From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
To: Vladislav Bolkhovitin <vst@vlnb.net>
Cc: Boaz Harrosh <bharrosh@panasas.com>, Greg KH <greg@kroah.com>,
linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org,
scst-devel <scst-devel@lists.sourceforge.net>,
James Bottomley <James.Bottomley@HansenPartnership.com>,
Andrew Morton <akpm@linux-foundation.org>,
FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>,
Mike Christie <michaelc@cs.wisc.edu>,
Vu Pham <vuhuong@mellanox.com>,
Bart Van Assche <bart.vanassche@gmail.com>,
James Smart <James.Smart@Emulex.Com>,
Joe Eykholt <jeykholt@cisco.com>, Andy Yan <ayan@marvell.com>,
Chetan Loke <generationgnu@yahoo.com>,
Hannes Reinecke <hare@suse.de>,
Richard Sharpe <realrichardsharpe@gmail.com>,
Daniel Henrique Debonzi <debonzi@linux.vnet.ibm.com>
Subject: Re: [PATCH 8/19]: SCST SYSFS interface implementation
Date: Mon, 15 Nov 2010 13:14:30 -0800 [thread overview]
Message-ID: <20101115211430.GA19071@core.coreip.homeip.net> (raw)
In-Reply-To: <4CE19A08.8050606@vlnb.net>
On Mon, Nov 15, 2010 at 11:37:28PM +0300, Vladislav Bolkhovitin wrote:
> Dmitry Torokhov, on 11/15/2010 10:04 AM wrote:
>
> >> This is because SYSFS doesn't hold references for the corresponding
> >> kobjects for every open file handle. It holds references only when
> >> show() and store() functions called. So, everything is under control and
> >> a malicious user can do nothing to hold a reference forever.
> >
> > Right, Tejun plugged this particular (and very annoying) attributes
> > behavior
>
> This behavior isn't annoying, it's GREAT, because it allows to use SYSFS
> simply and reliably.
Right, I mean that _before_ Tejun plugged that hole the behavior _was_
annoying.
>
> >, but that does not mean that this is the only way kobject's
> > reference might be pinned.
>
> Could you be more specific and point out on exact ways for that? From my
> quite deep SYSFS source code study I see such cases should not exist.
While I do not know offhand I am sure there are such scenarios. Isn't
there any way for the users that you are waiting on descend back into
your module that is waiting for kobject removal and get stuck on some
resource?
Even if it isn't possible now the scheme is quite fragile. Kobjects are
refcounted so work with them appropriately (rely on refcount, do not
wait, etc).
--
Dmitry
next prev parent reply other threads:[~2010-11-15 21:14 UTC|newest]
Thread overview: 93+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-01 21:34 [PATCHv4 0/19]: New SCSI target framework (SCST) with dev handlers and 2 target drivers Vladislav Bolkhovitin
2010-10-01 21:36 ` [PATCH 1/19]: Integration of SCST into the Linux kernel tree Vladislav Bolkhovitin
2010-10-01 21:36 ` [PATCH 2/19]: SCST core's Makefile and Kconfig Vladislav Bolkhovitin
2010-10-01 21:38 ` [PATCH 3/19]: SCST public headers Vladislav Bolkhovitin
2010-10-01 21:39 ` [PATCH 4/19]: SCST main management files and private headers Vladislav Bolkhovitin
2010-10-01 21:42 ` [PATCH 5/19]: SCST implementation of the SCSI target state machine Vladislav Bolkhovitin
2010-10-01 21:43 ` [PATCH 6/19]: SCST internal library functions Vladislav Bolkhovitin
2010-10-01 21:44 ` [PATCH 7/19]: SCST Persistent Reservations implementation Vladislav Bolkhovitin
2010-10-01 21:46 ` [PATCH 8/19]: SCST SYSFS interface implementation Vladislav Bolkhovitin
2010-10-09 21:20 ` Greg KH
2010-10-11 19:29 ` Vladislav Bolkhovitin
2010-10-11 21:32 ` Greg KH
2010-10-12 18:53 ` Vladislav Bolkhovitin
