From: Al Viro <viro@ZenIV.linux.org.uk>
To: NeilBrown <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 02:04:59 +0000 [thread overview]
Message-ID: <20080114020459.GN27894@ZenIV.linux.org.uk> (raw)
In-Reply-To: <1080114014531.20354@suse.de>
On Mon, Jan 14, 2008 at 12:45:31PM +1100, NeilBrown wrote:
>
> Due to possible deadlock issues we need to use a schedule work to
> kobject_del an 'rdev' object from a different thread.
>
> A recent change means that kobject_add no longer gets a refernce, and
> kobject_del doesn't put a reference. Consequently, we need to
> explicitly hold a reference to ensure that the last reference isn't
> dropped before the scheduled work get a chance to call kobject_del.
>
> Also, rename delayed_delete to md_delayed_delete to that it is more
> obvious in a stack trace which code is to blame.
I don't know... You still get kobject_del() and export_rdev()
in unpredictable order; sure, it won't be freed under you, but...
What is that deadlock problem, anyway? I don't see anything that
would look like an obvious candidate in the stuff you are delaying...
next prev parent reply other threads:[~2008-01-14 2:04 UTC|newest]
Thread overview: 23+ 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 ` NeilBrown
2008-01-14 1:45 ` [PATCH 001 of 6] md: Fix an occasional deadlock in raid5 NeilBrown
2008-01-14 1:45 ` 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 1:45 ` NeilBrown
2008-01-14 2:04 ` Al Viro [this message]
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
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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