[PATCH v2 00/12] Move uid filtering to BPF filters

[PATCH v2 00/12] Move uid filtering to BPF filters

[Ian Rogers]

Rather than scanning /proc and skipping PIDs based on their UIDs, use
BPF filters for uid filtering. The /proc scanning in thread_map is
racy as the PID may exit before the perf_event_open causing perf to
abort. BPF UID filters are more robust as they avoid the race. Add a
helper for commands that support UID filtering and wire up. Remove the
non-BPF UID filtering support given it doesn't work.

v2: Add a perf record uid test (Namhyung) and force setting
    system-wide for perf trace and perf record (Namhyung). Ensure the
    uid filter isn't set on tracepoint evsels.

v1: https://lore.kernel.org/lkml/20250111190143.1029906-1-irogers@google.com/

Ian Rogers (12):
  perf tests record: Cleanup improvements
  perf bench evlist-open-close: Reduce scope of 2 variables
  perf parse-events filter: Use evsel__find_pmu
  perf target: Separate parse_uid into its own function
  perf parse-events: Add parse_uid_filter helper
  perf record: Switch user option to use BPF filter
  perf tests record: Add basic uid filtering test
  perf top: Switch user option to use BPF filter
  perf trace: Switch user option to use BPF filter
  perf bench evlist-open-close: Switch user option to use BPF filter
  perf target: Remove uid from target
  perf thread_map: Remove uid options

 tools/perf/bench/evlist-open-close.c        | 76 ++++++++++++---------
 tools/perf/builtin-ftrace.c                 |  1 -
 tools/perf/builtin-kvm.c                    |  2 -
 tools/perf/builtin-record.c                 | 27 +++++---
 tools/perf/builtin-stat.c                   |  4 +-
 tools/perf/builtin-top.c                    | 22 +++---
 tools/perf/builtin-trace.c                  | 27 +++++---
 tools/perf/tests/backward-ring-buffer.c     |  1 -
 tools/perf/tests/event-times.c              |  8 +--
 tools/perf/tests/keep-tracking.c            |  2 +-
 tools/perf/tests/mmap-basic.c               |  2 +-
 tools/perf/tests/openat-syscall-all-cpus.c  |  2 +-
 tools/perf/tests/openat-syscall-tp-fields.c |  1 -
 tools/perf/tests/openat-syscall.c           |  2 +-
 tools/perf/tests/perf-record.c              |  1 -
 tools/perf/tests/perf-time-to-tsc.c         |  2 +-
 tools/perf/tests/shell/record.sh            | 36 ++++++++--
 tools/perf/tests/switch-tracking.c          |  2 +-
 tools/perf/tests/task-exit.c                |  1 -
 tools/perf/tests/thread-map.c               |  2 +-
 tools/perf/util/bpf-filter.c                |  2 +-
 tools/perf/util/evlist.c                    |  3 +-
 tools/perf/util/parse-events.c              | 33 ++++++---
 tools/perf/util/parse-events.h              |  1 +
 tools/perf/util/python.c                    | 10 +--
 tools/perf/util/target.c                    | 54 ++-------------
 tools/perf/util/target.h                    | 15 +---
 tools/perf/util/thread_map.c                | 32 +--------
 tools/perf/util/thread_map.h                |  6 +-
 tools/perf/util/top.c                       |  4 +-
 tools/perf/util/top.h                       |  1 +
 31 files changed, 178 insertions(+), 204 deletions(-)

-- 
2.49.0.604.gff1f9ca942-goog

[PATCH v2 01/12] perf tests record: Cleanup improvements

[Ian Rogers]

Remove the script output file. Add a trap debug message. Minor style
consistency changes.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/tests/shell/record.sh | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/tools/perf/tests/shell/record.sh b/tools/perf/tests/shell/record.sh
index ba8d873d3ca7..05d91a663fda 100755
--- a/tools/perf/tests/shell/record.sh
+++ b/tools/perf/tests/shell/record.sh
@@ -34,13 +34,15 @@ default_fd_limit=$(ulimit -Sn)
 min_fd_limit=$(($(getconf _NPROCESSORS_ONLN) * 16))
 
 cleanup() {
-  rm -rf "${perfdata}"
-  rm -rf "${perfdata}".old
+  rm -f "${perfdata}"
+  rm -f "${perfdata}".old
+  rm -f "${script_output}"
 
   trap - EXIT TERM INT
 }
 
 trap_cleanup() {
+  echo "Unexpected signal in ${FUNCNAME[1]}"
   cleanup
   exit 1
 }
@@ -239,7 +241,7 @@ test_leader_sampling() {
     return
   fi
   index=0
-  perf script -i "${perfdata}" > $script_output
+  perf script -i "${perfdata}" > "${script_output}"
   while IFS= read -r line
   do
     # Check if the two instruction counts are equal in each record
@@ -252,7 +254,7 @@ test_leader_sampling() {
     fi
     index=$(($index+1))
     prev_cycles=$cycles
-  done < $script_output
+  done < "${script_output}"
   echo "Basic leader sampling test [Success]"
 }
 
-- 
2.49.0.604.gff1f9ca942-goog

[PATCH v2 02/12] perf bench evlist-open-close: Reduce scope of 2 variables

[Ian Rogers]

Make 2 global variables local. Reduces ELF binary size by removing
relocations. For a no flags build, the perf binary size is reduced by
4,144 bytes on x86-64.

Signed-off-by: Ian Rogers <irogers@google.com>
Reviewed-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/bench/evlist-open-close.c | 42 +++++++++++++++-------------
 1 file changed, 23 insertions(+), 19 deletions(-)

diff --git a/tools/perf/bench/evlist-open-close.c b/tools/perf/bench/evlist-open-close.c
index 5a27691469ed..79cedcf94a39 100644
--- a/tools/perf/bench/evlist-open-close.c
+++ b/tools/perf/bench/evlist-open-close.c
@@ -46,25 +46,6 @@ static struct record_opts opts = {
 	.ctl_fd_ack          = -1,
 };
 
-static const struct option options[] = {
-	OPT_STRING('e', "event", &event_string, "event", "event selector. use 'perf list' to list available events"),
-	OPT_INTEGER('n', "nr-events", &nr_events,
-		     "number of dummy events to create (default 1). If used with -e, it clones those events n times (1 = no change)"),
-	OPT_INTEGER('i', "iterations", &iterations, "Number of iterations used to compute average (default=100)"),
-	OPT_BOOLEAN('a', "all-cpus", &opts.target.system_wide, "system-wide collection from all CPUs"),
-	OPT_STRING('C', "cpu", &opts.target.cpu_list, "cpu", "list of cpus where to open events"),
-	OPT_STRING('p', "pid", &opts.target.pid, "pid", "record events on existing process id"),
-	OPT_STRING('t', "tid", &opts.target.tid, "tid", "record events on existing thread id"),
-	OPT_STRING('u', "uid", &opts.target.uid_str, "user", "user to profile"),
-	OPT_BOOLEAN(0, "per-thread", &opts.target.per_thread, "use per-thread mmaps"),
-	OPT_END()
-};
-
-static const char *const bench_usage[] = {
-	"perf bench internals evlist-open-close <options>",
-	NULL
-};
-
 static int evlist__count_evsel_fds(struct evlist *evlist)
 {
 	struct evsel *evsel;
@@ -225,6 +206,29 @@ static char *bench__repeat_event_string(const char *evstr, int n)
 
 int bench_evlist_open_close(int argc, const char **argv)
 {
+	const struct option options[] = {
+		OPT_STRING('e', "event", &event_string, "event",
+			   "event selector. use 'perf list' to list available events"),
+		OPT_INTEGER('n', "nr-events", &nr_events,
+			    "number of dummy events to create (default 1). If used with -e, it clones those events n times (1 = no change)"),
+		OPT_INTEGER('i', "iterations", &iterations,
+			    "Number of iterations used to compute average (default=100)"),
+		OPT_BOOLEAN('a', "all-cpus", &opts.target.system_wide,
+			    "system-wide collection from all CPUs"),
+		OPT_STRING('C', "cpu", &opts.target.cpu_list, "cpu",
+			   "list of cpus where to open events"),
+		OPT_STRING('p', "pid", &opts.target.pid, "pid",
+			   "record events on existing process id"),
+		OPT_STRING('t', "tid", &opts.target.tid, "tid",
+			   "record events on existing thread id"),
+		OPT_STRING('u', "uid", &opts.target.uid_str, "user", "user to profile"),
+		OPT_BOOLEAN(0, "per-thread", &opts.target.per_thread, "use per-thread mmaps"),
+		OPT_END()
+	};
+	const char *const bench_usage[] = {
+		"perf bench internals evlist-open-close <options>",
+		NULL
+	};
 	char *evstr, errbuf[BUFSIZ];
 	int err;
 
