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=-2.6 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_HI,RCVD_IN_SORBS_SPAM, RP_MATCHES_RCVD 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 D5C7E202A0 for ; Wed, 1 Nov 2017 20:45:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755218AbdKAUp3 (ORCPT ); Wed, 1 Nov 2017 16:45:29 -0400 Received: from mail-wr0-f193.google.com ([209.85.128.193]:51582 "EHLO mail-wr0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755173AbdKAUp2 (ORCPT ); Wed, 1 Nov 2017 16:45:28 -0400 Received: by mail-wr0-f193.google.com with SMTP id j15so3053889wre.8 for ; Wed, 01 Nov 2017 13:45:28 -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=+Vyv0L+khzpd1rgquTfv1PNmnK9OI6abrAUccVLtjvQ=; b=YOXVQzXif+TW+MsjHk8o5SrRN9LrfPz4ti7RWFrKdkoOelPdMA12YfaPDJ8Df/Fw5x dh4fSkKYWQjFaFo06eT/lKxYWXjNBj1KkHFdUVm8Xu/QsWwdciLQjyYK1uFLsJSPNn+2 ji+4pkpHYUYeBzgp0Yr38T7jBKsddHvN6BUtCA9+CKd/I3wYjJU+QYf8JYPFF31hS5fw XCQPWIVjAGuqMG5Rcs/ReY+gBo5EU1bIZQwX9tC805Ll+LoQZFX457UL415TpnI47KAr VSQQQxt4GxMMo3RwXTJJrfE1t+88wxwLkqQPZoMFl76RdGsIXoZrleuQrPtabniDzAR5 haCw== 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=+Vyv0L+khzpd1rgquTfv1PNmnK9OI6abrAUccVLtjvQ=; b=XIAY4q6D69vaY1wq8nJTnCtfTMO2GPKRy36bUEC2QTZ0u3TI3YBynf5VHKYKgS0xuu NWbEGw8dFTIHADsu5B4vje/1DtmmpRFmp8x2XVxYVpU3BGlgIT9eQvmgqJuyQMDUv1c9 6Tad5LqtYcORu/wFrWWfIX+8X8zVdwQuau1Cxes8TiGYBKPPrvaR9Zu7q9PXeUNJm10H vVtel1qLv6TwtI+hOgmIm7SvLDzvkLSFXMFFWmYf2GxCa3aIZCytqmus8+5WSQ4W08VB ZZqPnfCNdZOuTqHwdQ04BiXLD+LLDZyW5YVGSIy+ZQvn9f04JB5QaSxF6GtB82QbduFc LXnw== X-Gm-Message-State: AMCzsaX3r6SK3+SjJ6O6yNN8LfgKhy9+acy1SGm/NjqziAWcpUbKT3dL pVhUn3Wq3F4zcb2Zh7BIthcx2mFgYbk= X-Google-Smtp-Source: ABhQp+T/CKPAQ1DxkIDw7Nqsgw+soLZmEDszG9XUucjbGmfpoJAZZjKMLW1Z6SLsYAyA+sbO5qC5pg== X-Received: by 10.223.152.16 with SMTP id v16mr798771wrb.108.1509569127167; Wed, 01 Nov 2017 13:45:27 -0700 (PDT) Received: from localhost.localdomain ([2a02:aa16:5782:c100:c938:fbb7:46f8:2405]) by smtp.gmail.com with ESMTPSA id x82sm1248582wmg.7.2017.11.01.13.45.25 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Wed, 01 Nov 2017 13:45:26 -0700 (PDT) From: =?UTF-8?q?Martin=20=C3=85gren?= To: git@vger.kernel.org Cc: Brandon Williams , Jeff King Subject: [PATCH v2] grep: take the read-lock when adding a submodule Date: Wed, 1 Nov 2017 21:45:06 +0100 Message-Id: <20171101204506.5481-1-martin.agren@gmail.com> X-Mailer: git-send-email 2.15.0.415.gac1375d7e In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org With --recurse-submodules, we add each submodule that we encounter to the list of alternate object databases. With threading, our changes to the list are not protected against races. Indeed, ThreadSanitizer reports a race when we call `add_to_alternates_memory()` around the same time that another thread is reading in the list through `read_sha1_file()`. Take the grep read-lock while adding the submodule. The lock is used to serialize uses of non-thread-safe parts of Git's API, including `read_sha1_file()`. Helped-by: Brandon Williams Signed-off-by: Martin Ågren --- Many thanks to Brandon for showing how this should have been done. builtin/grep.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/builtin/grep.c b/builtin/grep.c index 2d65f27d0..5a6cfe6b4 100644 --- a/builtin/grep.c +++ b/builtin/grep.c @@ -431,7 +431,9 @@ static int grep_submodule(struct grep_opt *opt, struct repository *superproject, * store is no longer global and instead is a member of the repository * object. */ + grep_read_lock(); add_to_alternates_memory(submodule.objectdir); + grep_read_unlock(); if (oid) { struct object *object; -- 2.15.0.415.gac1375d7e