From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4ED4DC2BA83 for ; Mon, 10 Feb 2020 02:00:57 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id E3F4C2082E for ; Mon, 10 Feb 2020 02:00:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="TCcQadNU" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E3F4C2082E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 3F6246B0088; Sun, 9 Feb 2020 21:00:56 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 3A7CD6B0089; Sun, 9 Feb 2020 21:00:56 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2BDCD6B008A; Sun, 9 Feb 2020 21:00:56 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0120.hostedemail.com [216.40.44.120]) by kanga.kvack.org (Postfix) with ESMTP id 14C816B0088 for ; Sun, 9 Feb 2020 21:00:56 -0500 (EST) Received: from smtpin25.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id B43D3181AC9BF for ; Mon, 10 Feb 2020 02:00:55 +0000 (UTC) X-FDA: 76472564070.25.class50_80d61588fe18 X-HE-Tag: class50_80d61588fe18 X-Filterd-Recvd-Size: 2690 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf08.hostedemail.com (Postfix) with ESMTP for ; Mon, 10 Feb 2020 02:00:55 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 1462D20658; Mon, 10 Feb 2020 02:00:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581300054; bh=41HPUlLDy++8Av8WXW4W6NplVfV5KoKoBojlx/mJKfo=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=TCcQadNU0BHQvXf6A6qbnhCWmpZm9KT7AOHbvNFnOPLuyfou6rRmF8elh3LA7efZF rxEJxy/y9Z4J9QTktVoVh6XZr7w22ExpTQRsqG2kj5o2OmMy9psGFF4P9a7o6fqxTb 1dAOTs85lPqmn7GtxI8A+o7Mh1RNdMDJuX/HEdgA= Date: Sun, 9 Feb 2020 18:00:53 -0800 From: Andrew Morton To: Qian Cai Cc: elver@google.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Paul E. McKenney Subject: Re: [PATCH -next] mm/swap_state: mark various intentional data races Message-Id: <20200209180053.784806e3bf028caa8bc584b3@linux-foundation.org> In-Reply-To: <20200207003715.1578-1-cai@lca.pw> References: <20200207003715.1578-1-cai@lca.pw> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, 6 Feb 2020 19:37:15 -0500 Qian Cai wrote: > swap_cache_info.* could be accessed concurrently as noticed by > KCSAN, > > BUG: KCSAN: data-race in lookup_swap_cache / lookup_swap_cache > > write to 0xffffffff85517318 of 8 bytes by task 94138 on cpu 101: > lookup_swap_cache+0x12e/0x460 > lookup_swap_cache at mm/swap_state.c:322 > do_swap_page+0x112/0xeb0 > __handle_mm_fault+0xc7a/0xd00 > handle_mm_fault+0xfc/0x2f0 > do_page_fault+0x263/0x6f9 > page_fault+0x34/0x40 > > ... > > --- a/mm/swap_state.c > +++ b/mm/swap_state.c > @@ -58,8 +58,8 @@ static bool enable_vma_readahead __read_mostly = true; > #define GET_SWAP_RA_VAL(vma) \ > (atomic_long_read(&(vma)->swap_readahead_info) ? : 4) > > -#define INC_CACHE_INFO(x) do { swap_cache_info.x++; } while (0) > -#define ADD_CACHE_INFO(x, nr) do { swap_cache_info.x += (nr); } while (0) > +#define INC_CACHE_INFO(x) data_race(swap_cache_info.x++) > +#define ADD_CACHE_INFO(x, nr) data_race(swap_cache_info.x += (nr)) The data_race() macro appears to be stuck in Paul's linx-next tree. Can we expect this to be mainlined soon, or is there an issue?