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Commit 61da7969 authored by Fan Yang's avatar Fan Yang Committed by Yang Yingliang
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mm: Fix mremap not considering huge pmd devmap


mainline inclusion
from mainline-v5.7
commit 5bfea2d9
category: bugfix
bugzilla: NA
CVE: CVE-2020-10757

---------------------------

The original code in mm/mremap.c checks huge pmd by:

		if (is_swap_pmd(*old_pmd) || pmd_trans_huge(*old_pmd)) {

However, a DAX mapped nvdimm is mapped as huge page (by default) but it
is not transparent huge page (_PAGE_PSE | PAGE_DEVMAP).  This commit
changes the condition to include the case.

This addresses CVE-2020-10757.

Fixes: 5c7fb56e ("mm, dax: dax-pmd vs thp-pmd vs hugetlbfs-pmd")
Cc: <stable@vger.kernel.org>
Reported-by: default avatarFan Yang <Fan_Yang@sjtu.edu.cn>
Signed-off-by: default avatarFan Yang <Fan_Yang@sjtu.edu.cn>
Tested-by: default avatarFan Yang <Fan_Yang@sjtu.edu.cn>
Tested-by: default avatarDan Williams <dan.j.williams@intel.com>
Reviewed-by: default avatarDan Williams <dan.j.williams@intel.com>
Acked-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarYang Yingliang <yangyingliang@huawei.com>
Reviewed-by: default avatarKefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: default avatarJason Yan <yanaijie@huawei.com>
Signed-off-by: default avatarYang Yingliang <yangyingliang@huawei.com>
parent 4d7f24cf
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