-- 
2.49.0.604.gff1f9ca942-goog

[PATCH v2 03/12] perf parse-events filter: Use evsel__find_pmu

[Ian Rogers]

Rather than manually scanning PMUs, use evsel__find_pmu that can use
the PMU set during event parsing.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/util/parse-events.c | 14 ++++----------
 1 file changed, 4 insertions(+), 10 deletions(-)

diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index 5152fd5a6ead..ad5b40843b18 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -2459,9 +2459,8 @@ foreach_evsel_in_last_glob(struct evlist *evlist,
 static int set_filter(struct evsel *evsel, const void *arg)
 {
 	const char *str = arg;
-	bool found = false;
 	int nr_addr_filters = 0;
-	struct perf_pmu *pmu = NULL;
+	struct perf_pmu *pmu;
 
 	if (evsel == NULL) {
 		fprintf(stderr,
@@ -2479,16 +2478,11 @@ static int set_filter(struct evsel *evsel, const void *arg)
 		return 0;
 	}
 
-	while ((pmu = perf_pmus__scan(pmu)) != NULL)
-		if (pmu->type == evsel->core.attr.type) {
-			found = true;
-			break;
-		}
-
-	if (found)
+	pmu = evsel__find_pmu(evsel);
+	if (pmu) {
 		perf_pmu__scan_file(pmu, "nr_addr_filters",
 				    "%d", &nr_addr_filters);
-
+	}
 	if (!nr_addr_filters)
 		return perf_bpf_filter__parse(&evsel->bpf_filters, str);
 
-- 
2.49.0.604.gff1f9ca942-goog

[PATCH v2 04/12] perf target: Separate parse_uid into its own function

[Ian Rogers]

Allow parse_uid to be called without a struct target. Rather than have
two errors, remove TARGET_ERRNO__USER_NOT_FOUND and use
TARGET_ERRNO__INVALID_UID as the handling is identical.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/util/target.c | 22 ++++++++++++----------
 tools/perf/util/target.h |  3 ++-
 2 files changed, 14 insertions(+), 11 deletions(-)

diff --git a/tools/perf/util/target.c b/tools/perf/util/target.c
index 0f383418e3df..f3ad59ccfa99 100644
--- a/tools/perf/util/target.c
+++ b/tools/perf/util/target.c
@@ -94,15 +94,13 @@ enum target_errno target__validate(struct target *target)
 	return ret;
 }
 
-enum target_errno target__parse_uid(struct target *target)
+uid_t parse_uid(const char *str)
 {
 	struct passwd pwd, *result;
 	char buf[1024];
-	const char *str = target->uid_str;
 
-	target->uid = UINT_MAX;
 	if (str == NULL)
-		return TARGET_ERRNO__SUCCESS;
+		return UINT_MAX;
 
 	/* Try user name first */
 	getpwnam_r(str, &pwd, buf, sizeof(buf), &result);
@@ -115,16 +113,22 @@ enum target_errno target__parse_uid(struct target *target)
 		int uid = strtol(str, &endptr, 10);
 
 		if (*endptr != '\0')
-			return TARGET_ERRNO__INVALID_UID;
+			return UINT_MAX;
 
 		getpwuid_r(uid, &pwd, buf, sizeof(buf), &result);
 
 		if (result == NULL)
-			return TARGET_ERRNO__USER_NOT_FOUND;
+			return UINT_MAX;
 	}
 
-	target->uid = result->pw_uid;
-	return TARGET_ERRNO__SUCCESS;
+	return result->pw_uid;
+}
+
+enum target_errno target__parse_uid(struct target *target)
+{
+	target->uid = parse_uid(target->uid_str);
+
+	return target->uid != UINT_MAX ? TARGET_ERRNO__SUCCESS : TARGET_ERRNO__INVALID_UID;
 }
 
 /*
@@ -142,7 +146,6 @@ static const char *target__error_str[] = {
 	"BPF switch overriding UID",
 	"BPF switch overriding THREAD",
 	"Invalid User: %s",
-	"Problems obtaining information for user %s",
 };
 
 int target__strerror(struct target *target, int errnum,
@@ -171,7 +174,6 @@ int target__strerror(struct target *target, int errnum,
 		break;
 
 	case TARGET_ERRNO__INVALID_UID:
-	case TARGET_ERRNO__USER_NOT_FOUND:
 		snprintf(buf, buflen, msg, target->uid_str);
 		break;
 
diff --git a/tools/perf/util/target.h b/tools/perf/util/target.h
index 2ee2cc30340f..e082bda990fb 100644
--- a/tools/perf/util/target.h
+++ b/tools/perf/util/target.h
@@ -48,12 +48,13 @@ enum target_errno {
 
 	/* for target__parse_uid() */
 	TARGET_ERRNO__INVALID_UID,
-	TARGET_ERRNO__USER_NOT_FOUND,
 
 	__TARGET_ERRNO__END,
 };
 
 enum target_errno target__validate(struct target *target);
+
+uid_t parse_uid(const char *str);
 enum target_errno target__parse_uid(struct target *target);
 
 int target__strerror(struct target *target, int errnum, char *buf, size_t buflen);
-- 
2.49.0.604.gff1f9ca942-goog

[PATCH v2 05/12] perf parse-events: Add parse_uid_filter helper

[Ian Rogers]

Add parse_uid_filter filter as a helper to parse_filter, that
constructs a uid filter string. As uid filters don't work with
tracepoint filters, add a is_possible_tp_filter function so the
tracepoint filter isn't attempted for tracepoint evsels.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/util/parse-events.c | 19 ++++++++++++++++++-
 tools/perf/util/parse-events.h |  1 +
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index ad5b40843b18..08ade3d70bc1 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -2456,6 +2456,12 @@ foreach_evsel_in_last_glob(struct evlist *evlist,
 	return 0;
 }
 
+/* Will a tracepoint filter work for str or should a BPF filter be used? */
+static bool is_possible_tp_filter(const char *str)
+{
+	return strstr(str, "uid") == NULL;
+}
+
 static int set_filter(struct evsel *evsel, const void *arg)
 {
 	const char *str = arg;
@@ -2468,7 +2474,7 @@ static int set_filter(struct evsel *evsel, const void *arg)
 		return -1;
 	}
 
-	if (evsel->core.attr.type == PERF_TYPE_TRACEPOINT) {
+	if (evsel->core.attr.type == PERF_TYPE_TRACEPOINT && is_possible_tp_filter(str)) {
 		if (evsel__append_tp_filter(evsel, str) < 0) {
 			fprintf(stderr,
 				"not enough memory to hold filter string\n");
@@ -2504,6 +2510,17 @@ int parse_filter(const struct option *opt, const char *str,
 					  (const void *)str);
 }
 
