Commit e2c18168 authored by Arnaldo Carvalho de Melo's avatar Arnaldo Carvalho de Melo
Browse files

libperf: Remove BUG_ON() from library code in get_group_fd() 



We shouldn't just panic, return a value that doesn't clash with what
perf_evsel__open() was already returning in case of error, i.e. errno
when sys_perf_event_open() fails.

Acked-by: default avatarJiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Shunsuke Nakamura <nakamura.shun@fujitsu.com>
Link: http://lore.kernel.org/lkml/YOiOA5zOtVH9IBbE@kernel.org


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 3fd35de1

tools/lib/perf/evsel.c

+16 −7
Original line number Diff line number Diff line
@@ -77,23 +77,30 @@ sys_perf_event_open(struct perf_event_attr *attr, 
	return syscall(__NR_perf_event_open, attr, pid, cpu, group_fd, flags);

}



static int get_group_fd(struct perf_evsel *evsel, int cpu, int thread)

static int get_group_fd(struct perf_evsel *evsel, int cpu, int thread, int *group_fd)

{

	struct perf_evsel *leader = evsel->leader;

	int fd;



	if (evsel == leader)

		return -1;

	if (evsel == leader) {

		*group_fd = -1;

		return 0;

	}



	/*

	 * Leader must be already processed/open,

	 * if not it's a bug.

	 */

	BUG_ON(!leader->fd);

	if (!leader->fd)

		return -ENOTCONN;



	fd = FD(leader, cpu, thread);

	BUG_ON(fd == -1);

	return fd;

	if (fd == -1)

		return -EBADF;



	*group_fd = fd;



	return 0;

}



int perf_evsel__open(struct perf_evsel *evsel, struct perf_cpu_map *cpus,
@@ -133,7 +140,9 @@ int perf_evsel__open(struct perf_evsel *evsel, struct perf_cpu_map *cpus, 
		for (thread = 0; thread < threads->nr; thread++) {

			int fd, group_fd;



			group_fd = get_group_fd(evsel, cpu, thread);

			err = get_group_fd(evsel, cpu, thread, &group_fd);

			if (err < 0)

				return err;



			fd = sys_perf_event_open(&evsel->attr,

						 threads->map[thread].pid,