This is a note to let you know that I've just added the patch titled
mm/rmap: fix potential pte_unmap on an not mapped pte
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mm-rmap-fix-potential-pte_unmap-on-an-not-mapped-pte.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 6110c0d2980cd7be6035ca4e00684f82073f87b6
Author: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Date: Thu Feb 25 17:18:09 2021 -0800
mm/rmap: fix potential pte_unmap on an not mapped pte
[ Upstream commit 5d5d19eda6b0ee790af89c45e3f678345be6f50f ]
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@xxxxxxxxxx
Fixes: ace71a19cec5 ("mm: introduce page_vma_mapped_walk()")
Signed-off-by: Hongxiang Lou <louhongxiang@xxxxxxxxxx>
Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Tested-by: Sedat Dilek <sedat.dilek@xxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Nathan Chancellor <natechancellor@xxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Shakeel Butt <shakeelb@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Michel Lespinasse <walken@xxxxxxxxxx>
Cc: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Wei Yang <richard.weiyang@xxxxxxxxxxxxxxxxx>
Cc: Dmitry Safonov <0x7f454c46@xxxxxxxxx>
Cc: Brian Geffon <bgeffon@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index 70085ca1a3fc9..def5c62c93b3b 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);
