From: Andrew Morton <akpm@linux-foundation.org>
To: Weijie Yang <weijie.yang@samsung.com>
Cc: hughd@google.com, 'Minchan Kim' <minchan@kernel.org>,
shli@kernel.org, 'Bob Liu' <bob.liu@oracle.com>,
weijie.yang.kh@gmail.com,
'Seth Jennings' <sjennings@variantweb.net>,
'Heesub Shin' <heesub.shin@samsung.com>,
mquzik@redhat.com, 'Linux-MM' <linux-mm@kvack.org>,
'linux-kernel' <linux-kernel@vger.kernel.org>,
stable@vger.kernel.org
Subject: Re: [PATCH 2/8] mm/swap: fix race on swap_info reuse between swapoff and swapon
Date: Mon, 3 Feb 2014 15:23:40 -0800 [thread overview]
Message-ID: <20140203152340.b28bb35698ee75615eb23041@linux-foundation.org> (raw)
In-Reply-To: <000d01cf1b47$f12e11f0$d38a35d0$%yang@samsung.com>
On Mon, 27 Jan 2014 18:03:04 +0800 Weijie Yang <weijie.yang@samsung.com> wrote:
> swapoff clear swap_info's SWP_USED flag prematurely and free its resources
> after that. A concurrent swapon will reuse this swap_info while its previous
> resources are not cleared completely.
>
> These late freed resources are:
> - p->percpu_cluster
> - swap_cgroup_ctrl[type]
> - block_device setting
> - inode->i_flags &= ~S_SWAPFILE
>
> This patch clear SWP_USED flag after all its resources freed, so that swapon
> can reuse this swap_info by alloc_swap_info() safely.
>
> This patch is just for a rare scenario, aim to correct of code.
I believe that
http://ozlabs.org/~akpm/mmots/broken-out/mm-swap-fix-race-on-swap_info-reuse-between-swapoff-and-swapon.patch
makes this patch redundant?
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WARNING: multiple messages have this Message-ID (diff)
From: Andrew Morton <akpm@linux-foundation.org>
To: Weijie Yang <weijie.yang@samsung.com>
Cc: hughd@google.com, "'Minchan Kim'" <minchan@kernel.org>,
shli@kernel.org, "'Bob Liu'" <bob.liu@oracle.com>,
weijie.yang.kh@gmail.com,
"'Seth Jennings'" <sjennings@variantweb.net>,
"'Heesub Shin'" <heesub.shin@samsung.com>,
mquzik@redhat.com, "'Linux-MM'" <linux-mm@kvack.org>,
"'linux-kernel'" <linux-kernel@vger.kernel.org>,
stable@vger.kernel.org
Subject: Re: [PATCH 2/8] mm/swap: fix race on swap_info reuse between swapoff and swapon
Date: Mon, 3 Feb 2014 15:23:40 -0800 [thread overview]
Message-ID: <20140203152340.b28bb35698ee75615eb23041@linux-foundation.org> (raw)
In-Reply-To: <000d01cf1b47$f12e11f0$d38a35d0$%yang@samsung.com>
On Mon, 27 Jan 2014 18:03:04 +0800 Weijie Yang <weijie.yang@samsung.com> wrote:
> swapoff clear swap_info's SWP_USED flag prematurely and free its resources
> after that. A concurrent swapon will reuse this swap_info while its previous
> resources are not cleared completely.
>
> These late freed resources are:
> - p->percpu_cluster
> - swap_cgroup_ctrl[type]
> - block_device setting
> - inode->i_flags &= ~S_SWAPFILE
>
> This patch clear SWP_USED flag after all its resources freed, so that swapon
> can reuse this swap_info by alloc_swap_info() safely.
>
> This patch is just for a rare scenario, aim to correct of code.
I believe that
http://ozlabs.org/~akpm/mmots/broken-out/mm-swap-fix-race-on-swap_info-reuse-between-swapoff-and-swapon.patch
makes this patch redundant?
next prev parent reply other threads:[~2014-02-03 23:23 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-27 10:03 [PATCH 2/8] mm/swap: fix race on swap_info reuse between swapoff and swapon Weijie Yang
2014-01-27 10:03 ` Weijie Yang
2014-02-03 23:23 ` Andrew Morton [this message]
2014-02-03 23:23 ` Andrew Morton
2014-02-03 23:29 ` Andrew Morton
2014-02-03 23:29 ` Andrew Morton
2014-02-04 4:14 ` Hugh Dickins
2014-02-04 4:14 ` Hugh Dickins
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