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

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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: Jiri 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: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Arnaldo Carvalho de Melo 2021-07-09 14:52:16 -03:00
parent 3fd35de168
commit e2c18168c3
1 changed files with 16 additions and 7 deletions
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23
tools/lib/perf/evsel.c
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@ -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,