diff mbox series

[v1,1/9] perf thread_map: Skip exited threads when scanning /proc

Message ID 20231201235031.475293-1-irogers@google.com
State New
Headers
Series [v1,1/9] perf thread_map: Skip exited threads when scanning /proc |

Commit Message

Ian Rogers Dec. 1, 2023, 11:50 p.m. UTC 
  Scanning /proc is inherently racy. Scanning /proc/pid/task within that
is also racy as the pid can terminate. Rather than failing in
__thread_map__new_all_cpus, skip pids for such failures.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/util/thread_map.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)
diff mbox series

Patch

diff --git a/tools/perf/util/thread_map.c b/tools/perf/util/thread_map.c
index e848579e61a8..18fbc41d09f3 100644
--- a/tools/perf/util/thread_map.c
+++ b/tools/perf/util/thread_map.c
@@ -109,9 +109,10 @@  static struct perf_thread_map *__thread_map__new_all_cpus(uid_t uid)
 
 		snprintf(path, sizeof(path), "/proc/%d/task", pid);
 		items = scandir(path, &namelist, filter, NULL);
-		if (items <= 0)
-			goto out_free_closedir;
-
+		if (items <= 0) {
+			pr_debug("scandir for %d returned empty, skipping\n", pid);
+			continue;
+		}
 		while (threads->nr + items >= max_threads) {
 			max_threads *= 2;
 			grow = true;
@@ -152,8 +153,6 @@  static struct perf_thread_map *__thread_map__new_all_cpus(uid_t uid)
 	for (i = 0; i < items; i++)
 		zfree(&namelist[i]);
 	free(namelist);
-
-out_free_closedir:
 	zfree(&threads);
 	goto out_closedir;
 }