From: Chris Wright <chrisw@sous-sol.org>
To: Andrea Righi <andrea@betterlinux.com>
Cc: Chris Wright <chrisw@sous-sol.org>, CAI Qian <caiqian@redhat.com>,
Hugh Dickins <hughd@google.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Rik van Riel <riel@redhat.com>, Mel Gorman <mel@csn.ul.ie>,
Izik Eidus <ieidus@redhat.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH] ksm: fix race between ksmd and exiting task
Date: Thu, 2 Jun 2011 14:23:48 -0700 [thread overview]
Message-ID: <20110602212348.GM23047@sequoia.sous-sol.org> (raw)
In-Reply-To: <20110602201236.GB4114@thinkpad>
* Andrea Righi (andrea@betterlinux.com) wrote:
> On Thu, Jun 02, 2011 at 10:35:49AM -0700, Chris Wright wrote:
> > Andrea Righi reported a case where an exiting task can race against
> > ksmd.
> >
> > ksm_scan.mm_slot == the only registered mm
> > CPU 1 (bug program) CPU 2 (ksmd)
> > list_empty() is false
> > lock
> > ksm_scan.mm_slot
> > list_del
> > unlock
> > slot == &ksm_mm_head (but list is now empty_)
> >
> > Close this race by revalidating that the new slot is not simply the list
> > head again.
>
> I confirm this fixes the problem on my side.
>
> Tested-by: Andrea Righi <andrea@betterlinux.com>
Great, thanks for verifying.
thanks,
-chris
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next prev parent reply other threads:[~2011-06-02 21:24 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-01 22:20 [BUG 3.0.0-rc1] ksm: NULL pointer dereference in ksm_do_scan() Andrea Righi
2011-06-02 1:53 ` Chris Wright
2011-06-02 7:09 ` CAI Qian
2011-06-02 14:19 ` Andrea Righi
2011-06-02 16:48 ` Chris Wright
2011-06-02 17:29 ` Hugh Dickins
2011-06-02 17:43 ` Andrea Arcangeli
2011-06-03 17:06 ` Hugh Dickins
2011-06-03 18:13 ` Andrea Arcangeli
2011-06-02 17:35 ` [PATCH] ksm: fix race between ksmd and exiting task Chris Wright
2011-06-02 20:12 ` Andrea Righi
2011-06-02 21:23 ` Chris Wright [this message]
2011-06-03 16:37 ` Hugh Dickins
2011-06-04 0:54 ` [PATCH] ksm: fix NULL pointer dereference in scan_get_next_rmap_item Chris Wright
2011-06-02 20:10 ` [BUG 3.0.0-rc1] ksm: NULL pointer dereference in ksm_do_scan() Andrea Righi
2011-06-03 4:42 ` CAI Qian
2011-06-02 14:31 ` Chris Wright
2011-06-02 14:36 ` Andrea Arcangeli
2011-06-02 15:36 ` Chris Wright
2011-06-02 16:44 ` Andrea Arcangeli
2011-06-02 20:15 ` Andrea Righi
2011-06-02 21:35 ` Andrea Arcangeli
2011-06-03 4:50 ` CAI Qian
2011-06-03 4:44 ` CAI Qian
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