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

Jiri Olsa
2019-10-25T07:58:35Z

On Thu, Oct 24, 2019 at 12:01:54PM -0700, Ian Rogers wrote:
> 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))

hum... I'd argue that the previous state was better:

[jolsa@krava perf]$ ./perf stat -e c/c/
event syntax error: 'c/c/'
\___ unknown term

jirka

>
> 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
>