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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 6B295C2BB1D for ; Fri, 10 Apr 2020 02:53:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4BE3520A8B for ; Fri, 10 Apr 2020 02:53:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726657AbgDJCxC (ORCPT ); Thu, 9 Apr 2020 22:53:02 -0400 Received: from mail-pf1-f196.google.com ([209.85.210.196]:44939 "EHLO mail-pf1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726538AbgDJCxC (ORCPT ); Thu, 9 Apr 2020 22:53:02 -0400 Received: by mail-pf1-f196.google.com with SMTP id b72so468380pfb.11; Thu, 09 Apr 2020 19:53:02 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:autocrypt :message-id:date:user-agent:mime-version:in-reply-to :content-language:content-transfer-encoding; bh=SgPrptd85zUfqS0Tu1fnyBZ8OdxDfCTb8OSMKyUvV4o=; b=mkWwhxNwgcCKP5hHFefI8osVR0u8mhcxGql0ursk9GlTyzUBJjmU6i3pkSnkmgyMjY TFYcItOXtS93TVcveJEi7lJYQRRKjBCMZ1eH1jswij1MFqH1mLDWp97uaon1syBGonQ3 zUpssXvfq27Rf4NDpZuyGJ7LAbtohnKGq/M944FchvJ7YV/afWD3IVAGYBakB3gI4T/4 QorO9T2mSacCX9trVUmwpc5JCMDI5FA4CEAU2TaNMQvKb2AyvAijSaJNsMC491dsSfGj 3VJTt+oR/2z58eSBuCxaniWAc+ydIDLN7w2arKKYwh+Hj2IXWPDJd4eO3Nk9Nqb5mlpf 3eHg== X-Gm-Message-State: AGi0PuZmS3jFgOPWFhhDU6qyROXYMSxJkfyhcF00RNKo6po74bQMisLL R6ysGtHrR0xV2SXSANklzJ0= X-Google-Smtp-Source: APiQypKPxb5CXryb5BtNXPr5kdp0rt+Ym2cknSQtkUoHtL2oJR+gGL/isM4KsNE0SJYVfopnhV7zhA== X-Received: by 2002:a62:2b05:: with SMTP id r5mr2738916pfr.120.1586487181522; Thu, 09 Apr 2020 19:53:01 -0700 (PDT) Received: from ?IPv6:2601:647:4000:d7:ed4e:1b14:7fc4:cd73? ([2601:647:4000:d7:ed4e:1b14:7fc4:cd73]) by smtp.gmail.com with ESMTPSA id c21sm408791pgn.84.2020.04.09.19.52.59 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 09 Apr 2020 19:53:00 -0700 (PDT) Subject: Re: [RFC v2 2/5] blktrace: fix debugfs use after free To: Luis Chamberlain , axboe@kernel.dk, viro@zeniv.linux.org.uk, gregkh@linuxfoundation.org, rostedt@goodmis.org, mingo@redhat.com, jack@suse.cz, ming.lei@redhat.com, nstange@suse.de, akpm@linux-foundation.org Cc: mhocko@suse.com, yukuai3@huawei.com, linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Omar Sandoval , Hannes Reinecke , Michal Hocko , syzbot+603294af2d01acfdd6da@syzkaller.appspotmail.com References: <20200409214530.2413-1-mcgrof@kernel.org> <20200409214530.2413-3-mcgrof@kernel.org> From: Bart Van Assche Autocrypt: addr=bvanassche@acm.org; prefer-encrypt=mutual; keydata= mQENBFSOu4oBCADcRWxVUvkkvRmmwTwIjIJvZOu6wNm+dz5AF4z0FHW2KNZL3oheO3P8UZWr