not_nm,filter_state,filter_nm,config,config1,config2,name,period,percore))(help: valid terms: event,filter_rem,filter_opc0,edge,filter_isoc,filter_tid,filter_loc,filter_nc,inv,umask,filter_opc1,tid_en,thresh,filter_all_op,filter_not_nm,filter_state,filter_nm,config,config1,config2,name,period,percore))(help: valid terms: event,config,config1,config2,name,period,percore))(help: valid terms: event,filter_rem,filter_opc0,edge,filter_isoc,filter_tid,filter_loc,filter_nc,inv,umask,filter_opc1,tid_en,thresh,filter_all_op,filter_not_nm,filter_state,filter_nm,config,config1,config2,name,period,percore))(help: valid terms: event,filter_rem,filter_opc0,edge,filter_isoc,filter_tid,filter_loc,filter_nc,inv,umask,filter_opc1,tid_en,thresh,filter_all_op,filter_not_nm,filter_state,filter_nm,config,config1,config2,name,period,percore))(help: valid terms: event,filter_rem,filter_opc0,edge,filter_isoc,filter_tid,filter_loc,filter_nc,inv,umask,filter_opc1,tid_en,thresh,filter_all_op,filter_not_nm,filter_state,filter_nm,config,config1,config2,name,period,percore))(help: valid terms: event,filter_rem,filter_opc0,edge,filter_isoc,filter_tid,filter_loc,filter_nc,inv,umask,filter_opc1,tid_en,thresh,filter_all_op,filter_not_nm,filter_state,filter_nm,config,config1,config2,name,period,percore))(help: valid terms: event,filter_rem,filter_opc0,edge,filter_isoc,filter_tid,filter_loc,filter_nc,inv,umask,filter_opc1,tid_en,thresh,filter_all_op,filter_not_nm,filter_state,filter_nm,config,config1,config2,name,period,percore))

valid terms: event,filter_rem,filter_opc0,edge,filter_isoc,filter_tid,filter_loc,filter_nc,inv,umask,filter_opc1,tid_en,thresh,filter_all_op,filter_not_nm,filter_state,filter_nm,config,config1,config2,name,period,percore
Run 'perf list' for a list of valid events

Usage: perf stat [<options>] [<command>]

-e, --event <event> event selector. use 'perf list' to list available events

Signed-off-by: Ian Rogers <irogers@google.com>
---
tools/perf/util/parse-events.c | 100 +++++++++++++++++++++++----------
tools/perf/util/parse-events.h | 2 +
tools/perf/util/pmu.c | 30 ++++++----
3 files changed, 89 insertions(+), 43 deletions(-)

diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index db882f630f7e..edb3ae76777d 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -182,6 +182,38 @@ static int tp_event_has_id(const char *dir_path, struct dirent *evt_dir)

#define MAX_EVENT_LENGTH 512

+void parse_events__append_error(struct parse_events_error *err, int idx,
+ char *str, char *help)
+{
+ char *new_str = NULL;
+
+ if (WARN(!str, "WARNING: failed to provide error string")) {
+ free(help);
+ return;
+ }
+ if (err->str) {
+ int ret;
+
+ if (err->help) {
+ ret = asprintf(&new_str,
+ "%s (previous error: %s(help: %s))",
+ str, err->str, err->help);
+ } else {
+ ret = asprintf(&new_str,
+ "%s (previous error: %s)",
+ str, err->str);
+ }
+ if (ret < 0)
+ new_str = NULL;
+ else
+ zfree(&str);
+ }
+ err->idx = idx;
+ free(err->str);
+ err->str = new_str ?: str;
+ free(err->help);
+ err->help = help;
+}

struct tracepoint_path *tracepoint_id_to_path(u64 config)
{
@@ -932,11 +964,11 @@ static int check_type_val(struct parse_events_term *term,
return 0;

if (err) {
- err->idx = term->err_val;
- if (type == PARSE_EVENTS__TERM_TYPE_NUM)
- err->str = strdup("expected numeric value");
- else
- err->str = strdup("expected string value");
+ parse_events__append_error(err, term->err_val,
+ type == PARSE_EVENTS__TERM_TYPE_NUM
+ ? strdup("expected numeric value")
+ : strdup("expected string value"),
+ NULL);
}
return -EINVAL;
}
@@ -972,8 +1004,11 @@ static bool config_term_shrinked;
static bool
config_term_avail(int term_type, struct parse_events_error *err)
{
+ char *err_str;
+
if (term_type < 0 || term_type >= __PARSE_EVENTS__TERM_TYPE_NR) {
- err->str = strdup("Invalid term_type");
+ parse_events__append_error(err, -1,
+ strdup("Invalid term_type"), NULL);
return false;
}
if (!config_term_shrinked)
@@ -992,9 +1027,9 @@ config_term_avail(int term_type, struct parse_events_error *err)
return false;

