Subject: [merged] mm-fix-potential-null-pointer-dereference.patch removed from 
-mm tree
To: 
huawei.li...@huawei.com,kirill.shute...@linux.intel.com,liw...@linux.vnet.ibm.com,mho...@suse.cz,stable@vger.kernel.org,mm-comm...@vger.kernel.org
From: a...@linux-foundation.org
Date: Thu, 12 Sep 2013 12:42:53 -0700


The patch titled
     Subject: mm/huge_memory.c: fix potential NULL pointer dereference
has been removed from the -mm tree.  Its filename was
     mm-fix-potential-null-pointer-dereference.patch

This patch was dropped because it was merged into mainline or a subsystem tree

------------------------------------------------------
From: Libin <huawei.li...@huawei.com>
Subject: mm/huge_memory.c: fix potential NULL pointer dereference

In collapse_huge_page() there is a race window between releasing the
mmap_sem read lock and taking the mmap_sem write lock, so find_vma() may
return NULL.  So check the return value to avoid NULL pointer dereference.

collapse_huge_page
        khugepaged_alloc_page
                up_read(&mm->mmap_sem)
        down_write(&mm->mmap_sem)
        vma = find_vma(mm, address)

Signed-off-by: Libin <huawei.li...@huawei.com>
Acked-by: Kirill A. Shutemov <kirill.shute...@linux.intel.com>
Reviewed-by: Wanpeng Li <liw...@linux.vnet.ibm.com>
Reviewed-by: Michal Hocko <mho...@suse.cz>
Cc: <stable@vger.kernel.org> # v3.0+
Signed-off-by: Andrew Morton <a...@linux-foundation.org>
---

 mm/huge_memory.c |    2 ++
 1 file changed, 2 insertions(+)

diff -puN mm/huge_memory.c~mm-fix-potential-null-pointer-dereference 
mm/huge_memory.c
--- a/mm/huge_memory.c~mm-fix-potential-null-pointer-dereference
+++ a/mm/huge_memory.c
@@ -2296,6 +2296,8 @@ static void collapse_huge_page(struct mm
                goto out;
 
        vma = find_vma(mm, address);
+       if (!vma)
+               goto out;
        hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK;
        hend = vma->vm_end & HPAGE_PMD_MASK;
        if (address < hstart || address + HPAGE_PMD_SIZE > hend)
_

Patches currently in -mm which might be from huawei.li...@huawei.com are

origin.patch

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