+int parse_uid_filter(struct evlist *evlist, uid_t uid)
+{
+	struct option opt = {
+		.value = &evlist,
+	};
+	char buf[128];
+
+	snprintf(buf, sizeof(buf), "uid == %d", uid);
+	return parse_filter(&opt, buf, /*unset=*/0);
+}
+
 static int add_exclude_perf_filter(struct evsel *evsel,
 				   const void *arg __maybe_unused)
 {
diff --git a/tools/perf/util/parse-events.h b/tools/perf/util/parse-events.h
index e176a34ab088..289afd42d642 100644
--- a/tools/perf/util/parse-events.h
+++ b/tools/perf/util/parse-events.h
@@ -45,6 +45,7 @@ static inline int parse_events(struct evlist *evlist, const char *str,
 int parse_event(struct evlist *evlist, const char *str);
 
 int parse_filter(const struct option *opt, const char *str, int unset);
+int parse_uid_filter(struct evlist *evlist, uid_t uid);
 int exclude_perf(const struct option *opt, const char *arg, int unset);
 
 enum parse_events__term_val_type {
-- 
2.49.0.604.gff1f9ca942-goog

[PATCH v2 06/12] perf record: Switch user option to use BPF filter

[Ian Rogers]

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. Ensure adding the BPF filter forces
system-wide.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/builtin-record.c | 27 ++++++++++++++++-----------
 1 file changed, 16 insertions(+), 11 deletions(-)

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index ba20bf7c011d..202c917fd122 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -173,6 +173,7 @@ struct record {
 	bool			timestamp_boundary;
 	bool			off_cpu;
 	const char		*filter_action;
+	const char		*uid_str;
 	struct switch_output	switch_output;
 	unsigned long long	samples;
 	unsigned long		output_max_size;	/* = 0: unlimited */
@@ -3460,8 +3461,7 @@ static struct option __record_options[] = {
 		     "or ranges of time to enable events e.g. '-D 10-20,30-40'",
 		     record__parse_event_enable_time),
 	OPT_BOOLEAN(0, "kcore", &record.opts.kcore, "copy /proc/kcore"),
-	OPT_STRING('u', "uid", &record.opts.target.uid_str, "user",
-		   "user to profile"),
+	OPT_STRING('u', "uid", &record.uid_str, "user", "user to profile"),
 
 	OPT_CALLBACK_NOOPT('b', "branch-any", &record.opts.branch_stack,
 		     "branch any", "sample any taken branches",
@@ -4196,19 +4196,24 @@ int cmd_record(int argc, const char **argv)
 		ui__warning("%s\n", errbuf);
 	}
 
-	err = target__parse_uid(&rec->opts.target);
-	if (err) {
-		int saved_errno = errno;
+	if (rec->uid_str) {
+		uid_t uid = parse_uid(rec->uid_str);
 
-		target__strerror(&rec->opts.target, err, errbuf, BUFSIZ);
-		ui__error("%s", errbuf);
+		if (uid == UINT_MAX) {
+			ui__error("Invalid User: %s", rec->uid_str);
+			err = -EINVAL;
+			goto out;
+		}
+		err = parse_uid_filter(rec->evlist, uid);
+		if (err)
+			goto out;
 
-		err = -saved_errno;
-		goto out;
+		/* User ID filtering implies system wide. */
+		rec->opts.target.system_wide = true;
 	}
 
-	/* Enable ignoring missing threads when -u/-p option is defined. */
-	rec->opts.ignore_missing_thread = rec->opts.target.uid != UINT_MAX || rec->opts.target.pid;
+	/* Enable ignoring missing threads when -p option is defined. */
+	rec->opts.ignore_missing_thread = rec->opts.target.pid;
 
 	evlist__warn_user_requested_cpus(rec->evlist, rec->opts.target.cpu_list);
 
-- 
2.49.0.604.gff1f9ca942-goog

[PATCH v2 07/12] perf tests record: Add basic uid filtering test

[Ian Rogers]

Based on the system-wide test with changes around how failure is
handled as BPF permissions are a bigger issue than perf event
paranoia.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/tests/shell/record.sh | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/tools/perf/tests/shell/record.sh b/tools/perf/tests/shell/record.sh
index 05d91a663fda..308916f9c292 100755
--- a/tools/perf/tests/shell/record.sh
+++ b/tools/perf/tests/shell/record.sh
@@ -231,6 +231,31 @@ test_cgroup() {
   echo "Cgroup sampling test [Success]"
 }
 
+test_uid() {
+  echo "Uid sampling test"
+  if ! perf record -aB --synth=no --uid "$(id -u)" -o "${perfdata}" ${testprog} \
+    > "${script_output}" 2>&1
+  then
+    if grep -q "libbpf.*EPERM" "${script_output}"
+    then
+      echo "Uid sampling [Skipped permissions]"
+      return
+    else
+      echo "Uid sampling [Failed to record]"
+      err=1
+      # cat "${script_output}"
+      return
+    fi
+  fi
+  if ! perf report -i "${perfdata}" -q | grep -q "${testsym}"
+  then
+    echo "Uid sampling [Failed missing output]"
+    err=1
+    return
+  fi
+  echo "Uid sampling test [Success]"
+}
+
 test_leader_sampling() {
   echo "Basic leader sampling test"
   if ! perf record -o "${perfdata}" -e "{cycles,cycles}:Su" -- \
@@ -324,6 +349,7 @@ test_system_wide
 test_workload
 test_branch_counter
 test_cgroup
+test_uid
 test_leader_sampling
 test_topdown_leader_sampling
 test_precise_max
-- 
2.49.0.604.gff1f9ca942-goog

[PATCH v2 08/12] perf top: Switch user option to use BPF filter

[Ian Rogers]

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: Ian Rogers <irogers@google.com>
---
 tools/perf/builtin-top.c | 22 ++++++++++++----------
 tools/perf/util/top.c    |  4 ++--
 tools/perf/util/top.h    |  1 +
 3 files changed, 15 insertions(+), 12 deletions(-)

diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 1061f4eebc3f..9a7af69b7c73 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -642,7 +642,7 @@ 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,
@@ -1566,7 +1566,7 @@ 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",
@@ -1757,15 +1757,17 @@ 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;
-		goto out_delete_evlist;
+		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;
 	}
 
 	if (target__none(target))
diff --git a/tools/perf/util/top.c b/tools/perf/util/top.c
index 4db3d1bd686c..b06e10a116bb 100644
--- a/tools/perf/util/top.c
+++ b/tools/perf/util/top.c
@@ -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");
 
diff --git a/tools/perf/util/top.h b/tools/perf/util/top.h
index 4c5588dbb131..04ff926846be 100644
--- a/tools/perf/util/top.h
+++ b/tools/perf/util/top.h
@@ -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;
-- 
2.49.0.604.gff1f9ca942-goog

[PATCH v2 09/12] perf trace: Switch user option to use BPF filter

[Ian Rogers]

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. Ensure adding the BPF filter forces
system-wide.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/builtin-trace.c | 26 +++++++++++++++++---------
 1 file changed, 17 insertions(+), 9 deletions(-)

diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 6ac51925ea42..1f7d2b3d8b3d 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -240,6 +240,7 @@ struct trace {
 		struct ordered_events	data;
 		u64			last;
 	} oe;
+	const char		*uid_str;
 };
 
 static void trace__load_vmlinux_btf(struct trace *trace __maybe_unused)
@@ -4401,8 +4402,8 @@ static int trace__run(struct trace *trace, int argc, const char **argv)
 		evlist__add(evlist, pgfault_min);
 	}
 
