From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS31976 209.132.180.0/23 X-Spam-Status: No, score=-2.5 required=3.0 tests=AWL,BAYES_00, DKIM_ADSP_CUSTOM_MED,DKIM_SIGNED,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_HI,RCVD_IN_SORBS_SPAM, RP_MATCHES_RCVD,T_DKIM_INVALID shortcircuit=no autolearn=no autolearn_force=no version=3.4.0 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by dcvr.yhbt.net (Postfix) with ESMTP id 09BB4208CD for ; Mon, 21 Aug 2017 17:44:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754124AbdHURoM (ORCPT ); Mon, 21 Aug 2017 13:44:12 -0400 Received: from mail-wr0-f195.google.com ([209.85.128.195]:37025 "EHLO mail-wr0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754072AbdHURoK (ORCPT ); Mon, 21 Aug 2017 13:44:10 -0400 Received: by mail-wr0-f195.google.com with SMTP id z91so19038386wrc.4 for ; Mon, 21 Aug 2017 10:44:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=wte96Em+LgCDcuaDtCwj3k8Mcaec1GlxI6Ay8w25L3M=; b=j08y68U+L7emvnbFLKMVX+UMH3TCXh0nuh90G8BDfvMmyTehsU8RKQsRywFOSTCy5M 74LSRxcLUzGy3/oSQJFlXb55Jum9NeCSruuXMLXJWMUZRIBXgdPn10m6QNmgNAI8/sSq LcU46iHtxIkUCEghs0MFMfQUyC4baqH2OV9GnukXBmzlQcmvEfBsFeDYN0vMueV3vRXM 4I4HA8pz9q5rT1c2QOmAxsJJr0eX6SKQMTQVuDWmlOE+YQ9vr5PEPib5Sh09gcTa6/+3 a/F9CgC5FYG/pxzLquPXLpjGtTQD0N1Enzx+ZUluTuGkH9iSAoe/Ljq1dsKfS3sQ/EQ5 RuCQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=wte96Em+LgCDcuaDtCwj3k8Mcaec1GlxI6Ay8w25L3M=; b=FsT4bFWk9/OnqZk99d8pQLE0KbhgxMFa6aW2do0i0gfQDzoZFYA0lgEQ0yNGU5JPt3 cBrpSopQFE5gspRTgz4TGMqIFUQGA4NgePZWBswspDua7qse9ZjoY7K2p4uLhHhkIRR3 SoIp6I1S2m9b+pC1mRGq/ydvVedYOgpE/+12ypw1tS4cBrdgoIsU93TTRWOuOGg5E/DN vbj+LdLvS9UXrrah3DhdkASb1Hlo32OpeqUNO0mF70utodknR9jU0AEv+hJvPo7aCtQj rERawndlToOOUTJSCXTi2A3pgcb192ivb5qNUgnqGryxABOQP0j0MUo3MpFrbxLLu489 1sKA== X-Gm-Message-State: AHYfb5hF1b/KVpq+/ev01mC0UJ3vBfpGQ61C/L9Ob4hTAnPkpW0JjqVn SOOdTFTLIZszoVS3 X-Received: by 10.28.40.69 with SMTP id o66mr6201025wmo.164.1503337449519; Mon, 21 Aug 2017 10:44:09 -0700 (PDT) Received: from localhost.localdomain ([2a02:aa16:5782:c100:1208:b1ff:fee6:d811]) by smtp.gmail.com with ESMTPSA id y8sm5942458wmg.12.2017.08.21.10.44.08 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Mon, 21 Aug 2017 10:44:08 -0700 (PDT) From: =?UTF-8?q?Martin=20=C3=85gren?= Cc: git@vger.kernel.org, Jeff King Subject: [PATCH v2 4/4] ThreadSanitizer: add suppressions Date: Mon, 21 Aug 2017 19:43:48 +0200 Message-Id: <09bbbcd1429a28774ea2d8c67ef6106ab558c296.1503323391.git.martin.agren@gmail.com> X-Mailer: git-send-email 2.14.1.151.gdfeca7a7e In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit To: unlisted-recipients:; (no To-header on input) Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Add a file .tsan-suppressions and list two functions in it: want_color() and transfer_debug(). Both of these use the pattern static int foo = -1; if (foo < 0) foo = bar(); where bar always returns the same non-negative value. This can cause ThreadSanitizer to diagnose a race when foo is written from two threads. That is indeed a race, although it arguably doesn't matter in practice since it's always the same value that is written. Add NEEDSWORK-comments to the functions so that this problem is not forever swept way under the carpet. The suppressions-file is used by setting the environment variable TSAN_OPTIONS to, e.g., "suppressions=$(pwd)/.tsan-suppressions". Observe that relative paths such as ".tsan-suppressions" might not work. Signed-off-by: Martin Ågren --- v2: added NEEDSWORK; reworded the comments in the new file color.c | 7 +++++++ transport-helper.c | 7 +++++++ .tsan-suppressions | 10 ++++++++++ 3 files changed, 24 insertions(+) create mode 100644 .tsan-suppressions diff --git a/color.c b/color.c index 7aa8b076f..9ccd954d6 100644 --- a/color.c +++ b/color.c @@ -338,6 +338,13 @@ static int check_auto_color(void) int want_color(int var) { + /* + * NEEDSWORK: This function is sometimes used from multiple threads, and + * we end up using want_auto racily. That "should not matter" since + * we always write the same value, but it's still wrong. This function + * is listed in .tsan-suppressions for the time being. + */ + static int want_auto = -1; if (var < 0) diff --git a/transport-helper.c b/transport-helper.c index 8f68d69a8..f50b34df2 100644 --- a/transport-helper.c +++ b/transport-helper.c @@ -1117,6 +1117,13 @@ int transport_helper_init(struct transport *transport, const char *name) __attribute__((format (printf, 1, 2))) static void transfer_debug(const char *fmt, ...) { + /* + * NEEDSWORK: This function is sometimes used from multiple threads, and + * we end up using debug_enabled racily. That "should not matter" since + * we always write the same value, but it's still wrong. This function + * is listed in .tsan-suppressions for the time being. + */ + va_list args; char msgbuf[PBUFFERSIZE]; static int debug_enabled = -1; diff --git a/.tsan-suppressions b/.tsan-suppressions new file mode 100644 index 000000000..8c85014a0 --- /dev/null +++ b/.tsan-suppressions @@ -0,0 +1,10 @@ +# Suppressions for ThreadSanitizer (tsan). +# +# This file is used by setting the environment variable TSAN_OPTIONS to, e.g., +# "suppressions=$(pwd)/.tsan-suppressions". Observe that relative paths such as +# ".tsan-suppressions" might not work. + +# A static variable is written to racily, but we always write the same value, so +# in practice it (hopefully!) doesn't matter. +race:^want_color$ +race:^transfer_debug$ -- 2.14.1.151.gdfeca7a7e