/* term_type is validated so indexing is safe */
- if (asprintf(&err->str, "'%s' is not usable in 'perf stat'",
- config_term_names[term_type]) < 0)
- err->str = NULL;
+ if (asprintf(&err_str, "'%s' is not usable in 'perf stat'",
+ config_term_names[term_type]) >= 0)
+ parse_events__append_error(err, -1, err_str, NULL);
return false;
}
}
@@ -1036,17 +1071,20 @@ do { \
case PARSE_EVENTS__TERM_TYPE_BRANCH_SAMPLE_TYPE:
CHECK_TYPE_VAL(STR);
if (strcmp(term->val.str, "no") &&
- parse_branch_str(term->val.str, &attr->branch_sample_type)) {
- err->str = strdup("invalid branch sample type");
- err->idx = term->err_val;
+ parse_branch_str(term->val.str,
+ &attr->branch_sample_type)) {
+ parse_events__append_error(err, term->err_val,
+ strdup("invalid branch sample type"),
+ NULL);
return -EINVAL;
}
break;
case PARSE_EVENTS__TERM_TYPE_TIME:
CHECK_TYPE_VAL(NUM);
if (term->val.num > 1) {
- err->str = strdup("expected 0 or 1");
- err->idx = term->err_val;
+ parse_events__append_error(err, term->err_val,
+ strdup("expected 0 or 1"),
+ NULL);
return -EINVAL;
}
break;
@@ -1080,8 +1118,9 @@ do { \
case PARSE_EVENTS__TERM_TYPE_PERCORE:
CHECK_TYPE_VAL(NUM);
if ((unsigned int)term->val.num > 1) {
- err->str = strdup("expected 0 or 1");
- err->idx = term->err_val;
+ parse_events__append_error(err, term->err_val,
+ strdup("expected 0 or 1"),
+ NULL);
return -EINVAL;
}
break;
@@ -1089,9 +1128,9 @@ do { \
CHECK_TYPE_VAL(NUM);
break;
default:
- err->str = strdup("unknown term");
- err->idx = term->err_term;
- err->help = parse_events_formats_error_string(NULL);
+ parse_events__append_error(err, term->err_term,
+ strdup("unknown term"),
+ parse_events_formats_error_string(NULL));
return -EINVAL;
}

@@ -1142,9 +1181,9 @@ static int config_term_tracepoint(struct perf_event_attr *attr,
return config_term_common(attr, term, err);
default:
if (err) {
- err->idx = term->err_term;
- err->str = strdup("unknown term");
- err->help = strdup("valid terms: call-graph,stack-size\n");
+ parse_events__append_error(err, term->err_term,
+ strdup("unknown term"),
+ strdup("valid terms: call-graph,stack-size\n"));
}
return -EINVAL;
}
@@ -1323,10 +1362,12 @@ int parse_events_add_pmu(struct parse_events_state *parse_state,

pmu = perf_pmu__find(name);
if (!pmu) {
- if (asprintf(&err->str,
+ char *err_str;
+
+ if (asprintf(&err_str,
"Cannot find PMU `%s'. Missing kernel support?",
- name) < 0)
- err->str = NULL;
+ name) >= 0)
+ parse_events__append_error(err, -1, err_str, NULL);
return -EINVAL;
}

@@ -2797,13 +2838,10 @@ void parse_events__clear_array(struct parse_events_array *a)
void parse_events_evlist_error(struct parse_events_state *parse_state,
int idx, const char *str)
{
- struct parse_events_error *err = parse_state->error;
-
- if (!err)
+ if (!parse_state->error)
return;
- err->idx = idx;
- err->str = strdup(str);
- WARN_ONCE(!err->str, "WARNING: failed to allocate error string");
+
+ parse_events__append_error(parse_state->error, idx, strdup(str), NULL);
}

static void config_terms_list(char *buf, size_t buf_sz)
diff --git a/tools/perf/util/parse-events.h b/tools/perf/util/parse-events.h
index 769e07cddaa2..a7d42faeab0c 100644
--- a/tools/perf/util/parse-events.h
+++ b/tools/perf/util/parse-events.h
@@ -124,6 +124,8 @@ struct parse_events_state {
struct list_head *terms;
};

+void parse_events__append_error(struct parse_events_error *err, int idx,
+ char *str, char *help);
void parse_events__shrink_config_terms(void);
int parse_events__is_hardcoded_term(struct parse_events_term *term);
int parse_events_term__num(struct parse_events_term **term,
diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index adbe97e941dd..4015ec11944a 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -1050,9 +1050,9 @@ static int pmu_config_term(struct list_head *formats,
if (err) {
char *pmu_term = pmu_formats_string(formats);

- err->idx = term->err_term;
- err->str = strdup("unknown term");
- err->help = parse_events_formats_error_string(pmu_term);
+ parse_events__append_error(err, term->err_term,
+ strdup("unknown term"),
+ parse_events_formats_error_string(pmu_term));
free(pmu_term);
}
return -EINVAL;
@@ -1080,8 +1080,9 @@ static int pmu_config_term(struct list_head *formats,
if (term->no_value &&
bitmap_weight(format->bits, PERF_PMU_FORMAT_BITS) > 1) {
if (err) {
- err->idx = term->err_val;
- err->str = strdup("no value assigned for term");
+ parse_events__append_error(err, term->err_val,
+ strdup("no value assigned for term"),
+ NULL);
}
return -EINVAL;
}
@@ -1094,8 +1095,9 @@ static int pmu_config_term(struct list_head *formats,
term->config, term->val.str);
}
if (err) {
- err->idx = term->err_val;
- err->str = strdup("expected numeric value");
+ parse_events__append_error(err, term->err_val,
+ strdup("expected numeric value"),
+ NULL);
}
return -EINVAL;
}
@@ -1108,11 +1110,15 @@ static int pmu_config_term(struct list_head *formats,
max_val = pmu_format_max_value(format->bits);
if (val > max_val) {
if (err) {
- err->idx = term->err_val;
- if (asprintf(&err->str,
- "value too big for format, maximum is %llu",
- (unsigned long long)max_val) < 0)
- err->str = strdup("value too big for format");
+ char *err_str;
+
+ parse_events__append_error(err, term->err_val,
+ asprintf(&err_str,
+ "value too big for format, maximum is %llu",
+ (unsigned long long)max_val) < 0
+ ? strdup("value too big for format")
+ : err_str,
+ NULL);
return -EINVAL;
}
/*
--
2.23.0.866.gb869b98d4c-goog