-	/* Enable ignoring missing threads when -u/-p option is defined. */
-	trace->opts.ignore_missing_thread = trace->opts.target.uid != UINT_MAX || trace->opts.target.pid;
+	/* Enable ignoring missing threads when -p option is defined. */
+	trace->opts.ignore_missing_thread = trace->opts.target.pid;
 
 	if (trace->sched &&
 	    evlist__add_newtp(evlist, "sched", "sched_stat_runtime", trace__sched_stat_runtime))
@@ -5420,8 +5421,7 @@ int cmd_trace(int argc, const char **argv)
 		    "child tasks do not inherit counters"),
 	OPT_CALLBACK('m', "mmap-pages", &trace.opts.mmap_pages, "pages",
 		     "number of mmap data pages", evlist__parse_mmap_pages),
-	OPT_STRING('u', "uid", &trace.opts.target.uid_str, "user",
-		   "user to profile"),
+	OPT_STRING('u', "uid", &trace.uid_str, "user", "user to profile"),
 	OPT_CALLBACK(0, "duration", &trace, "float",
 		     "show only events with duration > N.M ms",
 		     trace__set_duration),
@@ -5762,11 +5762,19 @@ int cmd_trace(int argc, const char **argv)
 		goto out_close;
 	}
 
-	err = target__parse_uid(&trace.opts.target);
-	if (err) {
-		target__strerror(&trace.opts.target, err, bf, sizeof(bf));
-		fprintf(trace.output, "%s", bf);
-		goto out_close;
+	if (trace.uid_str) {
+		uid_t uid = parse_uid(trace.uid_str);
+
+		if (uid == UINT_MAX) {
+			ui__error("Invalid User: %s", trace.uid_str);
+			err = -EINVAL;
+			goto out_close;
+		}
+		err = parse_uid_filter(trace.evlist, uid);
+		if (err)
+			goto out_close;
+
+		trace.opts.target.system_wide = true;
 	}
 
 	if (!argc && target__none(&trace.opts.target))
-- 
2.49.0.604.gff1f9ca942-goog

[PATCH v2 10/12] perf bench evlist-open-close: Switch user option to use BPF filter

[Ian Rogers]

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: Ian Rogers <irogers@google.com>
---
 tools/perf/bench/evlist-open-close.c | 36 ++++++++++++++++------------
 1 file changed, 21 insertions(+), 15 deletions(-)

diff --git a/tools/perf/bench/evlist-open-close.c b/tools/perf/bench/evlist-open-close.c
index 79cedcf94a39..bfaf50e4e519 100644
--- a/tools/perf/bench/evlist-open-close.c
+++ b/tools/perf/bench/evlist-open-close.c
@@ -57,7 +57,7 @@ static int evlist__count_evsel_fds(struct evlist *evlist)
 	return cnt;
 }
 
-static struct evlist *bench__create_evlist(char *evstr)
+static struct evlist *bench__create_evlist(char *evstr, const char *uid_str)
 {
 	struct parse_events_error err;
 	struct evlist *evlist = evlist__new();
@@ -78,6 +78,18 @@ static struct evlist *bench__create_evlist(char *evstr)
 		goto out_delete_evlist;
 	}
 	parse_events_error__exit(&err);
+	if (uid_str) {
+		uid_t uid = parse_uid(uid_str);
+
+		if (uid == UINT_MAX) {
+			pr_err("Invalid User: %s", uid_str);
+			ret = -EINVAL;
+			goto out_delete_evlist;
+		}
+		ret = parse_uid_filter(evlist, uid);
+		if (ret)
+			goto out_delete_evlist;
+	}
 	ret = evlist__create_maps(evlist, &opts.target);
 	if (ret < 0) {
 		pr_err("Not enough memory to create thread/cpu maps\n");
@@ -117,10 +129,10 @@ static int bench__do_evlist_open_close(struct evlist *evlist)
 	return 0;
 }
 
-static int bench_evlist_open_close__run(char *evstr)
+static int bench_evlist_open_close__run(char *evstr, const char *uid_str)
 {
 	// used to print statistics only
-	struct evlist *evlist = bench__create_evlist(evstr);
+	struct evlist *evlist = bench__create_evlist(evstr, uid_str);
 	double time_average, time_stddev;
 	struct timeval start, end, diff;
 	struct stats time_stats;
@@ -142,7 +154,7 @@ static int bench_evlist_open_close__run(char *evstr)
 
 	for (i = 0; i < iterations; i++) {
 		pr_debug("Started iteration %d\n", i);
-		evlist = bench__create_evlist(evstr);
+		evlist = bench__create_evlist(evstr, uid_str);
 		if (!evlist)
 			return -ENOMEM;
 
@@ -206,6 +218,7 @@ static char *bench__repeat_event_string(const char *evstr, int n)
 
 int bench_evlist_open_close(int argc, const char **argv)
 {
+	const char *uid_str = NULL;
 	const struct option options[] = {
 		OPT_STRING('e', "event", &event_string, "event",
 			   "event selector. use 'perf list' to list available events"),
@@ -221,7 +234,7 @@ int bench_evlist_open_close(int argc, const char **argv)
 			   "record events on existing process id"),
 		OPT_STRING('t', "tid", &opts.target.tid, "tid",
 			   "record events on existing thread id"),
-		OPT_STRING('u', "uid", &opts.target.uid_str, "user", "user to profile"),
+		OPT_STRING('u', "uid", &uid_str, "user", "user to profile"),
 		OPT_BOOLEAN(0, "per-thread", &opts.target.per_thread, "use per-thread mmaps"),
 		OPT_END()
 	};
@@ -245,15 +258,8 @@ int bench_evlist_open_close(int argc, const char **argv)
 		goto out;
 	}
 
-	err = target__parse_uid(&opts.target);
-	if (err) {
-		target__strerror(&opts.target, err, errbuf, sizeof(errbuf));
-		pr_err("%s", errbuf);
-		goto out;
-	}
-
-	/* Enable ignoring missing threads when -u/-p option is defined. */
-	opts.ignore_missing_thread = opts.target.uid != UINT_MAX || opts.target.pid;
+	/* Enable ignoring missing threads when -p option is defined. */
+	opts.ignore_missing_thread = opts.target.pid;
 
 	evstr = bench__repeat_event_string(event_string, nr_events);
 	if (!evstr) {
@@ -261,7 +267,7 @@ int bench_evlist_open_close(int argc, const char **argv)
 		goto out;
 	}
 
-	err = bench_evlist_open_close__run(evstr);
+	err = bench_evlist_open_close__run(evstr, uid_str);
 
 	free(evstr);
 out:
-- 
2.49.0.604.gff1f9ca942-goog

[PATCH v2 11/12] perf target: Remove uid from target

[Ian Rogers]

Gathering threads with a uid by scanning /proc is inherently racy
leading to perf_event_open failures that quit perf. All users of the
functionality now use BPF filters, so remove uid and uid_str from
target.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/builtin-ftrace.c                 |  1 -
 tools/perf/builtin-kvm.c                    |  2 -
 tools/perf/builtin-stat.c                   |  4 +-
 tools/perf/builtin-trace.c                  |  1 -
 tools/perf/tests/backward-ring-buffer.c     |  1 -
 tools/perf/tests/event-times.c              |  4 +-
 tools/perf/tests/openat-syscall-tp-fields.c |  1 -
 tools/perf/tests/perf-record.c              |  1 -
 tools/perf/tests/task-exit.c                |  1 -
 tools/perf/util/bpf-filter.c                |  2 +-
 tools/perf/util/evlist.c                    |  3 +-
 tools/perf/util/target.c                    | 46 +--------------------
 tools/perf/util/target.h                    | 12 +-----
 13 files changed, 6 insertions(+), 73 deletions(-)

diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c
index 7caa18d5ffc3..ae901f2a18ef 100644
--- a/tools/perf/builtin-ftrace.c
+++ b/tools/perf/builtin-ftrace.c
@@ -1590,7 +1590,6 @@ int cmd_ftrace(int argc, const char **argv)
 	int (*cmd_func)(struct perf_ftrace *) = NULL;
 	struct perf_ftrace ftrace = {
 		.tracer = DEFAULT_TRACER,
-		.target = { .uid = UINT_MAX, },
 	};
 	const struct option common_options[] = {
 	OPT_STRING('p', "pid", &ftrace.target.pid, "pid",
diff --git a/tools/perf/builtin-kvm.c b/tools/perf/builtin-kvm.c
index 67fd2b006b0b..d75bd3684980 100644
--- a/tools/perf/builtin-kvm.c
+++ b/tools/perf/builtin-kvm.c
@@ -1871,8 +1871,6 @@ static int kvm_events_live(struct perf_kvm_stat *kvm,
 	kvm->opts.user_interval = 1;
 	kvm->opts.mmap_pages = 512;
 	kvm->opts.target.uses_mmap = false;
-	kvm->opts.target.uid_str = NULL;
-	kvm->opts.target.uid = UINT_MAX;
 
 	symbol__init(NULL);
 	disable_buildid_cache();
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 68ea7589c143..22ec1d0702e7 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -108,9 +108,7 @@ static struct parse_events_option_args parse_events_option_args = {
 
 static bool all_counters_use_bpf = true;
 
