From nobody Thu Sep 19 02:14:05 2024 Received: from mail-yw1-f202.google.com (mail-yw1-f202.google.com [209.85.128.202]) (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 BB6ED38DE6 for ; Wed, 21 Feb 2024 03:42:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.202 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708486927; cv=none; b=eCv+nGSQBmQYOk6Na9xrPmffHZJ4SO9/Qo3b2dcdx3se+bRv7yg7gchcvu4PF3zK8TLG3SlB7ydi5AnPMWIZA7zhCFJ1korA3o7A2hylsjQal9C69/7hVqWHMmtoP+r6ldsvvQ4rnDz6t5pntLybOduqiR4VotioTtuACgULSfM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708486927; c=relaxed/simple; bh=o/osGCI+hvlD14sD3OCM5ESdLYEEWx1V7jgoXENiCKc=; h=Date:In-Reply-To:Message-Id:Mime-Version:References:Subject:From: To:Content-Type; b=bZ9mz9mnXPRTFPibPRgfUKv6IlyzWnFf29chPDpm7EF3IOO6BDuZJlC9AeTslrevU2RiDRoNqg1Lv/PMkzjsqMyCNPr22lCVyBV/ilTEckBdRt4weoydtQ7+sT29JTAuf0hMmVSzXkbvVU9hHlPe33ImFXpkM00AOafUb3cHyuI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--irogers.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=bvs0jjKY; arc=none smtp.client-ip=209.85.128.202 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="bvs0jjKY" Received: by mail-yw1-f202.google.com with SMTP id 00721157ae682-607cd6c11d7so89979957b3.0 for ; Tue, 20 Feb 2024 19:42:05 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1708486925; x=1709091725; darn=vger.kernel.org; h=to:from:subject:references:mime-version:message-id:in-reply-to:date :from:to:cc:subject:date:message-id:reply-to; bh=uv/9NgKdLz0z52mqtvy0vTSbbBgaPJcb0Vk69+L979Q=; b=bvs0jjKYG21ZkB+YgfE5BE740UXuO77Aq3aGQVuxlIvR4Api1Wd4UkAzo8tzSYpyxu qgIcKEqtQo9kzYmWGUOYEzQqHm3T419K97jcCG6JD54rA6kt9TW3725qnQ91FWLCSKld DkO2R3m1FoX6F5W9P+Lz18oSTagIl5/cO6lUWg1G7Uw/eXm39MRhHadPE9CjR24Tt3FS w8g6c+vm1zP/XJcMZJ9rTkmPOW5IHsHgB9NA5KU0rMlj3wY9F4rKgehtcnq40to/jKhT GaZmDyaiksQFqofW5FfXSwirlu2KlyFgPt0WQcQmCX1WZ6nZR/aWrE31NPuKo38UqC21 W9Og== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1708486925; x=1709091725; h=to:from:subject:references:mime-version:message-id:in-reply-to:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=uv/9NgKdLz0z52mqtvy0vTSbbBgaPJcb0Vk69+L979Q=; b=FiSE3G/wbQeeZHE2Yyxj96B+pbzEA9YdCXNDZhjv1mXCpy13cdQ+ooVhKlLHC5zIXO SREMRVAR78iWfzQOuPAfflkbbILjJi/MtKvLVo5xHQo+E9CRUmbnx0cpD8JeIiwsuOi7 jIPh8byUHMVhkVxlt7aEPY/uiTYWkphKYDbh/lYQR+jVcoUHu4ja9UaHox6zmpIPUF9a 1RHoujmP1XC0xuU0DBLZs2MHQo+jPfUJQAKUNuDk9agDRWeW3Z/Tz48BWwsbMHunsoki yrxPlxZLGSwzCsNoLTtSSyHnuzsV848hL2AwN4W9pgL3DUh4uB1Cwm0bn18hjsUg51rj Y9AQ== X-Forwarded-Encrypted: i=1; AJvYcCUtQxHnKdxUa5ft6FxY0TE8f9c4FkSX46hJ51HrvpG/g+zKh6acWPeYzBiKCh7sXjdsPEPwvnW+wlpQN+hox5QWocmgjiN7SqDDX5je X-Gm-Message-State: AOJu0YxhNijls3m6aAbKPZQEQVBVT9XXSF9NUyo1+qN5F13VgRpvZkcZ LCwJX1iAZjqBZgmW1gfSif08HEPEsi1PL1Z5eWYuDdIg1P1hgLaEA0RzWUqvUrJ7FXw4kqWshkB BtBnN+Q== X-Google-Smtp-Source: AGHT+IGqHOfbFeUMm04fgBII6BGPdq0HLJ7wcSG61rdgw+C9Xjypqm77xVwuEi9AZKTTTzR7Hwymw6gQ+OLN X-Received: from irogers.svl.corp.google.com ([2620:15c:2a3:200:3c02:f882:5876:b7ab]) (user=irogers job=sendgmr) by 2002:a25:db93:0:b0:dc7:9218:df3b with SMTP id g141-20020a25db93000000b00dc79218df3bmr708882ybf.10.1708486924814; Tue, 20 Feb 2024 19:42:04 -0800 (PST) Date: Tue, 20 Feb 2024 19:41:48 -0800 In-Reply-To: <20240221034155.1500118-1-irogers@google.com> Message-Id: <20240221034155.1500118-2-irogers@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240221034155.1500118-1-irogers@google.com> X-Mailer: git-send-email 2.44.0.rc0.258.g7320e95886-goog Subject: [PATCH v6 1/8] perf thread_map: Skip exited threads when scanning /proc From: Ian Rogers To: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Mark Rutland , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , Nathan Chancellor , Nick Desaulniers , Bill Wendling , Justin Stitt , Athira Jajeev , James Clark , Kan Liang , Yang Jihong , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, llvm@lists.linux.dev Content-Transfer-Encoding: quoted-printable 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 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_c= pus(uid_t uid) =20 snprintf(path, sizeof(path), "/proc/%d/task", pid); items =3D scandir(path, &namelist, filter, NULL); - if (items <=3D 0) - goto out_free_closedir; - + if (items <=3D 0) { + pr_debug("scandir for %d returned empty, skipping\n", pid); + continue; + } while (threads->nr + items >=3D max_threads) { max_threads *=3D 2; grow =3D true; @@ -152,8 +153,6 @@ static struct perf_thread_map *__thread_map__new_all_cp= us(uid_t uid) for (i =3D 0; i < items; i++) zfree(&namelist[i]); free(namelist); - -out_free_closedir: zfree(&threads); goto out_closedir; } --=20 2.44.0.rc0.258.g7320e95886-goog