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=-5.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 E3A84C48BD1 for ; Thu, 10 Jun 2021 19:08:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B2524613B0 for ; Thu, 10 Jun 2021 19:08:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230269AbhFJTKU (ORCPT ); Thu, 10 Jun 2021 15:10:20 -0400 Received: from alexa-out.qualcomm.com ([129.46.98.28]:32214 "EHLO alexa-out.qualcomm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230077AbhFJTKU (ORCPT ); Thu, 10 Jun 2021 15:10:20 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=quicinc.com; i=@quicinc.com; q=dns/txt; s=qcdkim; t=1623352104; x=1654888104; h=subject:to:cc:references:from:message-id:date: mime-version:in-reply-to:content-transfer-encoding; bh=WKtah1s5N0nQHR2zrg8vHuHf2WJcWUP5gtf2DlwFVFk=; b=xNN8wcM/7zTxJDKNodSJVKw2zAy2MZUvN7elDN+X/fGfZgLO7uUq8meL EqB8bH7W0EOa08/MGYcMLTFKRQB9uCEuBiRTkv+XnOobVj3M8q52oy9O9 CRk+FAvaC6eKyv0hptIoUubiBRi2F4bsiahKX0uN2gVUeXnu3hYS4ZzZ7 Y=; Received: from ironmsg-lv-alpha.qualcomm.com ([10.47.202.13]) by alexa-out.qualcomm.com with ESMTP; 10 Jun 2021 12:08:23 -0700 X-QCInternal: smtphost Received: from nalasexr03e.na.qualcomm.com ([10.49.195.114]) by ironmsg-lv-alpha.qualcomm.com with ESMTP/TLS/AES256-SHA; 10 Jun 2021 12:08:22 -0700 Received: from [10.111.162.47] (10.80.80.8) by nalasexr03e.na.qualcomm.com (10.49.195.114) with Microsoft SMTP Server (TLS) id 15.0.1497.18; Thu, 10 Jun 2021 12:08:20 -0700 Subject: Re: [RFC][PATCHSET] iov_iter work To: Al Viro CC: Linus Torvalds , , , David Sterba , Miklos Szeredi , Anton Altaparmakov , David Howells , Matthew Wilcox , Pavel Begunkov References: <7433441f-b175-8484-240c-d1498c8c43f2@quicinc.com> From: Qian Cai Message-ID: <1337e3ea-6984-7f70-98cc-f20a43e659d2@quicinc.com> Date: Thu, 10 Jun 2021 15:08:19 -0400 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.80.80.8] X-ClientProxiedBy: nasanexm03b.na.qualcomm.com (10.85.0.98) To nalasexr03e.na.qualcomm.com (10.49.195.114) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 6/10/2021 11:35 AM, Al Viro wrote: > On Thu, Jun 10, 2021 at 10:29:59AM -0400, Qian Cai wrote: > >> Al, a quick fuzzing on today's linux-next triggered this. I never saw this before, so I am wondering if this is anything to do with this series. I could try to narrow it down and bisect if necessary. Any thoughts? > > Do you have a reproducer? I have no idea how reproducible this is, but it was triggered by running the fuzzing within a half-hour. $ trinity -C 16 > call of memcpy_from_skb(), calling copy_from_iter_full(), which > calls iov_iter_revert() on failure now... > > Bloody hell. Incremental, to be folded in: This patch is running good so far. I'll report back if things changed.