-static struct target target = {
-	.uid	= UINT_MAX,
-};
+static struct target target;
 
 static volatile sig_atomic_t	child_pid			= -1;
 static int			detailed_run			=  0;
diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 1f7d2b3d8b3d..aa0a27dd7d21 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -5374,7 +5374,6 @@ int cmd_trace(int argc, const char **argv)
 	struct trace trace = {
 		.opts = {
 			.target = {
-				.uid	   = UINT_MAX,
 				.uses_mmap = true,
 			},
 			.user_freq     = UINT_MAX,
diff --git a/tools/perf/tests/backward-ring-buffer.c b/tools/perf/tests/backward-ring-buffer.c
index 79a980b1e786..c5e7999f2817 100644
--- a/tools/perf/tests/backward-ring-buffer.c
+++ b/tools/perf/tests/backward-ring-buffer.c
@@ -91,7 +91,6 @@ static int test__backward_ring_buffer(struct test_suite *test __maybe_unused, in
 	struct parse_events_error parse_error;
 	struct record_opts opts = {
 		.target = {
-			.uid = UINT_MAX,
 			.uses_mmap = true,
 		},
 		.freq	      = 0,
diff --git a/tools/perf/tests/event-times.c b/tools/perf/tests/event-times.c
index deefe5003bfc..2148024b4f4a 100644
--- a/tools/perf/tests/event-times.c
+++ b/tools/perf/tests/event-times.c
@@ -17,9 +17,7 @@
 static int attach__enable_on_exec(struct evlist *evlist)
 {
 	struct evsel *evsel = evlist__last(evlist);
-	struct target target = {
-		.uid = UINT_MAX,
-	};
+	struct target target = {};
 	const char *argv[] = { "true", NULL, };
 	char sbuf[STRERR_BUFSIZE];
 	int err;
diff --git a/tools/perf/tests/openat-syscall-tp-fields.c b/tools/perf/tests/openat-syscall-tp-fields.c
index 0ef4ba7c1571..2a139d2781a8 100644
--- a/tools/perf/tests/openat-syscall-tp-fields.c
+++ b/tools/perf/tests/openat-syscall-tp-fields.c
@@ -28,7 +28,6 @@ static int test__syscall_openat_tp_fields(struct test_suite *test __maybe_unused
 {
 	struct record_opts opts = {
 		.target = {
-			.uid = UINT_MAX,
 			.uses_mmap = true,
 		},
 		.no_buffering = true,
diff --git a/tools/perf/tests/perf-record.c b/tools/perf/tests/perf-record.c
index 0958c7c8995f..0b3c37e66871 100644
--- a/tools/perf/tests/perf-record.c
+++ b/tools/perf/tests/perf-record.c
@@ -45,7 +45,6 @@ static int test__PERF_RECORD(struct test_suite *test __maybe_unused, int subtest
 {
 	struct record_opts opts = {
 		.target = {
-			.uid = UINT_MAX,
 			.uses_mmap = true,
 		},
 		.no_buffering = true,
diff --git a/tools/perf/tests/task-exit.c b/tools/perf/tests/task-exit.c
index 8e328bbd509d..4053ff2813bb 100644
--- a/tools/perf/tests/task-exit.c
+++ b/tools/perf/tests/task-exit.c
@@ -46,7 +46,6 @@ static int test__task_exit(struct test_suite *test __maybe_unused, int subtest _
 	struct evsel *evsel;
 	struct evlist *evlist;
 	struct target target = {
-		.uid		= UINT_MAX,
 		.uses_mmap	= true,
 	};
 	const char *argv[] = { "true", NULL };
diff --git a/tools/perf/util/bpf-filter.c b/tools/perf/util/bpf-filter.c
index a4fdf6911ec1..ed4845ff4a10 100644
--- a/tools/perf/util/bpf-filter.c
+++ b/tools/perf/util/bpf-filter.c
@@ -449,7 +449,7 @@ int perf_bpf_filter__prepare(struct evsel *evsel, struct target *target)
 	struct bpf_program *prog;
 	struct bpf_link *link;
 	struct perf_bpf_filter_entry *entry;
-	bool needs_idx_hash = !target__has_cpu(target) && !target->uid_str;
+	bool needs_idx_hash = !target__has_cpu(target);
 
 	entry = calloc(MAX_FILTERS, sizeof(*entry));
 	if (entry == NULL)
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index c1a04141aed0..2e1f14bc8461 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -1006,8 +1006,7 @@ int evlist__create_maps(struct evlist *evlist, struct target *target)
 	 * per-thread data. thread_map__new_str will call
 	 * thread_map__new_all_cpus to enumerate all threads.
 	 */
-	threads = thread_map__new_str(target->pid, target->tid, target->uid,
-				      all_threads);
+	threads = thread_map__new_str(target->pid, target->tid, UINT_MAX, all_threads);
 
 	if (!threads)
 		return -1;
diff --git a/tools/perf/util/target.c b/tools/perf/util/target.c
index f3ad59ccfa99..8cf71bea295a 100644
--- a/tools/perf/util/target.c
+++ b/tools/perf/util/target.c
@@ -28,20 +28,6 @@ enum target_errno target__validate(struct target *target)
 			ret = TARGET_ERRNO__PID_OVERRIDE_CPU;
 	}
 
-	/* UID and PID are mutually exclusive */
-	if (target->tid && target->uid_str) {
-		target->uid_str = NULL;
-		if (ret == TARGET_ERRNO__SUCCESS)
-			ret = TARGET_ERRNO__PID_OVERRIDE_UID;
-	}
-
-	/* UID and CPU are mutually exclusive */
-	if (target->uid_str && target->cpu_list) {
-		target->cpu_list = NULL;
-		if (ret == TARGET_ERRNO__SUCCESS)
-			ret = TARGET_ERRNO__UID_OVERRIDE_CPU;
-	}
-
 	/* PID and SYSTEM are mutually exclusive */
 	if (target->tid && target->system_wide) {
 		target->system_wide = false;
@@ -49,13 +35,6 @@ enum target_errno target__validate(struct target *target)
 			ret = TARGET_ERRNO__PID_OVERRIDE_SYSTEM;
 	}
 
-	/* UID and SYSTEM are mutually exclusive */
-	if (target->uid_str && target->system_wide) {
-		target->system_wide = false;
-		if (ret == TARGET_ERRNO__SUCCESS)
-			ret = TARGET_ERRNO__UID_OVERRIDE_SYSTEM;
-	}
-
 	/* BPF and CPU are mutually exclusive */
 	if (target->bpf_str && target->cpu_list) {
 		target->cpu_list = NULL;
@@ -70,13 +49,6 @@ enum target_errno target__validate(struct target *target)
 			ret = TARGET_ERRNO__BPF_OVERRIDE_PID;
 	}
 
-	/* BPF and UID are mutually exclusive */
-	if (target->bpf_str && target->uid_str) {
-		target->uid_str = NULL;
-		if (ret == TARGET_ERRNO__SUCCESS)
-			ret = TARGET_ERRNO__BPF_OVERRIDE_UID;
-	}
-
 	/* BPF and THREADS are mutually exclusive */
 	if (target->bpf_str && target->per_thread) {
 		target->per_thread = false;
@@ -124,31 +96,19 @@ uid_t parse_uid(const char *str)
 	return result->pw_uid;
 }
 
