The patch titled
Subject: mm: shmem: fix missing cache flush in shmem_mfill_atomic_pte()
has been removed from the -mm tree. Its filename was
mm-shmem-fix-missing-cache-flush-in-shmem_mfill_atomic_pte.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Subject: mm: shmem: fix missing cache flush in shmem_mfill_atomic_pte()
userfaultfd calls shmem_mfill_atomic_pte() which does not do any cache
flushing for the target page. Then the target page will be mapped to the
user space with a different address (user address), which might have an
alias issue with the kernel address used to copy the data from the user
to. Insert flush_dcache_page() in non-zero-page case. And replace
clear_highpage() with clear_user_highpage() which already considers the
cache maintenance.
Link: https://lkml.kernel.org/r/20220210123058.79206-6-songmuchun@xxxxxxxxxxxxx
Fixes: 8d1039634206 ("userfaultfd: shmem: add shmem_mfill_zeropage_pte for userfaultfd support")
Fixes: 4c27fe4c4c84 ("userfaultfd: shmem: add shmem_mcopy_atomic_pte for userfaultfd support")
Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Reviewed-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Axel Rasmussen <axelrasmussen@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Fam Zheng <fam.zheng@xxxxxxxxxxxxx>
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Lars Persson <lars.persson@xxxxxxxx>
Cc: Peter Xu <peterx@xxxxxxxxxx>
Cc: Xiongchun Duan <duanxiongchun@xxxxxxxxxxxxx>
Cc: Zi Yan <ziy@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/shmem.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/mm/shmem.c~mm-shmem-fix-missing-cache-flush-in-shmem_mfill_atomic_pte
+++ a/mm/shmem.c
@@ -2364,8 +2364,10 @@ int shmem_mfill_atomic_pte(struct mm_str
/* don't free the page */
goto out_unacct_blocks;
}
+
+ flush_dcache_page(page);
} else { /* ZEROPAGE */
- clear_highpage(page);
+ clear_user_highpage(page, dst_addr);
}
} else {
page = *pagep;
_
Patches currently in -mm which might be from songmuchun@xxxxxxxxxxxxx are