2010-10-12 19:03 ` Greg KH
2010-10-14 19:48 ` Vladislav Bolkhovitin
2010-10-14 20:04 ` Greg KH
2010-10-22 17:30 ` Vladislav Bolkhovitin
2010-10-22 17:56 ` Greg KH
2010-10-22 18:40 ` Vladislav Bolkhovitin
2010-10-22 18:54 ` Greg KH
2010-11-08 19:58 ` Vladislav Bolkhovitin
2010-11-09 0:28 ` Greg KH
2010-11-09 20:06 ` Vladislav Bolkhovitin
2010-11-10 9:58 ` Boaz Harrosh
2010-11-10 20:19 ` Vladislav Bolkhovitin
2010-11-10 20:29 ` Joe Eykholt
2010-11-10 20:38 ` Vladislav Bolkhovitin
2010-11-10 20:42 ` Joe Eykholt
2010-11-11 9:59 ` Boaz Harrosh
2010-11-11 12:04 ` Greg KH
2010-11-11 14:05 ` Boaz Harrosh
2010-11-11 14:16 ` Greg KH
2010-11-11 14:19 ` Boaz Harrosh
2010-11-11 20:50 ` Vladislav Bolkhovitin
2010-11-12 1:23 ` Dmitry Torokhov
2010-11-12 12:09 ` Bart Van Assche
2010-11-12 18:44 ` Dmitry Torokhov
2010-11-13 10:52 ` Bart Van Assche
2010-11-13 17:20 ` Vladislav Bolkhovitin
2010-11-13 23:59 ` Greg KH
2010-11-15 6:59 ` Dmitry Torokhov
2010-11-15 17:53 ` Bart Van Assche
2010-11-15 20:36 ` Vladislav Bolkhovitin
2010-11-15 9:46 ` Boaz Harrosh
2010-11-15 16:16 ` Greg KH
2010-11-15 17:19 ` Boaz Harrosh
2010-11-15 17:49 ` Bart Van Assche
2010-11-15 20:19 ` Nicholas A. Bellinger
2010-11-16 13:12 ` Vladislav Bolkhovitin
2010-11-16 11:59 ` [Scst-devel] " Richard Williams
2010-11-16 13:17 ` Vladislav Bolkhovitin
2010-11-18 21:02 ` Vladislav Bolkhovitin
2010-11-18 21:46 ` Greg KH
2010-11-19 18:00 ` Vladislav Bolkhovitin
2010-11-19 20:22 ` Dmitry Torokhov
2010-11-19 20:50 ` Vladislav Bolkhovitin
2010-11-19 21:16 ` Greg KH
2010-11-24 20:35 ` Vladislav Bolkhovitin
2010-11-19 21:19 ` Greg KH
2010-12-10 12:06 ` Bart Van Assche
2010-12-10 19:36 ` Greg KH
2010-12-14 14:10 ` Bart Van Assche
2010-11-19 18:01 ` Bart Van Assche
2010-11-15 20:39 ` Vladislav Bolkhovitin
2010-11-15 20:39 ` Vladislav Bolkhovitin
2010-11-15 17:45 ` Bart Van Assche
2010-11-15 18:44 ` Greg KH
2010-11-15 20:39 ` Vladislav Bolkhovitin
2010-11-15 22:13 ` Greg KH
2010-11-16 5:04 ` Joe Eykholt
2010-11-16 6:03 ` Nicholas A. Bellinger
2010-11-16 8:49 ` Florian Mickler
2010-11-16 13:18 ` Vladislav Bolkhovitin
2010-11-16 7:15 ` Bart Van Assche
2010-11-16 13:19 ` Vladislav Bolkhovitin
2010-11-15 20:36 ` Vladislav Bolkhovitin
2010-11-15 7:04 ` Dmitry Torokhov
2010-11-15 20:37 ` Vladislav Bolkhovitin
2010-11-15 21:14 ` Dmitry Torokhov [this message]
2010-11-16 13:13 ` Vladislav Bolkhovitin
2010-10-01 21:46 ` [PATCH 9/19]: SCST debugging support routines Vladislav Bolkhovitin
2010-10-01 21:48 ` [PATCH 10/19]: SCST SGV cache Vladislav Bolkhovitin
2010-10-01 21:48 ` [PATCH 11/19]: SCST core's docs Vladislav Bolkhovitin
2010-10-01 21:49 ` [PATCH 12/19]: SCST dev handlers' Makefile Vladislav Bolkhovitin
2010-10-01 21:50 ` [PATCH 13/19]: SCST vdisk dev handler Vladislav Bolkhovitin
2010-10-01 21:51 ` [PATCH 14/19]: SCST pass-through dev handlers Vladislav Bolkhovitin
2010-10-01 21:53 ` [PATCH 15/19]: Implementation of blk_rq_map_kern_sg() Vladislav Bolkhovitin
2010-10-01 21:57 ` [PATCH 16/19]: scst_local target driver Vladislav Bolkhovitin
2010-10-01 21:58 ` [PATCH 17/19]: SCST InfiniBand SRP " Vladislav Bolkhovitin
2010-10-01 22:04 ` [PATCH 18/19]: ibmvstgt: Port from tgt to SCST Vladislav Bolkhovitin
2010-10-01 22:05 ` [PATCH 19/19]: tgt: Removal Vladislav Bolkhovitin
2010-10-02 7:40 ` [PATCHv4 0/19]: New SCSI target framework (SCST) with dev handlers and 2 target drivers Bart Van Assche
2010-10-06 20:21 ` [Scst-devel] " Steve Modica
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