From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 208C0C07E97 for ; Fri, 1 Dec 2023 23:50:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232109AbjLAXui (ORCPT ); Fri, 1 Dec 2023 18:50:38 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50574 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229447AbjLAXuf (ORCPT ); Fri, 1 Dec 2023 18:50:35 -0500 Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3AC9310E4 for ; Fri, 1 Dec 2023 15:50:40 -0800 (PST) Received: by mail-yb1-xb4a.google.com with SMTP id 3f1490d57ef6-db548f8dae4so1467234276.3 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=vger.kernel.org; h=to:from:subject:mime-version:message-id:date:from:to:cc:subject :date:message-id:reply-to; bh=PMWeTAylF3bUIvrApUeKD5Af/l0nzPxNAdOfQ8ZWtyk=; b=VPLK8ylzIs3LTjCvGHt2TOWKY6j5qZOCmv4K5x+D3BP3VeNe+ETocBZMJnW7kS1yll y+6h7yhVC1i4z8uHnSxkQNaSkXqru//4CzP2MMDfiP7wCnFg8otITcuVT+FsoH6jUj3d 2gcrgTVmlUXzYHWf5KFMzj+DORb8qHSNcYBy6xcZdZp/7kfU21r4N1pq8+R/J6W652Hf zbo4AEPvP6rgUEZzykB2T/fbB9zIoKZOlLhboNw9n4Sha4rfs3pF0GOB96zqh3W4E4wH 6RGZiXbOrUjKStkr4D/xw4udz48v5T2eyiN0+elVTmofHlCMLVP/Nz2LiLJy6lh32u4/ AsFA== 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=ofNVr5kglKDFkUVHbitCCqC8X/muTL/xEVlUwQefZEHlDDvlknq2Ro58mSaLvL23bd yD3VA/6gc9EgMjxJQHRPJBmay6vUXx7tjtpF9NrrUBrMqku+fRLA70eCePBxTb4zWOWl YKEnmU4n9QHpbjujO0CXGxGA8eDsvUmFzcuW2mBLyjKOUZZVSEhSND0g43UUG5A7zWX5 /sAwzsqLrgaiLCAybqS5RvzRBzkVAI8/KRvv1bWZezRt4kvxagDB+Q3CjgI2oyKBX95v o/RBJfhj/O+Ye0Y9dj+HJrWBH5pmHoILXRNSwarsPkS47W08498gIXSTCjKOs3rQUn/Z SQ7Q== X-Gm-Message-State: AOJu0YxFqsvKJsYgInnmY1cqxQ/dfsc9UtuwAD825XtB/AUHgsLMaUVR 8X0bTU3QuesBL/LaLwhnY3twlavjLI+t 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> 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" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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