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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CFC3FC433F5 for ; Tue, 17 May 2022 12:25:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345986AbiEQMZc (ORCPT ); Tue, 17 May 2022 08:25:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51854 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345981AbiEQMZW (ORCPT ); Tue, 17 May 2022 08:25:22 -0400 Received: from mail-pl1-x629.google.com (mail-pl1-x629.google.com [IPv6:2607:f8b0:4864:20::629]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A59F7483A1 for ; Tue, 17 May 2022 05:25:19 -0700 (PDT) Received: by mail-pl1-x629.google.com with SMTP id c9so17201904plh.2 for ; Tue, 17 May 2022 05:25:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20210112.gappssmtp.com; s=20210112; h=message-id:date:mime-version:user-agent:subject:content-language:to :cc:references:from:in-reply-to:content-transfer-encoding; bh=IrIkpbmuHKrrFsBUcjgqjjP93rmoX31NTGTCvMbPP4Y=; b=NBnYbNP+J+JpzURJ6Bf3exMaOrCVSX0qu7AbJU/g5utF6PrfU0h0Z3iopcGlBvlMaC GPNDDKiTgAOxADt5l7Ze5F7iIYg0EeQWUaoI2NkGxf4FSSIbbwRwWPxUNQHvoCM9b3Fd RbW2rvRzAo+Kf46ym8S/g4GDjZXkuFzjGEU4H3BLIEeBLDIPm0KvzYVaZDnPOKrlJalB LrmgUM3YBO579B1Rq/5vGNGBTpVc80eg0Z+iMNjWSBL4pDDBAUriFACI5YQWiy0QYXAt foThqezPvxPmiwv0HisQ9imencOBCyxh/lJ9aQxB2Y3NH3Iqr81CvzDrcRTWh0DqwQ6S gtwg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=IrIkpbmuHKrrFsBUcjgqjjP93rmoX31NTGTCvMbPP4Y=; b=PqhQ9OOcNgl2azjyAlxrSvXz952Gz2L2PIypG5Tv7zD1NmrwDqdqey9toE5F1GZkVB 2ZXWpj03y/tx/j0tBFkt9mZRifbke9453ozU1BG9X7FVPgrfFEmZXtb4JLyCcGLiLA7K Tz0n9ZqZ29Ow7pCMdS5cg3+Uv54tgpbGGZTW2qH4e6P7rXRnuI7AbaRuMYXMn1lvKlL4 cQCJdl5hXgMsnJyrm/3OlkBT4erh1XiEsqNcPkOnA6OPpCIx7bzKCp6/1WOioA47vwHc WusBbMSh/QelOytfKI2BjQKUBDL5hZ+zQkVZwkp9QHjOZZhqLS+Olx0fFkGCdNdG/zeJ TIIg== X-Gm-Message-State: AOAM532KabS1RhoVE4frmcKRPD/s0QtpY4o0iBpg8fJZDr3R2ENfiocY 2WD1sAyixvKdgpq60OWdqNhAbg== X-Google-Smtp-Source: ABdhPJz+aD1l14DXBGFrAfTzh04KGDyvg7BAjkXVZnm/y60aPmtYxeB2+8D7hg4SfmHCGxIXoIkF7g== X-Received: by 2002:a17:90b:4a51:b0:1df:7617:bcfb with SMTP id lb17-20020a17090b4a5100b001df7617bcfbmr6584943pjb.207.1652790319084; Tue, 17 May 2022 05:25:19 -0700 (PDT) Received: from [192.168.1.100] ([198.8.77.157]) by smtp.gmail.com with ESMTPSA id b8-20020a17090a990800b001df6216e89dsm1542814pjp.28.2022.05.17.05.25.18 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 17 May 2022 05:25:18 -0700 (PDT) Message-ID: Date: Tue, 17 May 2022 06:25:17 -0600 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:91.0) Gecko/20100101 Thunderbird/91.8.1 Subject: Re: [REPORT] Use-after-free Read in __fdget_raw in v5.10.y Content-Language: en-US To: Lee Jones Cc: Pavel Begunkov , io-uring@vger.kernel.org, linux-kernel@vger.kernel.org References: <97cba3e1-4ef7-0a17-8456-e0787d6702c6@kernel.dk> From: Jens Axboe In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On 5/17/22 6:24 AM, Lee Jones wrote: > On Tue, 17 May 2022, Jens Axboe wrote: > >> On 5/17/22 5:41 AM, Lee Jones wrote: >>> Good afternoon Jens, Pavel, et al., >>> >>> Not sure if you are presently aware, but there appears to be a >>> use-after-free issue affecting the io_uring worker driver (fs/io-wq.c) >>> in Stable v5.10.y. >>> >>> The full sysbot report can be seen below [0]. >>> >>> The C-reproducer has been placed below that [1]. >>> >>> I had great success running this reproducer in an infinite loop. >>> >>> My colleague reverse-bisected the fixing commit to: >>> >>> commit fb3a1f6c745ccd896afadf6e2d6f073e871d38ba >>> Author: Jens Axboe >>> Date: Fri Feb 26 09:47:20 2021 -0700 >>> >>> io-wq: have manager wait for all workers to exit >>> >>> Instead of having to wait separately on workers and manager, just have >>> the manager wait on the workers. We use an atomic_t for the reference >>> here, as we need to start at 0 and allow increment from that. Since the >>> number of workers is naturally capped by the allowed nr of processes, >>> and that uses an int, there is no risk of overflow. >>> >>> Signed-off-by: Jens Axboe >>> >>> fs/io-wq.c | 30 ++++++++++++++++++++++-------- >>> 1 file changed, 22 insertions(+), 8 deletions(-) >> >> Does this fix it: >> >> commit 886d0137f104a440d9dfa1d16efc1db06c9a2c02 >> Author: Jens Axboe >> Date: Fri Mar 5 12:59:30 2021 -0700 >> >> io-wq: fix race in freeing 'wq' and worker access >> >> Looks like it didn't make it into 5.10-stable, but we can certainly >> rectify that. > > Thanks for your quick response Jens. > > This patch doesn't apply cleanly to v5.10.y. This is probably why it never made it into 5.10-stable :-/ > I'll have a go at back-porting it. Please bear with me. Let me know if you into issues with that and I can help out. -- Jens Axboe