Commit 38f83cc9 authored by Ian Rogers's avatar Ian Rogers Committed by Namhyung Kim
Browse files

perf top: Switch user option to use BPF filter 



Finding user processes by scanning /proc is inherently racy and
results in perf_event_open failures. Use a BPF filter to drop samples
where the uid doesn't match.

Signed-off-by: default avatarIan Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250604174545.2853620-7-irogers@google.com


Signed-off-by: default avatarNamhyung Kim <namhyung@kernel.org>
parent c54e2f82

tools/perf/builtin-top.c

+12 −10
Original line number Diff line number Diff line
@@ -643,7 +643,7 @@ static void *display_thread_tui(void *arg) 
	 */

	evlist__for_each_entry(top->evlist, pos) {

		struct hists *hists = evsel__hists(pos);

		hists->uid_filter_str = top->record_opts.target.uid_str;

		hists->uid_filter_str = top->uid_str;

	}



	ret = evlist__tui_browse_hists(top->evlist, help, &hbt, top->min_percent,
@@ -1571,7 +1571,7 @@ int cmd_top(int argc, const char **argv) 
		    "Add prefix to source file path names in programs (with --prefix-strip)"),

	OPT_STRING(0, "prefix-strip", &annotate_opts.prefix_strip, "N",

		    "Strip first N entries of source file path name in programs (with --prefix)"),

	OPT_STRING('u', "uid", &target->uid_str, "user", "user to profile"),

	OPT_STRING('u', "uid", &top.uid_str, "user", "user to profile"),

	OPT_CALLBACK(0, "percent-limit", &top, "percent",

		     "Don't show entries under that percent", parse_percent_limit),

	OPT_CALLBACK(0, "percentage", NULL, "relative|absolute",
@@ -1762,14 +1762,16 @@ int cmd_top(int argc, const char **argv) 
		ui__warning("%s\n", errbuf);

	}



	status = target__parse_uid(target);

	if (status) {

		int saved_errno = errno;



		target__strerror(target, status, errbuf, BUFSIZ);

		ui__error("%s\n", errbuf);

	if (top.uid_str) {

		uid_t uid = parse_uid(top.uid_str);



		status = -saved_errno;

		if (uid == UINT_MAX) {

			ui__error("Invalid User: %s", top.uid_str);

			status = -EINVAL;

			goto out_delete_evlist;

		}

		status = parse_uid_filter(top.evlist, uid);

		if (status)

			goto out_delete_evlist;

	}

tools/perf/util/top.c

+2 −2
Original line number Diff line number Diff line
@@ -88,9 +88,9 @@ size_t perf_top__header_snprintf(struct perf_top *top, char *bf, size_t size) 
	else if (target->tid)

		ret += SNPRINTF(bf + ret, size - ret, " (target_tid: %s",

				target->tid);

	else if (target->uid_str != NULL)

	else if (top->uid_str != NULL)

		ret += SNPRINTF(bf + ret, size - ret, " (uid: %s",

				target->uid_str);

				top->uid_str);

	else

		ret += SNPRINTF(bf + ret, size - ret, " (all");

tools/perf/util/top.h

+1 −0
Original line number Diff line number Diff line
@@ -48,6 +48,7 @@ struct perf_top { 
	const char	   *sym_filter;

	float		   min_percent;

	unsigned int	   nr_threads_synthesize;

	const char	   *uid_str;



	struct {

		struct ordered_events	*in;