LQOrCfRcK8e/sIs2Y2D3Lg/SL7qqbMehGEYcJptu6mKkywBfoYbtBkVoJ/jQsi2H0vBiiCOy fmxMHIPcYxaJdXxrOG2UO4B60Y/BzE6OrPDT44w4cZA9DH5xialliWU447Bts8TJNa3lZKS1 AvW1ZklbvJfAJJAwzDih35LxU2fcWbmhPa7EO2DCv/LM1B10GBB/oQB5kvlq4aA2PSIWkqz4 3SI5kCPSsygD6wKnbRsvNn2mIACva6VHdm62A7xel5dJRfpQjXj2snd1F/YNoNc66UUTABEB AAG0JEJhcnQgVmFuIEFzc2NoZSA8YnZhbmFzc2NoZUBhY20ub3JnPokBOQQTAQIAIwUCVI67 igIbAwcLCQgHAwIBBhUIAgkKCwQWAgMBAh4BAheAAAoJEHFcPTXFzhAJ8QkH/1AdXblKL65M Y1Zk1bYKnkAb4a98LxCPm/pJBilvci6boefwlBDZ2NZuuYWYgyrehMB5H+q+Kq4P0IBbTqTa jTPAANn62A6jwJ0FnCn6YaM9TZQjM1F7LoDX3v+oAkaoXuq0dQ4hnxQNu792bi6QyVdZUvKc macVFVgfK9n04mL7RzjO3f+X4midKt/s+G+IPr4DGlrq+WH27eDbpUR3aYRk8EgbgGKvQFdD CEBFJi+5ZKOArmJVBSk21RHDpqyz6Vit3rjep7c1SN8s7NhVi9cjkKmMDM7KYhXkWc10lKx2 RTkFI30rkDm4U+JpdAd2+tP3tjGf9AyGGinpzE2XY1K5AQ0EVI67igEIAKiSyd0nECrgz+H5 PcFDGYQpGDMTl8MOPCKw/F3diXPuj2eql4xSbAdbUCJzk2ETif5s3twT2ER8cUTEVOaCEUY3 eOiaFgQ+nGLx4BXqqGewikPJCe+UBjFnH1m2/IFn4T9jPZkV8xlkKmDUqMK5EV9n3eQLkn5g lco+FepTtmbkSCCjd91EfThVbNYpVQ5ZjdBCXN66CKyJDMJ85HVr5rmXG/nqriTh6cv1l1Js T7AFvvPjUPknS6d+BETMhTkbGzoyS+sywEsQAgA+BMCxBH4LvUmHYhpS+W6CiZ3ZMxjO8Hgc ++w1mLeRUvda3i4/U8wDT3SWuHcB3DWlcppECLkAEQEAAYkBHwQYAQIACQUCVI67igIbDAAK CRBxXD01xc4QCZ4dB/0QrnEasxjM0PGeXK5hcZMT9Eo998alUfn5XU0RQDYdwp6/kMEXMdmT oH0F0xB3SQ8WVSXA9rrc4EBvZruWQ+5/zjVrhhfUAx12CzL4oQ9Ro2k45daYaonKTANYG22y //x8dLe2Fv1By4SKGhmzwH87uXxbTJAUxiWIi1np0z3/RDnoVyfmfbbL1DY7zf2hYXLLzsJR mSsED/1nlJ9Oq5fALdNEPgDyPUerqHxcmIub+pF0AzJoYHK5punqpqfGmqPbjxrJLPJfHVKy goMj5DlBMoYqEgpbwdUYkH6QdizJJCur4icy8GUNbisFYABeoJ91pnD4IGei3MTdvINSZI5e Message-ID: <88f94070-cd34-7435-9175-e0518a7d7db8@acm.org> Date: Thu, 9 Apr 2020 19:52:59 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <20200409214530.2413-3-mcgrof@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020-04-09 14:45, Luis Chamberlain wrote: > +void blk_q_debugfs_register(struct request_queue *q) > +{ > + q->debugfs_dir = debugfs_create_dir(kobject_name(q->kobj.parent), > + blk_debugfs_root); > +} > + > +void blk_q_debugfs_unregister(struct request_queue *q) > +{ > + debugfs_remove_recursive(q->debugfs_dir); > + q->debugfs_dir = NULL; > +} There are no other functions in the block layer that start with the prefix blk_q_. How about changing that prefix into blk_? > -#ifdef CONFIG_BLK_DEBUG_FS > +#ifdef CONFIG_DEBUG_FS > struct dentry *debugfs_dir; > +#endif Please add a comment above 'debugfs_dir' that it is used not only by the code in block/blk-*debugfs.c but also by the code in kernel/trace/blktrace.c. Otherwise this patch looks good to me. Thanks, Bart.