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From: Al Viro <viro@ZenIV.linux.org.uk>
To: Neil Brown <neilb@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 002 of 6] md: Fix use-after-free bug when dropping an rdev from an md array.
Date: Mon, 14 Jan 2008 13:56:18 +0000	[thread overview]
Message-ID: <20080114135618.GQ27894@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20080114125939.GP27894@ZenIV.linux.org.uk>

On Mon, Jan 14, 2008 at 12:59:39PM +0000, Al Viro wrote:

> I really don't like the entire scheme, to be honest.  BTW, what happens
> if you try to add the same device to the same array after having it kicked
> out?  If that comes before your delayed kobject_del(), the things will
> get nasty since sysfs will (rightfully) refuse to add another entry with
> the same name and parent while the old one is still there and for all
> sysfs knows is going to stay there...

More fun questions: what are the locking requirements for ->resize()?
You are calling it with no exclusion whatsoever...  What about
bind_rdev_to_array()?  At the very least, you want to protect
mddev->disks, and AFAICS new_dev_store() has no exclusion at all.
And I suspect that you have other things in there in need of protection
(finding free desc_nr, for one); can all of those be handled by simple
spinlocks?

  reply	other threads:[~2008-01-14 13:56 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-01-14  1:45 [PATCH 000 of 6] md: various fixes for md NeilBrown
2008-01-14  1:45 ` [PATCH 001 of 6] md: Fix an occasional deadlock in raid5 NeilBrown
2008-01-16  5:01   ` dean gaudet
2008-01-16  5:54     ` Andrew Morton
2008-01-16  6:13       ` dean gaudet
2008-01-16  7:09         ` Dan Williams
2008-01-16  7:15           ` Andrew Morton
2008-01-16 21:54             ` Neil Brown
2008-01-14  1:45 ` [PATCH 002 of 6] md: Fix use-after-free bug when dropping an rdev from an md array NeilBrown
2008-01-14  2:04   ` Al Viro
2008-01-14  3:21     ` Neil Brown
2008-01-14  3:43       ` Al Viro
2008-01-14  4:48         ` Neil Brown
2008-01-14  6:28           ` Neil Brown
2008-01-14 12:59             ` Al Viro
2008-01-14 13:56               ` Al Viro [this message]
2008-01-14  1:45 ` [PATCH 003 of 6] md: Change a few 'int' to 'size_t' in md NeilBrown
2008-01-14  1:45 ` [PATCH 004 of 6] md: Change INTERATE_MDDEV to for_each_mddev NeilBrown
2008-01-14  1:45 ` [PATCH 005 of 6] md: Change ITERATE_RDEV to rdev_for_each NeilBrown
2008-01-14  1:45 ` [PATCH 006 of 6] md: Change ITERATE_RDEV_GENERIC to rdev_for_each_list, and remove ITERATE_RDEV_PENDING NeilBrown

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