From: Cong Wang <xiyou.wangcong@gmail.com>
To: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH] mm: hugetlbfs: Close race during teardown of hugetlbfs shared page tables
Date: Thu, 19 Jul 2012 09:08:34 +0000 (UTC) [thread overview]
Message-ID: <ju8iqh$vvl$1@dough.gmane.org> (raw)
In-Reply-To: <20120718104220.GR9222@suse.de>
On Wed, 18 Jul 2012 at 10:43 GMT, Mel Gorman <mgorman@suse.de> wrote:
> + if (!down_read_trylock(&svma->vm_mm->mmap_sem)) {
> + mutex_unlock(&mapping->i_mmap_mutex);
> + goto retry;
> + }
> +
> + smmap_sem = &svma->vm_mm->mmap_sem;
> + spage_table_lock = &svma->vm_mm->page_table_lock;
> + spin_lock_nested(spage_table_lock, SINGLE_DEPTH_NESTING);
>
> saddr = page_table_shareable(svma, vma, addr, idx);
> if (saddr) {
> @@ -85,6 +108,10 @@ static void huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
> break;
> }
> }
> + up_read(smmap_sem);
> + spin_unlock(spage_table_lock);
Looks like we should do spin_unlock() before up_read(),
in the reverse order of how they get accquired.
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next prev parent reply other threads:[~2012-07-19 9:08 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-18 10:43 Mel Gorman
2012-07-19 9:08 ` Cong Wang [this message]
2012-07-20 13:43 ` Mel Gorman
2012-07-19 12:38 ` Hugh Dickins
2012-07-19 14:16 ` Mel Gorman
2012-07-19 14:42 ` Michal Hocko
2012-07-19 14:49 ` Mel Gorman
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