RDMA/umem: Fix missing mmap_sem in get umem ODP call

Add mmap_sem lock around VMA inspection in ib_umem_odp_get().

Fixes: 0008b84ea9af ('IB/umem: Add support to huge ODP')
Signed-off-by: Artemy Kovalyov <artemyko@mellanox.com>
Reviewed-by: Eli Cohen <eli@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

1 files changed, 5 insertions, 1 deletions

diff --git a/drivers/infiniband/core/umem_odp.c b/drivers/infiniband/core/umem_odp.c
index 0780b1afefa9..8c4ec564e495 100644
--- a/drivers/infiniband/core/umem_odp.c
+++ b/drivers/infiniband/core/umem_odp.c
@@ -321,11 +321,15 @@ int ib_umem_odp_get(struct ib_ucontext *context, struct ib_umem *umem,
                 struct vm_area_struct *vma;
                 struct hstate *h;
 
+                down_read(&mm->mmap_sem);
                 vma = find_vma(mm, ib_umem_start(umem));
-                if (!vma || !is_vm_hugetlb_page(vma))
+                if (!vma || !is_vm_hugetlb_page(vma)) {
+                        up_read(&mm->mmap_sem);
                         return -EINVAL;
+                }
                 h = hstate_vma(vma);
                 umem->page_shift = huge_page_shift(h);
+                up_read(&mm->mmap_sem);
                 umem->hugetlb = 1;
         } else {
                 umem->hugetlb = 0;