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authorMiaohe Lin <linmiaohe@huawei.com>2021-02-25 17:18:09 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2021-02-26 09:41:01 -0800
commit5d5d19eda6b0ee790af89c45e3f678345be6f50f (patch)
tree1b3b59122202a33d8033113163af077a8548eab4 /include
parentad8a20cf6d19a9506b4a554030bafc1ac204ef31 (diff)
mm/rmap: fix potential pte_unmap on an not mapped pte
For PMD-mapped page (usually THP), pvmw->pte is NULL. For PTE-mapped THP, pvmw->pte is mapped. But for HugeTLB pages, pvmw->pte is not mapped and set to the relevant page table entry. So in page_vma_mapped_walk_done(), we may do pte_unmap() for HugeTLB pte which is not mapped. Fix this by checking pvmw->page against PageHuge before trying to do pte_unmap(). Link: https://lkml.kernel.org/r/20210127093349.39081-1-linmiaohe@huawei.com Fixes: ace71a19cec5 ("mm: introduce page_vma_mapped_walk()") Signed-off-by: Hongxiang Lou <louhongxiang@huawei.com> Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Cc: Kees Cook <keescook@chromium.org> Cc: Nathan Chancellor <natechancellor@gmail.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Michel Lespinasse <walken@google.com> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Wei Yang <richard.weiyang@linux.alibaba.com> Cc: Dmitry Safonov <0x7f454c46@gmail.com> Cc: Brian Geffon <bgeffon@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/rmap.h3
1 files changed, 2 insertions, 1 deletions
diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index 70085ca1a3fc..def5c62c93b3 100644
--- a/include/linux/rmap.h
+++ b/include/linux/rmap.h
@@ -213,7 +213,8 @@ struct page_vma_mapped_walk {
static inline void page_vma_mapped_walk_done(struct page_vma_mapped_walk *pvmw)
{
- if (pvmw->pte)
+ /* HugeTLB pte is set to the relevant page table entry without pte_mapped. */
+ if (pvmw->pte && !PageHuge(pvmw->page))
pte_unmap(pvmw->pte);
if (pvmw->ptl)
spin_unlock(pvmw->ptl);