From nobody Fri Oct 18 08:37:18 2024 Received: from mail-yb1-f202.google.com (mail-yb1-f202.google.com [209.85.219.202]) (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 A96624596E for ; Mon, 12 Feb 2024 18:59:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.219.202 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707764352; cv=none; b=NOx5yXPbZmEmVEIAz20dffNTgxiDMM23PkEDi6C2WNnRw6CezSBWMnQ2xfCzuOiFOxX8ZTMDCwLM04X7iy+tY/mpaJ41GxPdL1kCL2VEBgPOeGoRSJn7saBEgDQIZMy1WiXsSZYMKfeydGPdv3WfNy29qkfcpEihI7HU1E1czp8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707764352; c=relaxed/simple; bh=9GvaQ8U/ciyGf0POxeefEusSW20t+DHMSsugj/N6ETY=; h=Date:In-Reply-To:Message-Id:Mime-Version:References:Subject:From: To:Content-Type; b=p9Xyycqz5OAzMP5x6AH9UXmDPib0it4ITP/p7IFBYBsdCSJo0wjWIu81r1avH+G3omxzL0ia4/VxTDZkEut3ZUsKuIB/oj2AGX650A6bbtKDmXTnTWqaJ0fid943lVfwbMkjC4oDP0TaQurvQ7Hm9o0rnVYgIcyUn3MZga/X5UM= 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=pma60R5z; arc=none smtp.client-ip=209.85.219.202 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="pma60R5z" Received: by mail-yb1-f202.google.com with SMTP id 3f1490d57ef6-dc74645bfa8so126788276.1 for ; Mon, 12 Feb 2024 10:59:10 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1707764349; x=1708369149; 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=F6UUwQ6uU0gh1AgBT5LAdlyWuLVQW/eRWP9wNVATd0w=; b=pma60R5zHeE04LRBeGIwCBhS8j+w+e2dINMD07Tw+sO5K5oDGkV3vTBu/jkDZmkF99 qwEVMpLxFthmRUMx5AxSQ8NEQ37PW5Irh1yLy8fLO2a2FKJKwL21V9PbXDDjLR/ieVfG JvxHiZHuxiWB8pXKIXI3cGDaorGndfGbxoODxJC4t2fMgrdw37Es6Yb8qRxf9Wp1Ob12 V5u0JG34Vf0PD5T73GviB9uZJLoFPmHh0nrkatnb7YrH6bysD6XKOxKAaCprEwDUS1Eq cTxkjM3E5s980bQ2KqFN5FXhuetSNbnh7EArJVqfsSEgQBRFwRwwYrIw2K1ebfZlMV53 DRzA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1707764349; x=1708369149; 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=F6UUwQ6uU0gh1AgBT5LAdlyWuLVQW/eRWP9wNVATd0w=; b=ci7Abvej/wqf8tAeISXzj7mLKp5jVFGb5Pm8hT/tVp3wS/aU+eRN8ZFkJp8eqUv3/E kBk36CtRQYUcqa/3Ews3zUfb10+cR/5Iv5R/VnqbtyuhYqx7MdAWO9OWVI1D059xm17u jcvBDR4FbTHAUDgUzzeL0M38zM1TRMMaYopvJzAMJ5su418OdhoDneLAe8EA6XqnoxbC 7zawCsEI7tm9tUCTwxKAu9ILLLxUtSBzLo7Ts9dA6xIjvCeEk/LYaJk8mauqL1lM3nTY d9pz3VVyelmSwVoxv2sDo8dcbpuUa28q9W3ZnD+JWl691fNqBePSZ+snHC5jz58vPLtk slwg== X-Forwarded-Encrypted: i=1; AJvYcCUU8d8BZZc1glFfNspCYJVnRmkRxSlxPZhWP0j8uvqQxFoJtsWwjuCHsz3U6jxjdVFc7v6qcsGu7+oSZUPLXmqK7t81+Q207CJ7YNT4 X-Gm-Message-State: AOJu0YyXvicO59MrU6AZsSS1U43C9frMWSXEFrl0Ss7cnhGrYu2abi8h tyYCp5amLoFjuEKv1HkEV1AuQB1sQ2b2Cd7EAVEN3LjJFEKqDQLsONv3vvxdIyG5tCDWf/+5F19 2LSPySQ== X-Google-Smtp-Source: AGHT+IHSN4ECweWB1sjgp7X1buxa09RypuopSmFNaefe0SEaS78M3SDkr3wLQ4m5gAc4tVA7kyQuIFcZ7NsM X-Received: from irogers.svl.corp.google.com ([2620:15c:2a3:200:125c:bcda:4fe2:b6e6]) (user=irogers job=sendgmr) by 2002:a25:aa2a:0:b0:dcc:41ad:fb3b with SMTP id s39-20020a25aa2a000000b00dcc41adfb3bmr6327ybi.10.1707764349685; Mon, 12 Feb 2024 10:59:09 -0800 (PST) Date: Mon, 12 Feb 2024 10:58:51 -0800 In-Reply-To: <20240212185858.68189-1-irogers@google.com> Message-Id: <20240212185858.68189-2-irogers@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240212185858.68189-1-irogers@google.com> X-Mailer: git-send-email 2.43.0.687.g38aa6559b0-goog Subject: [PATCH v3 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 , James Clark , Athira Jajeev , 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 2.43.0.687.g38aa6559b0-goog