diff options
| author | Libin <huawei.libin@huawei.com> | 2013-09-11 14:20:38 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-09-11 15:57:19 -0700 |
| commit | a8f531ebc33052642b4bd7b812eedf397108ce64 (patch) | |
| tree | eed956b9a3e7efa02937d984ae3f8d94810a478d /mm/huge_memory.c | |
| parent | e2d0bd2b924d74d5e0d4f395f8f4730d125e198c (diff) | |
| download | lwn-a8f531ebc33052642b4bd7b812eedf397108ce64.tar.gz lwn-a8f531ebc33052642b4bd7b812eedf397108ce64.zip | |
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.libin@huawei.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: <stable@vger.kernel.org> # v3.0+
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/huge_memory.c')
| -rw-r--r-- | mm/huge_memory.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 8b7fc2025e04..963e14c0486f 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2296,6 +2296,8 @@ static void collapse_huge_page(struct mm_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) |