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=-5.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 B9B39C43387 for ; Wed, 2 Jan 2019 16:55:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 85545218A4 for ; Wed, 2 Jan 2019 16:55:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1546448133; bh=nsg3WItb8MnLGMchxTHG4VBWqCy2pvowcKWW6wdohHk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=J77W7HBVodm+uaMdGzIkvH1+nlMNqxha1bVLc0XSMRPMvbTcoP+lQj1yu9pq0KWek FsNKQvNgyOg+nDBgJS7s9zcSu6ip+XI75kLHAeQTlBB5Hy3NdUyFjvAIg5GR7rQWH5 WwnFr+lP4MI63EcO/J2gWuuhLbeIjI3TxME2+Wmw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730527AbfABQzc (ORCPT ); Wed, 2 Jan 2019 11:55:32 -0500 Received: from mail-yb1-f174.google.com ([209.85.219.174]:41044 "EHLO mail-yb1-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728720AbfABQzc (ORCPT ); Wed, 2 Jan 2019 11:55:32 -0500 Received: by mail-yb1-f174.google.com with SMTP id j10so9356305ybj.8; Wed, 02 Jan 2019 08:55:31 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=Q1UdSA/joYtOsFTB+m/lzbdC32xblqmOjKAMKTyp0Hw=; b=u3CnmYgOnClSuo91qZ0Gs2/sdp0DFdkIeWeuhWM5YCwphhDZlVNypqm2xmScQPG8uG z8k8P3UTBaCTGEEeANk0iYoFE5h6oBdGmL8uLgU56vcg6mUnx1u6Ph9S/E7n5IiMC7EF aNU98VEfl2ozZQ9xc2pq2AtbgIFmJOoW5w3vEKh74zP5PZ2Q9uhL0mLfTgTzK1SE1EQC 1EWc9hXOynVuwwTAERrhezzaU8KfqHVxAyrBsm6EX99YNu4gRlnxrY0iZR8JYWIfUZPV /47kY35lsrTr+/wqhpV6QihbwxC8FvESfp3+m+HkEJ3ndYBjhusw3ShDbUUq0KfbEBYJ pgGg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to:user-agent; bh=Q1UdSA/joYtOsFTB+m/lzbdC32xblqmOjKAMKTyp0Hw=; b=s91COYVh+UfpzQbA7fHS4tqMJXbPBFp8nMIZX20reDr3EQ7OdhzE1VtU92G858c1yl 3u0seZ7TcaBMNHoDuCu+gjWhfg0EdFFpZoUrTAsN7rxP88mS5DjWUmqDAl6Wy1SmemVE LrrrR0ZCBYxMFKEUHXqPifCFS3wQuqDu/RDKy0E+BcH5M3I0EFiSQ8wsSW3cNH+OKNbo 7wjP7pyM32UUFJnR53vgDcroYPT8AoC1jNK4hqUDQHqBp8AMsTJ1Vh0bEARVWUYe3Pot GAAdmVFP6odUBPMqAP+m5/DVhiuDdJWBROldmDRdDxUnWkExT1vllsRPby3/0liWRcfW LZ0g== X-Gm-Message-State: AJcUukfE3oeEyCXZu2yrTMFoc2vD9nPSfxfgwlvFmC3c0e9aGxM8Rd/1 4RgvKx9EhZGxDX575PVmX4w= X-Google-Smtp-Source: AFSGD/WX6xYTHah54FHMRhtB6S6IN7sw58CcAKkPGTS+EmL9Ws0t7vjoOUT1ME4KskYcyHbWyRC5zQ== X-Received: by 2002:a25:7dc5:: with SMTP id y188mr44401322ybc.91.1546448131258; Wed, 02 Jan 2019 08:55:31 -0800 (PST) Received: from localhost ([2620:10d:c091:200::6:f03d]) by smtp.gmail.com with ESMTPSA id w2sm39214353ywl.10.2019.01.02.08.55.29 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 02 Jan 2019 08:55:29 -0800 (PST) Date: Wed, 2 Jan 2019 08:55:28 -0800 From: Tejun Heo To: Tetsuo Handa Cc: Zefan Li , syzbot , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, viro@zeniv.linux.org.uk Subject: Re: WARNING: lock held when returning to user space in grab_super Message-ID: <20190102165528.GT2509588@devbig004.ftw2.facebook.com> References: <000000000000638c1b057e787822@google.com> <20190102161640.GS2509588@devbig004.ftw2.facebook.com> <19260f8b-d831-9a9a-5315-1f4353dadc9b@i-love.sakura.ne.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <19260f8b-d831-9a9a-5315-1f4353dadc9b@i-love.sakura.ne.jp> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 03, 2019 at 01:49:55AM +0900, Tetsuo Handa wrote: > kernfs_node_dentry() calls lookup_one_len_unlocked() which involves > memory allocation, and memory allocation fault injection made > lookup_one_len_unlocked() fail, and thus kernfs_node_dentry() failed. > What's strange? So, kernfs_node_dentry() is called on the root kn, which should trigger "if (!kn->parent) return dentry" in kernfs_node_dentry(), so it shouldn't reach lookup_on_len_unlocked(). Oh I see. This is the namespaced mount path, so kn can be non-root. Will fix it. Thanks. -- tejun