-enum target_errno target__parse_uid(struct target *target)
-{
-	target->uid = parse_uid(target->uid_str);
-
-	return target->uid != UINT_MAX ? TARGET_ERRNO__SUCCESS : TARGET_ERRNO__INVALID_UID;
-}
-
 /*
  * This must have a same ordering as the enum target_errno.
  */
 static const char *target__error_str[] = {
 	"PID/TID switch overriding CPU",
-	"PID/TID switch overriding UID",
-	"UID switch overriding CPU",
 	"PID/TID switch overriding SYSTEM",
-	"UID switch overriding SYSTEM",
 	"SYSTEM/CPU switch overriding PER-THREAD",
 	"BPF switch overriding CPU",
 	"BPF switch overriding PID/TID",
-	"BPF switch overriding UID",
 	"BPF switch overriding THREAD",
-	"Invalid User: %s",
 };
 
-int target__strerror(struct target *target, int errnum,
+int target__strerror(struct target *target __maybe_unused, int errnum,
 			  char *buf, size_t buflen)
 {
 	int idx;
@@ -173,10 +133,6 @@ int target__strerror(struct target *target, int errnum,
 		snprintf(buf, buflen, "%s", msg);
 		break;
 
-	case TARGET_ERRNO__INVALID_UID:
-		snprintf(buf, buflen, msg, target->uid_str);
-		break;
-
 	default:
 		/* cannot reach here */
 		break;
diff --git a/tools/perf/util/target.h b/tools/perf/util/target.h
index e082bda990fb..84ebb9c940c6 100644
--- a/tools/perf/util/target.h
+++ b/tools/perf/util/target.h
@@ -9,9 +9,7 @@ struct target {
 	const char   *pid;
 	const char   *tid;
 	const char   *cpu_list;
-	const char   *uid_str;
 	const char   *bpf_str;
-	uid_t	     uid;
 	bool	     system_wide;
 	bool	     uses_mmap;
 	bool	     default_per_cpu;
@@ -36,32 +34,24 @@ enum target_errno {
 
 	/* for target__validate() */
 	TARGET_ERRNO__PID_OVERRIDE_CPU	= __TARGET_ERRNO__START,
-	TARGET_ERRNO__PID_OVERRIDE_UID,
-	TARGET_ERRNO__UID_OVERRIDE_CPU,
 	TARGET_ERRNO__PID_OVERRIDE_SYSTEM,
-	TARGET_ERRNO__UID_OVERRIDE_SYSTEM,
 	TARGET_ERRNO__SYSTEM_OVERRIDE_THREAD,
 	TARGET_ERRNO__BPF_OVERRIDE_CPU,
 	TARGET_ERRNO__BPF_OVERRIDE_PID,
-	TARGET_ERRNO__BPF_OVERRIDE_UID,
 	TARGET_ERRNO__BPF_OVERRIDE_THREAD,
 
-	/* for target__parse_uid() */
-	TARGET_ERRNO__INVALID_UID,
-
 	__TARGET_ERRNO__END,
 };
 
 enum target_errno target__validate(struct target *target);
 
 uid_t parse_uid(const char *str);
-enum target_errno target__parse_uid(struct target *target);
 
 int target__strerror(struct target *target, int errnum, char *buf, size_t buflen);
 
 static inline bool target__has_task(struct target *target)
 {
-	return target->tid || target->pid || target->uid_str;
+	return target->tid || target->pid;
 }
 
 static inline bool target__has_cpu(struct target *target)
-- 
2.49.0.604.gff1f9ca942-goog

[PATCH v2 12/12] perf thread_map: Remove uid options

[Ian Rogers]

Now the target doesn't have a uid, it is handled through BPF filters,
remove the uid options to thread_map creation. Tidy up the functions
used in tests to avoid passing unused arguments.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/tests/event-times.c             |  4 +--
 tools/perf/tests/keep-tracking.c           |  2 +-
 tools/perf/tests/mmap-basic.c              |  2 +-
 tools/perf/tests/openat-syscall-all-cpus.c |  2 +-
 tools/perf/tests/openat-syscall.c          |  2 +-
 tools/perf/tests/perf-time-to-tsc.c        |  2 +-
 tools/perf/tests/switch-tracking.c         |  2 +-
 tools/perf/tests/thread-map.c              |  2 +-
 tools/perf/util/evlist.c                   |  2 +-
 tools/perf/util/python.c                   | 10 +++----
 tools/perf/util/thread_map.c               | 32 ++--------------------
 tools/perf/util/thread_map.h               |  6 ++--
 12 files changed, 20 insertions(+), 48 deletions(-)

diff --git a/tools/perf/tests/event-times.c b/tools/perf/tests/event-times.c
index 2148024b4f4a..ae3b98bb42cf 100644
--- a/tools/perf/tests/event-times.c
+++ b/tools/perf/tests/event-times.c
@@ -62,7 +62,7 @@ static int attach__current_disabled(struct evlist *evlist)
 
 	pr_debug("attaching to current thread as disabled\n");
 
-	threads = thread_map__new(-1, getpid(), UINT_MAX);
+	threads = thread_map__new_by_tid(getpid());
 	if (threads == NULL) {
 		pr_debug("thread_map__new\n");
 		return -1;
@@ -88,7 +88,7 @@ static int attach__current_enabled(struct evlist *evlist)
 
 	pr_debug("attaching to current thread as enabled\n");
 
-	threads = thread_map__new(-1, getpid(), UINT_MAX);
+	threads = thread_map__new_by_tid(getpid());
 	if (threads == NULL) {
 		pr_debug("failed to call thread_map__new\n");
 		return -1;
diff --git a/tools/perf/tests/keep-tracking.c b/tools/perf/tests/keep-tracking.c
index 5a3b2bed07f3..eafb49eb0b56 100644
--- a/tools/perf/tests/keep-tracking.c
+++ b/tools/perf/tests/keep-tracking.c
@@ -78,7 +78,7 @@ static int test__keep_tracking(struct test_suite *test __maybe_unused, int subte
 	int found, err = -1;
 	const char *comm;
 
-	threads = thread_map__new(-1, getpid(), UINT_MAX);
+	threads = thread_map__new_by_tid(getpid());
 	CHECK_NOT_NULL__(threads);
 
 	cpus = perf_cpu_map__new_online_cpus();
diff --git a/tools/perf/tests/mmap-basic.c b/tools/perf/tests/mmap-basic.c
index bd2106628b34..04b547c6bdbe 100644
--- a/tools/perf/tests/mmap-basic.c
+++ b/tools/perf/tests/mmap-basic.c
@@ -46,7 +46,7 @@ static int test__basic_mmap(struct test_suite *test __maybe_unused, int subtest
 	char sbuf[STRERR_BUFSIZE];
 	struct mmap *md;
 
