LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
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...

  reply	other threads:[~2008-01-14  2:05 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 [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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20080114020459.GN27894@ZenIV.linux.org.uk \
    --to=viro@zeniv.linux.org.uk \
    --cc=akpm@linux-foundation.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-raid@vger.kernel.org \
    --cc=neilb@suse.de \
    --subject='Re: [PATCH 002 of 6] md: Fix use-after-free bug when dropping an rdev from an md array.' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).