From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752021AbeENCrb (ORCPT ); Sun, 13 May 2018 22:47:31 -0400 Received: from zeniv.linux.org.uk ([195.92.253.2]:45776 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751219AbeENCra (ORCPT ); Sun, 13 May 2018 22:47:30 -0400 Date: Mon, 14 May 2018 03:47:27 +0100 From: Al Viro To: Tetsuo Handa Cc: syzbot , linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, gregkh@linuxfoundation.org, tj@kernel.org Subject: Re: general protection fault in kernfs_kill_sb (2) Message-ID: <20180514024726.GB30522@ZenIV.linux.org.uk> References: <0000000000008fa9d3056c053291@google.com> <14892403-d680-dc5d-1927-bc4a279514fb@I-love.SAKURA.ne.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <14892403-d680-dc5d-1927-bc4a279514fb@I-love.SAKURA.ne.jp> User-Agent: Mutt/1.9.1 (2017-09-22) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, May 13, 2018 at 11:19:46AM +0900, Tetsuo Handa wrote: > This is what I reported at > https://groups.google.com/d/msg/syzkaller-bugs/ISOJlV2I2QM/qHslGMi3AwAJ . > > We are currently waiting for comments from Al Viro. 1) the damn thing is unusable without javashit. Which gets about the same reaction as sending something.doc in attachment. Please, find a less obnoxious way to archive the thing (or to generate URLs that would work without that garbage). 2) deactivate_locked_super() *WILL* be called when fill_super() fails. Live with it; it allows to simplify a whole lot of cleanup logics in various filesystems. Again, we are not going for a model where ->kill_sb() is not called for something returned by sget(). Rationale: rarely exercised paths tend to rot, so anything that increases the duplication of bits and pieces of normal teardown into failure exits of foo_fill_super() is a bloody bad idea. If anything, we want to take a lot of stuff out of ->put_super() instances directly into ->kill_sb() ones, precisely because ->put_super() is only called for fully set up filesystems. 3) kernfs needs to be fixed. The rest of the dropped commits were made redundant by 8e04944f0ea8; this one wasn't. Mea culpa.