-	threads = thread_map__new(-1, getpid(), UINT_MAX);
+	threads = thread_map__new_by_tid(getpid());
 	if (threads == NULL) {
 		pr_debug("thread_map__new\n");
 		return -1;
diff --git a/tools/perf/tests/openat-syscall-all-cpus.c b/tools/perf/tests/openat-syscall-all-cpus.c
index fb114118c876..3644d6f52c07 100644
--- a/tools/perf/tests/openat-syscall-all-cpus.c
+++ b/tools/perf/tests/openat-syscall-all-cpus.c
@@ -28,7 +28,7 @@ static int test__openat_syscall_event_on_all_cpus(struct test_suite *test __mayb
 	struct evsel *evsel;
 	unsigned int nr_openat_calls = 111, i;
 	cpu_set_t cpu_set;
-	struct perf_thread_map *threads = thread_map__new(-1, getpid(), UINT_MAX);
+	struct perf_thread_map *threads = thread_map__new_by_tid(getpid());
 	char sbuf[STRERR_BUFSIZE];
 	char errbuf[BUFSIZ];
 
diff --git a/tools/perf/tests/openat-syscall.c b/tools/perf/tests/openat-syscall.c
index 131b62271bfa..b54cbe5f1808 100644
--- a/tools/perf/tests/openat-syscall.c
+++ b/tools/perf/tests/openat-syscall.c
@@ -20,7 +20,7 @@ static int test__openat_syscall_event(struct test_suite *test __maybe_unused,
 	int err = TEST_FAIL, fd;
 	struct evsel *evsel;
 	unsigned int nr_openat_calls = 111, i;
-	struct perf_thread_map *threads = thread_map__new(-1, getpid(), UINT_MAX);
+	struct perf_thread_map *threads = thread_map__new_by_tid(getpid());
 	char sbuf[STRERR_BUFSIZE];
 	char errbuf[BUFSIZ];
 
diff --git a/tools/perf/tests/perf-time-to-tsc.c b/tools/perf/tests/perf-time-to-tsc.c
index d3e40fa5482c..d4437410c99f 100644
--- a/tools/perf/tests/perf-time-to-tsc.c
+++ b/tools/perf/tests/perf-time-to-tsc.c
@@ -90,7 +90,7 @@ static int test__perf_time_to_tsc(struct test_suite *test __maybe_unused, int su
 	struct mmap *md;
 
 
-	threads = thread_map__new(-1, getpid(), UINT_MAX);
+	threads = thread_map__new_by_tid(getpid());
 	CHECK_NOT_NULL__(threads);
 
 	cpus = perf_cpu_map__new_online_cpus();
diff --git a/tools/perf/tests/switch-tracking.c b/tools/perf/tests/switch-tracking.c
index 8df3f9d9ffd2..96f880c922d1 100644
--- a/tools/perf/tests/switch-tracking.c
+++ b/tools/perf/tests/switch-tracking.c
@@ -351,7 +351,7 @@ static int test__switch_tracking(struct test_suite *test __maybe_unused, int sub
 	const char *comm;
 	int err = -1;
 
-	threads = thread_map__new(-1, getpid(), UINT_MAX);
+	threads = thread_map__new_by_tid(getpid());
 	if (!threads) {
 		pr_debug("thread_map__new failed!\n");
 		goto out_err;
diff --git a/tools/perf/tests/thread-map.c b/tools/perf/tests/thread-map.c
index 1fe521466bf4..54209592168d 100644
--- a/tools/perf/tests/thread-map.c
+++ b/tools/perf/tests/thread-map.c
@@ -115,7 +115,7 @@ static int test__thread_map_remove(struct test_suite *test __maybe_unused, int s
 	TEST_ASSERT_VAL("failed to allocate map string",
 			asprintf(&str, "%d,%d", getpid(), getppid()) >= 0);
 
-	threads = thread_map__new_str(str, NULL, 0, false);
+	threads = thread_map__new_str(str, /*tid=*/NULL, /*all_threads=*/false);
 	free(str);
 
 	TEST_ASSERT_VAL("failed to allocate thread_map",
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 2e1f14bc8461..8a7ec845a611 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -1006,7 +1006,7 @@ int evlist__create_maps(struct evlist *evlist, struct target *target)
 	 * per-thread data. thread_map__new_str will call
 	 * thread_map__new_all_cpus to enumerate all threads.
 	 */
-	threads = thread_map__new_str(target->pid, target->tid, UINT_MAX, all_threads);
+	threads = thread_map__new_str(target->pid, target->tid, all_threads);
 
 	if (!threads)
 		return -1;
diff --git a/tools/perf/util/python.c b/tools/perf/util/python.c
index f3c05da25b4a..56f8ae4cebf7 100644
--- a/tools/perf/util/python.c
+++ b/tools/perf/util/python.c
@@ -566,14 +566,14 @@ struct pyrf_thread_map {
 static int pyrf_thread_map__init(struct pyrf_thread_map *pthreads,
 				 PyObject *args, PyObject *kwargs)
 {
-	static char *kwlist[] = { "pid", "tid", "uid", NULL };
-	int pid = -1, tid = -1, uid = UINT_MAX;
+	static char *kwlist[] = { "pid", "tid", NULL };
+	int pid = -1, tid = -1;
 
-	if (!PyArg_ParseTupleAndKeywords(args, kwargs, "|iii",
-					 kwlist, &pid, &tid, &uid))
+	if (!PyArg_ParseTupleAndKeywords(args, kwargs, "|ii",
+					 kwlist, &pid, &tid))
 		return -1;
 
-	pthreads->threads = thread_map__new(pid, tid, uid);
+	pthreads->threads = thread_map__new(pid, tid);
 	if (pthreads->threads == NULL)
 		return -1;
 	return 0;
diff --git a/tools/perf/util/thread_map.c b/tools/perf/util/thread_map.c
index b5f12390c355..ca193c1374ed 100644
--- a/tools/perf/util/thread_map.c
+++ b/tools/perf/util/thread_map.c
@@ -72,7 +72,7 @@ struct perf_thread_map *thread_map__new_by_tid(pid_t tid)
 	return threads;
 }
 
-static struct perf_thread_map *__thread_map__new_all_cpus(uid_t uid)
+static struct perf_thread_map *thread_map__new_all_cpus(void)
 {
 	DIR *proc;
 	int max_threads = 32, items, i;
@@ -98,15 +98,6 @@ static struct perf_thread_map *__thread_map__new_all_cpus(uid_t uid)
 		if (*end) /* only interested in proper numerical dirents */
 			continue;
 
-		snprintf(path, sizeof(path), "/proc/%s", dirent->d_name);
-
-		if (uid != UINT_MAX) {
-			struct stat st;
-
-			if (stat(path, &st) != 0 || st.st_uid != uid)
-				continue;
-		}
-
 		snprintf(path, sizeof(path), "/proc/%d/task", pid);
 		items = scandir(path, &namelist, filter, NULL);
 		if (items <= 0) {
@@ -157,24 +148,11 @@ static struct perf_thread_map *__thread_map__new_all_cpus(uid_t uid)
 	goto out_closedir;
 }
 
-struct perf_thread_map *thread_map__new_all_cpus(void)
-{
-	return __thread_map__new_all_cpus(UINT_MAX);
-}
-
-struct perf_thread_map *thread_map__new_by_uid(uid_t uid)
-{
-	return __thread_map__new_all_cpus(uid);
-}
-
-struct perf_thread_map *thread_map__new(pid_t pid, pid_t tid, uid_t uid)
+struct perf_thread_map *thread_map__new(pid_t pid, pid_t tid)
 {
 	if (pid != -1)
 		return thread_map__new_by_pid(pid);
 
-	if (tid == -1 && uid != UINT_MAX)
-		return thread_map__new_by_uid(uid);
-
 	return thread_map__new_by_tid(tid);
 }
 
@@ -289,15 +267,11 @@ struct perf_thread_map *thread_map__new_by_tid_str(const char *tid_str)
 	goto out;
 }
 
-struct perf_thread_map *thread_map__new_str(const char *pid, const char *tid,
-				       uid_t uid, bool all_threads)
+struct perf_thread_map *thread_map__new_str(const char *pid, const char *tid, bool all_threads)
 {
 	if (pid)
 		return thread_map__new_by_pid_str(pid);
 
