Re: [RFC PATCH] mm: hugetlbfs: Close race during teardown of hugetlbfs shared page tables
From: Cong Wang <hidden>
Date: 2012-07-19 09:08:51
On Wed, 18 Jul 2012 at 10:43 GMT, Mel Gorman [off-list ref] wrote:
quoted hunk ↗ jump to hunk
+ 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. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>