diff options
| author | Muchun Song <songmuchun@bytedance.com> | 2022-03-22 14:42:08 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-03-22 15:57:04 -0700 |
| commit | 7c25a0b89a487878b0691e6524fb5a8827322194 (patch) | |
| tree | a22f9c26a0eb8ee1380026611d528a7ecd7f012c | |
| parent | 19b482c29b6f3805f1d8e93015847b89e2f7f3b1 (diff) | |
mm: userfaultfd: fix missing cache flush in mcopy_atomic_pte() and __mcopy_atomic()
userfaultfd calls mcopy_atomic_pte() and __mcopy_atomic() which do 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. Fix this by insert flush_dcache_page() after
copy_from_user() succeeds.
Link: https://lkml.kernel.org/r/20220210123058.79206-7-songmuchun@bytedance.com
Fixes: b6ebaedb4cb1 ("userfaultfd: avoid mmap_sem read recursion in mcopy_atomic")
Fixes: c1a4de99fada ("userfaultfd: mcopy_atomic|mfill_zeropage: UFFDIO_COPY|UFFDIO_ZEROPAGE preparation")
Signed-off-by: Muchun Song <songmuchun@bytedance.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: Mike Kravetz <mike.kravetz@oracle.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>
| -rw-r--r-- | mm/userfaultfd.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c index 0780c2a57ff1..6ccc534d1c1c 100644 --- a/mm/userfaultfd.c +++ b/mm/userfaultfd.c @@ -150,6 +150,8 @@ static int mcopy_atomic_pte(struct mm_struct *dst_mm, /* don't free the page */ goto out; } + + flush_dcache_page(page); } else { page = *pagep; *pagep = NULL; @@ -625,6 +627,7 @@ retry: err = -EFAULT; goto out; } + flush_dcache_page(page); goto retry; } else BUG_ON(page); |