[PATCH AUTOSEL for 4.9 067/190] IB/mlx5: Change vma from shared to private

[Sasha Levin]

From: Maor Gottlieb <maorg@xxxxxxxxxxxx>

[ Upstream commit 1377661298d2820d675553d186c31b6f46c140d0 ]

Anonymous VMA (->vm_ops == NULL) cannot be shared, otherwise
it would lead to SIGBUS.

Remove the shared flags from the vma after we change it to be
anonymous.

This is easily reproduced by doing modprobe -r while running a
user-space application such as raw_ethernet_bw.

Fixes: 7c2344c3bbf97 ('IB/mlx5: Implements disassociate_ucontext API')
Signed-off-by: Maor Gottlieb <maorg@xxxxxxxxxxxx>
Signed-off-by: Leon Romanovsky <leon@xxxxxxxxxx>
Signed-off-by: Doug Ledford <dledford@xxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
---
 drivers/infiniband/hw/mlx5/main.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/infiniband/hw/mlx5/main.c b/drivers/infiniband/hw/mlx5/main.c
index 150227786969..d7da1dca765f 100644
--- a/drivers/infiniband/hw/mlx5/main.c
+++ b/drivers/infiniband/hw/mlx5/main.c
@@ -1323,6 +1323,7 @@ static void mlx5_ib_disassociate_ucontext(struct ib_ucontext *ibcontext)
 		/* context going to be destroyed, should
 		 * not access ops any more.
 		 */
+		vma->vm_flags &= ~(VM_SHARED | VM_MAYSHARE);
 		vma->vm_ops = NULL;
 		list_del(&vma_private->list);
 		kfree(vma_private);
-- 
2.14.1