From: Anton Vorontsov <anton@enomsg.org>
To: Hugh Dickins <hughd@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Michal Hocko <mhocko@suse.cz>,
David Rientjes <rientjes@google.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH] vmpressure: fix divide-by-0 in vmpressure_work_fn
Date: Tue, 10 Sep 2013 22:32:48 -0700 [thread overview]
Message-ID: <20130911053248.GA9064@lizard> (raw)
In-Reply-To: <alpine.LNX.2.00.1309062254470.11420@eggly.anvils>
On Fri, Sep 06, 2013 at 10:59:16PM -0700, Hugh Dickins wrote:
> Hit divide-by-0 in vmpressure_work_fn(): checking vmpr->scanned before
> taking the lock is not enough, we must check scanned afterwards too.
>
> Signed-off-by: Hugh Dickins <hughd@google.com>
> Cc: stable@vger.kernel.org
Hm... Just trying to understand this one. I don't see how this can happen,
considering that only one instance of vmpressure_work_fn() supposed to be
running (unlike vmpressure()), and the only place where we zero
vmpr->scanned is vmpressure_work_fn() itself?
> ---
>
> mm/vmpressure.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> --- 3.11/mm/vmpressure.c 2013-09-02 13:46:10.000000000 -0700
> +++ linux/mm/vmpressure.c 2013-09-06 22:43:03.596003080 -0700
> @@ -187,6 +187,9 @@ static void vmpressure_work_fn(struct wo
> vmpr->reclaimed = 0;
> spin_unlock(&vmpr->sr_lock);
>
> + if (!scanned)
> + return;
> +
> do {
> if (vmpressure_event(vmpr, scanned, reclaimed))
> break;
--
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WARNING: multiple messages have this Message-ID (diff)
From: Anton Vorontsov <anton@enomsg.org>
To: Hugh Dickins <hughd@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Michal Hocko <mhocko@suse.cz>,
David Rientjes <rientjes@google.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH] vmpressure: fix divide-by-0 in vmpressure_work_fn
Date: Tue, 10 Sep 2013 22:32:48 -0700 [thread overview]
Message-ID: <20130911053248.GA9064@lizard> (raw)
In-Reply-To: <alpine.LNX.2.00.1309062254470.11420@eggly.anvils>
On Fri, Sep 06, 2013 at 10:59:16PM -0700, Hugh Dickins wrote:
> Hit divide-by-0 in vmpressure_work_fn(): checking vmpr->scanned before
> taking the lock is not enough, we must check scanned afterwards too.
>
> Signed-off-by: Hugh Dickins <hughd@google.com>
> Cc: stable@vger.kernel.org
Hm... Just trying to understand this one. I don't see how this can happen,
considering that only one instance of vmpressure_work_fn() supposed to be
running (unlike vmpressure()), and the only place where we zero
vmpr->scanned is vmpressure_work_fn() itself?
> ---
>
> mm/vmpressure.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> --- 3.11/mm/vmpressure.c 2013-09-02 13:46:10.000000000 -0700
> +++ linux/mm/vmpressure.c 2013-09-06 22:43:03.596003080 -0700
> @@ -187,6 +187,9 @@ static void vmpressure_work_fn(struct wo
> vmpr->reclaimed = 0;
> spin_unlock(&vmpr->sr_lock);
>
> + if (!scanned)
> + return;
> +
> do {
> if (vmpressure_event(vmpr, scanned, reclaimed))
> break;
next prev parent reply other threads:[~2013-09-11 5:37 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-07 5:59 [PATCH] vmpressure: fix divide-by-0 in vmpressure_work_fn Hugh Dickins
2013-09-07 5:59 ` Hugh Dickins
2013-09-08 1:43 ` David Rientjes
2013-09-08 1:43 ` David Rientjes
2013-09-09 11:08 ` Michal Hocko
2013-09-09 11:08 ` Michal Hocko
2013-09-11 15:40 ` Anton Vorontsov
2013-09-11 15:40 ` Anton Vorontsov
2013-09-11 16:03 ` Michal Hocko
2013-09-11 16:03 ` Michal Hocko
2013-09-11 16:12 ` Anton Vorontsov
2013-09-11 16:12 ` Anton Vorontsov
2013-09-11 20:04 ` Hugh Dickins
2013-09-11 20:04 ` Hugh Dickins
2013-09-12 11:46 ` Michal Hocko
2013-09-12 11:46 ` Michal Hocko
2013-09-11 5:32 ` Anton Vorontsov [this message]
2013-09-11 5:32 ` Anton Vorontsov
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