From 510e528786395e419e9a827ee5d42add021111ee Mon Sep 17 00:00:00 2001 From: Ian Rogers Date: Tue, 20 Feb 2024 19:41:48 -0800 Subject: perf thread_map: Skip exited threads when scanning /proc 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 Cc: James Clark Cc: Justin Stitt Cc: Bill Wendling Cc: Nick Desaulniers Cc: Yang Jihong Cc: Nathan Chancellor Cc: Kan Liang Cc: Athira Jajeev Cc: llvm@lists.linux.dev Signed-off-by: Namhyung Kim Link: https://lore.kernel.org/r/20240221034155.1500118-2-irogers@google.com --- tools/perf/util/thread_map.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) (limited to 'tools') diff --git a/tools/perf/util/thread_map.c b/tools/perf/util/thread_map.c index ea3b431b9783..b5f12390c355 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 @@ out_free_namelist: for (i = 0; i < items; i++) zfree(&namelist[i]); free(namelist); - -out_free_closedir: zfree(&threads); goto out_closedir; } -- cgit v1.2.3