[PATCH 4.14 021/137] RDMA/i40w: Hold read semaphore while looking after VMA

[Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>]

4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Leon Romanovsky <leonro@xxxxxxxxxxxx>

[ Upstream commit 5d9a2b0e28759e319a623da33940dbb3ce952b7d ]

VMA lookup is supposed to be performed while mmap_sem is held.

Fixes: f26c7c83395b ("i40iw: Add 2MB page support")
Signed-off-by: Leon Romanovsky <leonro@xxxxxxxxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/infiniband/hw/i40iw/i40iw_verbs.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/infiniband/hw/i40iw/i40iw_verbs.c
+++ b/drivers/infiniband/hw/i40iw/i40iw_verbs.c
@@ -1408,6 +1408,7 @@ static void i40iw_set_hugetlb_values(u64
 	struct vm_area_struct *vma;
 	struct hstate *h;
 
+	down_read(&current->mm->mmap_sem);
 	vma = find_vma(current->mm, addr);
 	if (vma && is_vm_hugetlb_page(vma)) {
 		h = hstate_vma(vma);
@@ -1416,6 +1417,7 @@ static void i40iw_set_hugetlb_values(u64
 			iwmr->page_msk = huge_page_mask(h);
 		}
 	}
+	up_read(&current->mm->mmap_sem);
 }
 
 /**