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 A9818C7619A for ; Mon, 27 Mar 2023 13:36:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229619AbjC0NgE (ORCPT ); Mon, 27 Mar 2023 09:36:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57670 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230341AbjC0NgD (ORCPT ); Mon, 27 Mar 2023 09:36:03 -0400 Received: from mail-pf1-x431.google.com (mail-pf1-x431.google.com [IPv6:2607:f8b0:4864:20::431]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C978344B0 for ; Mon, 27 Mar 2023 06:36:01 -0700 (PDT) Received: by mail-pf1-x431.google.com with SMTP id c4so5722230pfl.0 for ; Mon, 27 Mar 2023 06:36:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20210112.gappssmtp.com; s=20210112; t=1679924161; x=1682516161; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=qk8mEmXhmkij8TFHjllJ20n3reyRkxB51/J3Ax/p7n0=; b=2Gk3ezhjrVnvJZJD1N/OMSWUjmgh1iwcVRjCz3DVGcgZG92GdNw+CFM9I06aJL1Rbf 9NqFfADa9ykfd5bBOwhSyG0ym1BtUuN/beUzlVFRsLBOSJtawH2gL3PyCrmIF1Z/kzt4 JFDp6r4h0ugpkkN6cwOPAx41YYDfcJ35zyGj7VjIblrpEsNh3c536YpA5SEerN46g4JA /WswQ/cu0wfCyUv1eUNyjHrYQ0E0DSbfZDeQQwJ+nsbSjpbt+O8mGUgB/GaA13QRTXqr dTq5nUwrR/dOIIftlofcdDGRnR8Oy+6pSozGNuNx/5/OGTSeu64G9eE1Vym6qk52a8Td oUqg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1679924161; x=1682516161; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=qk8mEmXhmkij8TFHjllJ20n3reyRkxB51/J3Ax/p7n0=; b=ePuHVFcsOmuPA7Op4CHChCbppXEQm5spEuWy4t8TiXNj9XLIK4/63eUy6GDioVpEkQ //7pV6kapja5lFPL5+3f5KgAj/dUDLlXZwVkuK6G3MgPiUSOgttTjoOQTGOzPi4VUU7J 9HG38AawG0SkaM14TUBzSmPy5TLi/y1lkGlASaEudXsd700kdHobq48BU2/sjMFlnzig AEHEAmVfxhWz830U51iiyxv30oX3aTIoxr1dAYLFDVNvZc1xnbygP8JX/Zui0oqd8jHu Psx/w4PoY7mJcTslpBH1RI66v4y7lfEk5antcv+mAqRi9Zg840I+qcy217dwVvs5Sils U0fw== X-Gm-Message-State: AAQBX9eLUgzCNQCvX3m+GtCHfQU2vyMG3U1BJgU6OIPkko3NvSCdATv7 NgInkNdGCc/dALoDIVWnjNCKzv8Gw97bqTPRRzNF+g== X-Google-Smtp-Source: AKy350Zz+gdHQ/wN2j/B1WoIVJSpBA6wWKADWT0oO0RAhFL6sv6RQnVfETBicFxwyjWuAV1b5VeS/A== X-Received: by 2002:aa7:8b1a:0:b0:628:630:a374 with SMTP id f26-20020aa78b1a000000b006280630a374mr10585278pfd.2.1679924160975; Mon, 27 Mar 2023 06:36:00 -0700 (PDT) Received: from [192.168.1.136] ([198.8.77.157]) by smtp.gmail.com with ESMTPSA id p26-20020aa7861a000000b006249928aba2sm19038827pfn.59.2023.03.27.06.36.00 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 27 Mar 2023 06:36:00 -0700 (PDT) Message-ID: Date: Mon, 27 Mar 2023 07:35:59 -0600 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:102.0) Gecko/20100101 Thunderbird/102.9.0 Subject: Re: [Syzkaller & bisect] There is "io_poll_remove_entries" NULL pointer BUG in v6.3-rc4 kernel Content-Language: en-US To: Pengfei Xu Cc: stable@vger.kernel.org, linux-kernel@vger.kernel.org, heng.su@intel.com, lkp@intel.com References: From: Jens Axboe In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On 3/27/23 12:08?AM, Pengfei Xu wrote: > Hi Jens Axboe and kernel experts, > > Platform: x86 platforms > There is "io_poll_remove_entries" NULL pointer BUG in v6.3-rc4 kernel. > > All detailed log: https://github.com/xupengfe/syzkaller_logs/tree/main/230327_041425_io_poll_remove_entries > Syzkaller reproduced code: https://github.com/xupengfe/syzkaller_logs/blob/main/230327_041425_io_poll_remove_entries/repro.c > Syzkaller analysis report0: https://github.com/xupengfe/syzkaller_logs/blob/main/230327_041425_io_poll_remove_entries/report0 > Syzkaller analysis status: https://github.com/xupengfe/syzkaller_logs/blob/main/230327_041425_io_poll_remove_entries/repro.stats > v6.3-rc4 issue dmesg: https://github.com/xupengfe/syzkaller_logs/blob/main/230327_041425_io_poll_remove_entries/v63rc4_reproduce_dmesg.log > Kconfig: https://github.com/xupengfe/syzkaller_logs/blob/main/230327_041425_io_poll_remove_entries/kconfig_origin > Bisect info: https://github.com/xupengfe/syzkaller_logs/blob/main/230327_041425_io_poll_remove_entries/bisect_info.log > > It could be reproduced in v6.3-rc3 and v6.3-rc4 kernel, and bisected between > v6.3-rc3 and v5.11 kernel, bad commit was: > " > c16bda37594f83147b167d381d54c010024efecf > io_uring/poll: allow some retries for poll triggering spuriously > " > After reverted above commit on top of v6.3-rc3 kernel, this issue was gone. This should probably fix it, though I do wonder why this can only trigger after that patch. Seems like it would've been possible before too. diff --git a/io_uring/poll.c b/io_uring/poll.c index 795facbd0e9f..90555a22a900 100644 --- a/io_uring/poll.c +++ b/io_uring/poll.c @@ -600,7 +600,8 @@ static int __io_arm_poll_handler(struct io_kiocb *req, mask = vfs_poll(req->file, &ipt->pt) & poll->events; if (unlikely(ipt->error || !ipt->nr_entries)) { - io_poll_remove_entries(req); + if (ipt->nr_entries) + io_poll_remove_entries(req); if (!io_poll_can_finish_inline(req, ipt)) { io_poll_mark_cancelled(req); -- Jens Axboe