Messages in this thread Patch in this message | | | Date | Fri, 20 Jul 2012 14:43:44 +0100 | From | Mel Gorman <> | Subject | Re: [RFC PATCH] mm: hugetlbfs: Close race during teardown of hugetlbfs shared page tables |
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On Thu, Jul 19, 2012 at 09:08:34AM +0000, Cong Wang wrote: > 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. >
Will fix, thanks for pointing this out.
As an aside, I would prefer if you did not drop people from the CC list. I would have missed this mail for a long time if it hadn't been pointed out to me privately.
-- Mel Gorman SUSE Labs
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