linux-kernel - Re: hugetlb oops on 3.1.0-rc8-devel

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Date:	Wed, 2 Nov 2011 10:18:50 -0700
From:	Andy Lutomirski <luto@...capital.net>
To:	Hillf Danton <dhillf@...il.com>
Cc:	linux-kernel@...r.kernel.org, linux-mm@...ck.org
Subject: Re: hugetlb oops on 3.1.0-rc8-devel

On Wed, Nov 2, 2011 at 5:06 AM, Hillf Danton <dhillf@...il.com> wrote:
> On Wed, Nov 2, 2011 at 6:20 AM, Andy Lutomirski <luto@...capital.net> wrote:
>> The line that crashed is BUG_ON(page_count(old_page) != 1) in hugetlb_cow.
>>
>
> Hello Andy
>
> Would you please try the following patch?
>
> Thanks
>        Hillf
>
>
> --- a/mm/hugetlb.c      Sat Aug 13 11:45:14 2011
> +++ b/mm/hugetlb.c      Wed Nov  2 20:12:00 2011
> @@ -2422,6 +2422,8 @@ retry_avoidcopy:
>         * anon_vma prepared.
>         */
>        if (unlikely(anon_vma_prepare(vma))) {
> +               page_cache_release(new_page);
> +               page_cache_release(old_page);
>                /* Caller expects lock to be held */
>                spin_lock(&mm->page_table_lock);
>                return VM_FAULT_OOM;
>

I'll patch it in.  My test case took over a week to hit it once, so I
can't guarantee I'll spot it.

--Andy
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