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| author | Muchun Song <songmuchun@bytedance.com> | 2022-03-22 14:42:05 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-03-22 15:57:04 -0700 |
| commit | 19b482c29b6f3805f1d8e93015847b89e2f7f3b1 (patch) | |
| tree | 1b01d19326fd6fbac3e85a63163563a7b23ffb6e /mm/shmem.c | |
| parent | 348923665a0e50ad9fc0b3bb8127d3cb976691cc (diff) | |
| download | linux-19b482c29b6f3805f1d8e93015847b89e2f7f3b1.tar.gz linux-19b482c29b6f3805f1d8e93015847b89e2f7f3b1.tar.bz2 linux-19b482c29b6f3805f1d8e93015847b89e2f7f3b1.zip | |
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@bytedance.com
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@bytedance.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Fam Zheng <fam.zheng@bytedance.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lars Persson <lars.persson@axis.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/shmem.c')
| -rw-r--r-- | mm/shmem.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/mm/shmem.c b/mm/shmem.c index f21eb0ef8ae0..01fd227b6947 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -2364,8 +2364,10 @@ int shmem_mfill_atomic_pte(struct mm_struct *dst_mm, /* 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; |