linux-kernel - Re: [PATCH] fs: allow d_instantiate to be called with negative parent dentry

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-Id: <1246283143.754.16.camel@dhcp235-23.rdu.redhat.com>
Date:	Mon, 29 Jun 2009 09:45:43 -0400
From:	Eric Paris <eparis@...hat.com>
To:	Jeremy Kerr <jk@...abs.org>
Cc:	linux-kernel@...r.kernel.org,
	Andrew Morton <akpm@...ux-foundation.org>,
	Christoph Hellwig <hch@....de>, cbe-oss-dev@...abs.org
Subject: Re: [PATCH] fs: allow d_instantiate to be called with negative
 parent dentry

On Mon, 2009-06-29 at 14:31 +0800, Jeremy Kerr wrote:
> The new fsnotify infrastructure (starting at 90586523) causes an oops in
> spufs, where we populate a directory with files before instantiating the
> directory itself. The new changes seem to have introduced an assumption
> that a dentry's parent will be positive when instantiating.
> 
> This change makes it once again possible to d_instantiate a dentry
> with a negative parent, and brings __fsnotify_d_instantiate() into
> line with inotify_d_instantiate(), which already has this NULL check.
> 
> Signed-off-by: Jeremy Kerr <jk@...abs.org>

This problem was introduced based on a private off list comment from Al
Viro back on Feb 17th when he was reviewing my code:

fsnotify_d_instantiate(): check for NULL inode in parent?  Really?
BTW, where's the codepath without that stuff?  I mean, for sane
boxen that have *notify configured out.  Idiotify is at least
configurable away...

>>From that comment I dropped the check for dentry->d_parent->d_inode.
The old behavior (which inotify had) is exactly what you propose and
would cause no problems for anything.  I'll leave it up to Al if he
wants to argue that the spufs logic is illegal but I'll put this patch
into my tree and send it toward Linus.

-Eric

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/