linux-kernel - Re: [PATCH v2 2/6] perf test: Handle metric reuse in pmu-events parsing test

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Date:   Thu, 1 Apr 2021 15:49:40 +0200
From:   Jiri Olsa <jolsa@...hat.com>
To:     John Garry <john.garry@...wei.com>
Cc:     will@...nel.org, mathieu.poirier@...aro.org, leo.yan@...aro.org,
        peterz@...radead.org, mingo@...hat.com, acme@...nel.org,
        mark.rutland@....com, alexander.shishkin@...ux.intel.com,
        namhyung@...nel.org, irogers@...gle.com, linuxarm@...wei.com,
        kjain@...ux.ibm.com, kan.liang@...ux.intel.com,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        zhangshaokun@...ilicon.com, pc@...ibm.com
Subject: Re: [PATCH v2 2/6] perf test: Handle metric reuse in pmu-events
 parsing test

On Thu, Mar 25, 2021 at 06:33:14PM +0800, John Garry wrote:

SNIP

> +struct metric {
> +	struct list_head list;
> +	struct metric_ref metric_ref;
> +};
> +
> +static int resolve_metric_simple(struct expr_parse_ctx *pctx,
> +				 struct list_head *compound_list,
> +				 struct pmu_events_map *map,
> +				 const char *metric_name)
> +{
> +	struct hashmap_entry *cur, *cur_tmp;
> +	struct metric *metric, *tmp;
> +	size_t bkt;
> +	bool all;
> +	int rc;
> +
> +	do {
> +		all = true;
> +		hashmap__for_each_entry_safe((&pctx->ids), cur, cur_tmp, bkt) {
> +			struct metric_ref *ref;
> +			struct pmu_event *pe;
> +
> +			pe = metrcgroup_find_metric(cur->key, map);
> +			if (!pe)
> +				continue;
> +
> +			if (!strcmp(metric_name, (char *)cur->key)) {
> +				pr_warning("Recursion detected for metric %s\n", metric_name);
> +				rc = -1;
> +				goto out_err;
> +			}
> +
> +			all = false;
> +
> +			/* The metric key itself needs to go out.. */
> +			expr__del_id(pctx, cur->key);
> +
> +			metric = malloc(sizeof(*metric));
> +			if (!metric) {
> +				rc = -ENOMEM;
> +				goto out_err;
> +			}
> +
> +			ref = &metric->metric_ref;
> +			ref->metric_name = pe->metric_name;
> +			ref->metric_expr = pe->metric_expr;
> +			list_add_tail(&metric->list, compound_list);
> +
> +			rc = expr__find_other(pe->metric_expr, NULL, pctx, 0);

so this might add new items to pctx->ids, I think you need
to restart the iteration as we do it in __resolve_metric
otherwise you could miss some new keys

jirka

> +			if (rc)
> +				goto out_err;
> +		}
> +	} while (!all);
> +
> +	return 0;
> +
> +out_err:
> +	list_for_each_entry_safe(metric, tmp, compound_list, list)
> +		free(metric);
> +
> +	return rc;
> +
> +}

SNIP