-	if (!tid && uid != UINT_MAX)
-		return thread_map__new_by_uid(uid);
-
 	if (all_threads)
 		return thread_map__new_all_cpus();
 
diff --git a/tools/perf/util/thread_map.h b/tools/perf/util/thread_map.h
index 00ec05fc1656..fc16d87f32fb 100644
--- a/tools/perf/util/thread_map.h
+++ b/tools/perf/util/thread_map.h
@@ -11,13 +11,11 @@ struct perf_record_thread_map;
 struct perf_thread_map *thread_map__new_dummy(void);
 struct perf_thread_map *thread_map__new_by_pid(pid_t pid);
 struct perf_thread_map *thread_map__new_by_tid(pid_t tid);
-struct perf_thread_map *thread_map__new_by_uid(uid_t uid);
-struct perf_thread_map *thread_map__new_all_cpus(void);
-struct perf_thread_map *thread_map__new(pid_t pid, pid_t tid, uid_t uid);
+struct perf_thread_map *thread_map__new(pid_t pid, pid_t tid);
 struct perf_thread_map *thread_map__new_event(struct perf_record_thread_map *event);
 
 struct perf_thread_map *thread_map__new_str(const char *pid,
-		const char *tid, uid_t uid, bool all_threads);
+		const char *tid, bool all_threads);
 
 struct perf_thread_map *thread_map__new_by_tid_str(const char *tid_str);
 
-- 
2.49.0.604.gff1f9ca942-goog

Re: [PATCH v2 00/12] Move uid filtering to BPF filters

[Ian Rogers]

On Thu, Apr 10, 2025 at 10:36 AM Ian Rogers <irogers@google.com> wrote:
>
> Rather than scanning /proc and skipping PIDs based on their UIDs, use
> BPF filters for uid filtering. The /proc scanning in thread_map is
> racy as the PID may exit before the perf_event_open causing perf to
> abort. BPF UID filters are more robust as they avoid the race. Add a
> helper for commands that support UID filtering and wire up. Remove the
> non-BPF UID filtering support given it doesn't work.
>
> v2: Add a perf record uid test (Namhyung) and force setting
>     system-wide for perf trace and perf record (Namhyung). Ensure the
>     uid filter isn't set on tracepoint evsels.
>
> v1: https://lore.kernel.org/lkml/20250111190143.1029906-1-irogers@google.com/

Ping.

Thanks,
Ian

> Ian Rogers (12):
>   perf tests record: Cleanup improvements
>   perf bench evlist-open-close: Reduce scope of 2 variables
>   perf parse-events filter: Use evsel__find_pmu
>   perf target: Separate parse_uid into its own function
>   perf parse-events: Add parse_uid_filter helper
>   perf record: Switch user option to use BPF filter
>   perf tests record: Add basic uid filtering test
>   perf top: Switch user option to use BPF filter
>   perf trace: Switch user option to use BPF filter
>   perf bench evlist-open-close: Switch user option to use BPF filter
>   perf target: Remove uid from target
>   perf thread_map: Remove uid options
>
>  tools/perf/bench/evlist-open-close.c        | 76 ++++++++++++---------
>  tools/perf/builtin-ftrace.c                 |  1 -
>  tools/perf/builtin-kvm.c                    |  2 -
>  tools/perf/builtin-record.c                 | 27 +++++---
>  tools/perf/builtin-stat.c                   |  4 +-
>  tools/perf/builtin-top.c                    | 22 +++---
>  tools/perf/builtin-trace.c                  | 27 +++++---
>  tools/perf/tests/backward-ring-buffer.c     |  1 -
>  tools/perf/tests/event-times.c              |  8 +--
>  tools/perf/tests/keep-tracking.c            |  2 +-
>  tools/perf/tests/mmap-basic.c               |  2 +-
>  tools/perf/tests/openat-syscall-all-cpus.c  |  2 +-
>  tools/perf/tests/openat-syscall-tp-fields.c |  1 -
>  tools/perf/tests/openat-syscall.c           |  2 +-
>  tools/perf/tests/perf-record.c              |  1 -
>  tools/perf/tests/perf-time-to-tsc.c         |  2 +-
>  tools/perf/tests/shell/record.sh            | 36 ++++++++--
>  tools/perf/tests/switch-tracking.c          |  2 +-
>  tools/perf/tests/task-exit.c                |  1 -
>  tools/perf/tests/thread-map.c               |  2 +-
>  tools/perf/util/bpf-filter.c                |  2 +-
>  tools/perf/util/evlist.c                    |  3 +-
>  tools/perf/util/parse-events.c              | 33 ++++++---
>  tools/perf/util/parse-events.h              |  1 +
>  tools/perf/util/python.c                    | 10 +--
>  tools/perf/util/target.c                    | 54 ++-------------
>  tools/perf/util/target.h                    | 15 +---
>  tools/perf/util/thread_map.c                | 32 +--------
>  tools/perf/util/thread_map.h                |  6 +-
>  tools/perf/util/top.c                       |  4 +-
>  tools/perf/util/top.h                       |  1 +
>  31 files changed, 178 insertions(+), 204 deletions(-)
>
> --
> 2.49.0.604.gff1f9ca942-goog
>

Re: [PATCH v2 06/12] perf record: Switch user option to use BPF filter

[Arnaldo Carvalho de Melo]

On Thu, Apr 10, 2025 at 10:36:25AM -0700, Ian Rogers wrote:
> 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. Ensure adding the BPF filter forces
> system-wide.

Since the BPF filter is not introduced in this patch, can you please
provide, in the commit log message or in the patch itself, some
commentary as to how this is accomplished thru a BPF filter?

- Arnaldo
 
> Signed-off-by: Ian Rogers <irogers@google.com>
> ---
>  tools/perf/builtin-record.c | 27 ++++++++++++++++-----------
>  1 file changed, 16 insertions(+), 11 deletions(-)
> 
> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> index ba20bf7c011d..202c917fd122 100644
> --- a/tools/perf/builtin-record.c
> +++ b/tools/perf/builtin-record.c
> @@ -173,6 +173,7 @@ struct record {
>  	bool			timestamp_boundary;
>  	bool			off_cpu;
>  	const char		*filter_action;
> +	const char		*uid_str;
>  	struct switch_output	switch_output;
>  	unsigned long long	samples;
>  	unsigned long		output_max_size;	/* = 0: unlimited */
> @@ -3460,8 +3461,7 @@ static struct option __record_options[] = {
>  		     "or ranges of time to enable events e.g. '-D 10-20,30-40'",
>  		     record__parse_event_enable_time),
>  	OPT_BOOLEAN(0, "kcore", &record.opts.kcore, "copy /proc/kcore"),
> -	OPT_STRING('u', "uid", &record.opts.target.uid_str, "user",
> -		   "user to profile"),
> +	OPT_STRING('u', "uid", &record.uid_str, "user", "user to profile"),
>  
>  	OPT_CALLBACK_NOOPT('b', "branch-any", &record.opts.branch_stack,
>  		     "branch any", "sample any taken branches",
> @@ -4196,19 +4196,24 @@ int cmd_record(int argc, const char **argv)
>  		ui__warning("%s\n", errbuf);
>  	}
>  
> -	err = target__parse_uid(&rec->opts.target);
> -	if (err) {
> -		int saved_errno = errno;
> +	if (rec->uid_str) {
> +		uid_t uid = parse_uid(rec->uid_str);
>  
> -		target__strerror(&rec->opts.target, err, errbuf, BUFSIZ);
> -		ui__error("%s", errbuf);
> +		if (uid == UINT_MAX) {
> +			ui__error("Invalid User: %s", rec->uid_str);
> +			err = -EINVAL;
> +			goto out;
> +		}
> +		err = parse_uid_filter(rec->evlist, uid);
> +		if (err)
> +			goto out;
>  
> -		err = -saved_errno;
> -		goto out;
> +		/* User ID filtering implies system wide. */
> +		rec->opts.target.system_wide = true;
>  	}
>  
> -	/* Enable ignoring missing threads when -u/-p option is defined. */
> -	rec->opts.ignore_missing_thread = rec->opts.target.uid != UINT_MAX || rec->opts.target.pid;
> +	/* Enable ignoring missing threads when -p option is defined. */
> +	rec->opts.ignore_missing_thread = rec->opts.target.pid;
>  
>  	evlist__warn_user_requested_cpus(rec->evlist, rec->opts.target.cpu_list);
>  
> -- 
> 2.49.0.604.gff1f9ca942-goog