From mboxrd@z Thu Jan 1 00:00:00 1970 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 D6447C14F for ; Wed, 14 Feb 2024 04:54:34 +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=1707886476; cv=none; b=bhZlyX2abcRroBoFpIkHb3iYz7+UD+INEumiUP0aIsaNviK/Qr8VS/9Jj8xNQPFakl9Pnj2Yzp1qU3bsjTZmoMxXvlLuoNrrli0/iy6ZjuDetvZaGMFuvjB4JRKqMtqGdQFqk5jR6YJYmi9uRI56ZCrHXAJkW21+GiRx4rIJ644= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707886476; c=relaxed/simple; bh=9GvaQ8U/ciyGf0POxeefEusSW20t+DHMSsugj/N6ETY=; h=Date:In-Reply-To:Message-Id:Mime-Version:References:Subject:From: To:Content-Type; b=KXd0EB6GbFEiBbX/ZcW3RVpfO8sBARiA/4vB7pD0PqmW32R2ecgqqn2XK5HXQz5sUkZ/1Ct2pK4ypd6YtSMuqsuFGn2SQ5Xpvgwzo4qT6vypE6uLEhaOEpvSKp2PvP6vAL3pY0M9bccWlsLlvaZ7grMjodTa3EH/cG5C5e7tYr0= 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=xUNo3MuT; 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="xUNo3MuT" Received: by mail-yb1-f202.google.com with SMTP id 3f1490d57ef6-dbf618042daso2820868276.0 for ; Tue, 13 Feb 2024 20:54:34 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1707886474; x=1708491274; 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=xUNo3MuTCHNPNBQSi0iOeCYRhkZNpLcWuhCz+RXhzVfhzxK+TFj5UCTqB1yjMiEgf4 Y2IG/TsNqIuLvuXhVgwCfrFqkulqkxzpGVoKkvlnkvgmtXb2fvm49DMi+Cx4GsUWHQrZ sWYmkj0jSbpPEK9d36KD+H81PqEqLB+Dy2jKJeYw3fZYvAS1ASJvzI4cLcAKXNtG/yUE TWjImoL4OLfJtmjCA1uNDwXgoX/RJOZzGnIhuSWn0e/QVWX2zxnobM7lxur5JaxWHXVI Q5X5Zf41wd99vLJfhXQ4rztXfxNuf+epH4qJaFXBRbgLreCLKQGyL2o/vWpZP1VeA/E9 3aAw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1707886474; x=1708491274; 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=HCVIO5eJFrWYSw63U99B/hVZjvEh1ImfFd2yqYJwvzDHmtgusuwnobNEwleGqEXIkq U1TKjo4B5mRO7tyckc3QrxuFV5h0O1giDAbcrkJMOM/gFluHGGidogfLcTW2lm453udo 29oqqVirV0TiWcx7SbcbEaVtPGcbmEZwMG6WLi41VT/cQs4rSl+9vUzPI2dOaaGKuHTf D0Z+cUzkKLrtYpxzKfHaZ60/WswjdTsJnycmcGMWx2bp9KbcQuKwwsRrjhMw4VqTNvvH Q2PrMhtBsDF3KQhw0UQuoxyIklM1aEfb6L7wZeJQCmNULtgN/o4tdGyiDkGlrVFuEQ4r 1Lew== X-Forwarded-Encrypted: i=1; AJvYcCWtsp4rRPE3N+5uehvrzSNEEDTYvPDphe+Q97+3WC/XiQbhzoLyLwYYZbDkj5ojWTABfaXgV7RbgFD6NMr6+KwQGvou2Xx8I3MucGhTEtmcUg== X-Gm-Message-State: AOJu0Yyt6AYTGw44TkYPARR2c8TXxBh+O6wrlZE1EJikoIdiS/67vDKn tgvdjD4JHJXqPl0A7dPFLTq4zpn7RpOlcWUgMoygNtAm0fZDHNZ6a2ITLYZ0WhGNmrEVKGMR3fY a5GOJQw== X-Google-Smtp-Source: AGHT+IEYhgWjbXFx0sxYnQQnVr7GNh7ZLD+INkja+l1mji2uo3Azkx4WVasjvNd44POf3VLkrK39N5w37xYF X-Received: from irogers.svl.corp.google.com ([2620:15c:2a3:200:6d92:85eb:9adc:66dd]) (user=irogers job=sendgmr) by 2002:a25:d3c6:0:b0:dc7:6cfa:dc59 with SMTP id e189-20020a25d3c6000000b00dc76cfadc59mr50124ybf.4.1707886473857; Tue, 13 Feb 2024 20:54:33 -0800 (PST) Date: Tue, 13 Feb 2024 20:53:49 -0800 In-Reply-To: <20240214045356.748330-1-irogers@google.com> Message-Id: <20240214045356.748330-2-irogers@google.com> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240214045356.748330-1-irogers@google.com> X-Mailer: git-send-email 2.43.0.687.g38aa6559b0-goog Subject: [PATCH v4 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-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_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; } -- 2.43.0.687.g38aa6559b0-goog