Commit 2c369d91 authored by Ian Rogers's avatar Ian Rogers Committed by Namhyung Kim
Browse files

perf symbol: Add blocking argument to filename__read_build_id 



When synthesizing build-ids, for build ID mmap2 events, they will be
added for data mmaps if -d/--data is specified. The files opened for
their build IDs may block on the open causing perf to hang during
synthesis. There is some robustness in existing calls to
filename__read_build_id by checking the file path is to a regular
file, which unfortunately fails for symlinks. Rather than adding more
is_regular_file calls, switch filename__read_build_id to take a
"block" argument and specify O_NONBLOCK when this is false. The
existing is_regular_file checking callers and the event synthesis
callers are made to pass false and thereby avoiding the hang.

Fixes: 53b00ff3 ("perf record: Make --buildid-mmap the default")
Signed-off-by: default avatarIan Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250823000024.724394-3-irogers@google.com


Signed-off-by: default avatarNamhyung Kim <namhyung@kernel.org>
parent ba0b7081

tools/perf/bench/inject-buildid.c

+1 −1
Original line number Diff line number Diff line
@@ -85,7 +85,7 @@ static int add_dso(const char *fpath, const struct stat *sb __maybe_unused, 
	if (typeflag == FTW_D || typeflag == FTW_SL)

		return 0;



	if (filename__read_build_id(fpath, &bid) < 0)

	if (filename__read_build_id(fpath, &bid, /*block=*/true) < 0)

		return 0;



	dso->name = realpath(fpath, NULL);

tools/perf/builtin-buildid-cache.c

+4 −4
Original line number Diff line number Diff line
@@ -180,7 +180,7 @@ static int build_id_cache__add_file(const char *filename, struct nsinfo *nsi) 
	struct nscookie nsc;



	nsinfo__mountns_enter(nsi, &nsc);

	err = filename__read_build_id(filename, &bid);

	err = filename__read_build_id(filename, &bid, /*block=*/true);

	nsinfo__mountns_exit(&nsc);

	if (err < 0) {

		pr_debug("Couldn't read a build-id in %s\n", filename);
@@ -204,7 +204,7 @@ static int build_id_cache__remove_file(const char *filename, struct nsinfo *nsi) 
	int err;



	nsinfo__mountns_enter(nsi, &nsc);

	err = filename__read_build_id(filename, &bid);

	err = filename__read_build_id(filename, &bid, /*block=*/true);

	nsinfo__mountns_exit(&nsc);

	if (err < 0) {

		pr_debug("Couldn't read a build-id in %s\n", filename);
@@ -280,7 +280,7 @@ static bool dso__missing_buildid_cache(struct dso *dso, int parm __maybe_unused) 
	if (!dso__build_id_filename(dso, filename, sizeof(filename), false))

		return true;



	if (filename__read_build_id(filename, &bid) == -1) {

	if (filename__read_build_id(filename, &bid, /*block=*/true) == -1) {

		if (errno == ENOENT)

			return false;
@@ -309,7 +309,7 @@ static int build_id_cache__update_file(const char *filename, struct nsinfo *nsi) 
	int err;



	nsinfo__mountns_enter(nsi, &nsc);

	err = filename__read_build_id(filename, &bid);

	err = filename__read_build_id(filename, &bid, /*block=*/true);

	nsinfo__mountns_exit(&nsc);

	if (err < 0) {

		pr_debug("Couldn't read a build-id in %s\n", filename);

tools/perf/builtin-inject.c

+2 −2
Original line number Diff line number Diff line
@@ -680,12 +680,12 @@ static int dso__read_build_id(struct dso *dso) 


	mutex_lock(dso__lock(dso));

	nsinfo__mountns_enter(dso__nsinfo(dso), &nsc);

	if (filename__read_build_id(dso__long_name(dso), &bid) > 0)

	if (filename__read_build_id(dso__long_name(dso), &bid, /*block=*/true) > 0)

		dso__set_build_id(dso, &bid);

	else if (dso__nsinfo(dso)) {

		char *new_name = dso__filename_with_chroot(dso, dso__long_name(dso));



		if (new_name && filename__read_build_id(new_name, &bid) > 0)

		if (new_name && filename__read_build_id(new_name, &bid, /*block=*/true) > 0)

			dso__set_build_id(dso, &bid);

		free(new_name);

	}

tools/perf/tests/sdt.c

+1 −1
Original line number Diff line number Diff line
@@ -31,7 +31,7 @@ static int build_id_cache__add_file(const char *filename) 
	struct build_id bid = { .size = 0, };

	int err;



	err = filename__read_build_id(filename, &bid);

	err = filename__read_build_id(filename, &bid, /*block=*/true);

	if (err < 0) {

		pr_debug("Failed to read build id of %s\n", filename);

		return err;

tools/perf/util/build-id.c

+2 −2
Original line number Diff line number Diff line
@@ -115,7 +115,7 @@ int filename__snprintf_build_id(const char *pathname, char *sbuild_id, size_t sb 
	struct build_id bid = { .size = 0, };

	int ret;



	ret = filename__read_build_id(pathname, &bid);

	ret = filename__read_build_id(pathname, &bid, /*block=*/true);

	if (ret < 0)

		return ret;
@@ -841,7 +841,7 @@ static int filename__read_build_id_ns(const char *filename, 
	int ret;



	nsinfo__mountns_enter(nsi, &nsc);

	ret = filename__read_build_id(filename, bid);

	ret = filename__read_build_id(filename, bid, /*block=*/true);

	nsinfo__mountns_exit(&nsc);



	return ret;