From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <SRS0=4nbc=R5=vger.kernel.org=linux-kernel-owner@kernel.org>
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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,
	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 63534C43381
	for <linux-kernel@archiver.kernel.org>; Tue, 26 Mar 2019 01:45:59 +0000 (UTC)
Received: from vger.kernel.org (vger.kernel.org [209.132.180.67])
	by mail.kernel.org (Postfix) with ESMTP id 29A9A206DF
	for <linux-kernel@archiver.kernel.org>; Tue, 26 Mar 2019 01:45:59 +0000 (UTC)
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1730657AbfCZBp6 (ORCPT
        <rfc822;linux-kernel@archiver.kernel.org>);
        Mon, 25 Mar 2019 21:45:58 -0400
Received: from zeniv.linux.org.uk ([195.92.253.2]:58730 "EHLO
        ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S1727412AbfCZBp5 (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Mon, 25 Mar 2019 21:45:57 -0400
Received: from viro by ZenIV.linux.org.uk with local (Exim 4.92 #3 (Red Hat Linux))
        id 1h8bA1-0004h2-21; Tue, 26 Mar 2019 01:45:53 +0000
Date:   Tue, 26 Mar 2019 01:45:53 +0000
From:   Al Viro <viro@zeniv.linux.org.uk>
To:     Linus Torvalds <torvalds@linux-foundation.org>
Cc:     syzbot <syzbot+7a8ba368b47fdefca61e@syzkaller.appspotmail.com>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>,
        Linux List Kernel Mailing <linux-kernel@vger.kernel.org>,
        syzkaller-bugs <syzkaller-bugs@googlegroups.com>
Subject: Re: KASAN: use-after-free Read in path_lookupat
Message-ID: <20190326014552.GY2217@ZenIV.linux.org.uk>
References: <0000000000006946d2057bbd0eef@google.com>
 <CAHk-=wiijJMTw=nTj_ED+YWMCrvHzh3ezfVYRxvzcW6+trgyPA@mail.gmail.com>
 <20190325045744.GK2217@ZenIV.linux.org.uk>
 <CAHk-=wg4iJsMHBzK52WzP+5_92HbwvX_vh_s4mMUuN0FJGdM5A@mail.gmail.com>
 <CAHk-=whJ4M5FegOLvnjUtJ0+pHv4L8UNFt+9jJDhox3Ada8kwA@mail.gmail.com>
 <20190325211405.GP2217@ZenIV.linux.org.uk>
 <CAHk-=wj+-e=X9cvvNwc5+QuvBOyYT7OtZTBzy-Wg8zGrUwxSbw@mail.gmail.com>
 <20190325233731.GS2217@ZenIV.linux.org.uk>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20190325233731.GS2217@ZenIV.linux.org.uk>
User-Agent: Mutt/1.10.1 (2018-07-13)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Mon, Mar 25, 2019 at 11:37:32PM +0000, Al Viro wrote:

> For debugfs it's clearly "use default ->evict_inode(), have explicit
> ->destroy_inode() using free_inode_nonrcu()" - there we have nothing
> else done in ->evict_inode() and kfree is obviously safe in softirq.
> I'll post that (or push to vfs.git#fixes), along with minimal fixes
> for other 3.  If bpf_any_put() is softirq-safe, we'll have the full
> set for -stable and the rest could be done on top of that.
> 
> Won't solve the documetation problem, unfortunately ;-/

Posted; all of those (as well as Daniel's bpf patch) are Cc:stable
fodder.  Documentation is still, er, deficient...