From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-yb1-f201.google.com (mail-yb1-f201.google.com [209.85.219.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7F941619D2 for ; Fri, 1 Dec 2023 23:50:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--irogers.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="re9JmNZX" Received: by mail-yb1-f201.google.com with SMTP id 3f1490d57ef6-db7d201be93so872007276.2 for ; Fri, 01 Dec 2023 15:50:40 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1701474639; x=1702079439; darn=lists.linux.dev; h=to:from:subject:mime-version:message-id:date:from:to:cc:subject :date:message-id:reply-to; bh=PMWeTAylF3bUIvrApUeKD5Af/l0nzPxNAdOfQ8ZWtyk=; b=re9JmNZXkr8o/aNGSRX72XSo6oMbAvP2VwLNFW6gGwiDRVJVLBpFLbd4ia5qUB9SwO kefIszXCkVGFltSoZbkmdKXhefjr9BWWULgGSEQLKeJwGWNhOtecQ1z7m2palVOZQQsD HXbQ1QvUyV4DA+Ff7kJcaV2QbtIjbcroilfHgfWsGNI65LtSHOa1mnELMUDXeeVO0BsD h8vXLFP0OmJ+WXT4AxckxzodIv17Rt3rZFgK1tg5bj8QsqmOhvkAFrlNpCpJgUNQlvPR 28jnNPKAQUD6BlxZqC+U8IXtFuEzlJsuU5TKShesZMC2FI6/U3HPYyuh37nzXS6ifkx4 Ue1A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1701474639; x=1702079439; h=to:from:subject:mime-version:message-id:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=PMWeTAylF3bUIvrApUeKD5Af/l0nzPxNAdOfQ8ZWtyk=; b=lXqbLFVTm6Mc8b6uWiMbglujs0iR6UH7/kz4Cq+lJM0/n9t2AmxuN/9kzSsQA7/bvi n7WAzNSozU5DYvuVfHMyvEoaNCHAfuXz0NLvaG6kdoM7m6BJ9+dmgyHxNh5/uIv+VKu2 GTAgOl3shNDFdYsCZOSEuVQVMtnLEtZu/7o8R1e2bqGUmbabrl0Hw37p3Srblq1UwSa8 ToFI5cucrRI0sQhd98MeCxWMv5fIpRRpR73k5hl8hODxe/BZvDdOB2xH6+gzIzAbmxcq 176hG5wG5E4BqKcSYMWffpWoSvtg4o1DlhtXCVyhiOF5DjNsbwvnEpzNHXD1bj9ubtTK yw2w== X-Gm-Message-State: AOJu0YyO3dnHg5w8v0DR5MUf9o58vQGDATITRcs66nHgUKitmFjEFXAR /c/ulmH/eQPgFSdAVtL9B3MVGhPuhccK X-Google-Smtp-Source: AGHT+IFNARd7MyKjCR2gLvJy45/OB20UrZiZukoWo3tgtMA/0nbQdgyhR+LI1WVbM0lMkdiPHvakkjNz/pMc X-Received: from irogers.svl.corp.google.com ([2620:15c:2a3:200:df3:224b:7b7f:efc5]) (user=irogers job=sendgmr) by 2002:a25:dad3:0:b0:db5:3d61:8e63 with SMTP id n202-20020a25dad3000000b00db53d618e63mr241281ybf.13.1701474639430; Fri, 01 Dec 2023 15:50:39 -0800 (PST) Date: Fri, 1 Dec 2023 15:50:23 -0800 Message-Id: <20231201235031.475293-1-irogers@google.com> Precedence: bulk X-Mailing-List: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-Mailer: git-send-email 2.43.0.rc2.451.g8631bc7472-goog Subject: [PATCH v1 1/9] perf thread_map: Skip exited threads when scanning /proc From: Ian Rogers To: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Ian Rogers , Adrian Hunter , Nathan Chancellor , Nick Desaulniers , Tom Rix , Ravi Bangoria , James Clark , Kan Liang , John Garry , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, llvm@lists.linux.dev Content-Type: text/plain; charset="UTF-8" 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 --- tools/perf/util/thread_map.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) 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; } -- 2.43.0.rc2.451.g8631bc7472-goog