| From | Sasha Levin <> | Subject | [PATCH AUTOSEL for 4.9 066/190] IB/mlx5: Take write semaphore when changing the vma struct | Date | Thu, 8 Mar 2018 04:59:21 +0000 |
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From: Maor Gottlieb <maorg@mellanox.com>
[ Upstream commit ecc7d83be3243835c9396a1a2fb8ce95f205207b ]
When the driver disassociate user context, it changes the vma to anonymous by setting the vm_ops to null and zap the vma ptes.
In order to avoid race in the kernel, we need to take write lock before we change the vma entries.
Fixes: 7c2344c3bbf97 ('IB/mlx5: Implements disassociate_ucontext API') Signed-off-by: Maor Gottlieb <maorg@mellanox.com> Signed-off-by: Leon Romanovsky <leon@kernel.org> Signed-off-by: Doug Ledford <dledford@redhat.com> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> --- drivers/infiniband/hw/mlx5/main.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/infiniband/hw/mlx5/main.c b/drivers/infiniband/hw/mlx5/main.c index 5e29fbd3a5a0..150227786969 100644 --- a/drivers/infiniband/hw/mlx5/main.c +++ b/drivers/infiniband/hw/mlx5/main.c @@ -1313,7 +1313,7 @@ static void mlx5_ib_disassociate_ucontext(struct ib_ucontext *ibcontext) /* need to protect from a race on closing the vma as part of * mlx5_ib_vma_close. */ - down_read(&owning_mm->mmap_sem); + down_write(&owning_mm->mmap_sem); list_for_each_entry_safe(vma_private, n, &context->vma_private_list, list) { vma = vma_private->vma; @@ -1327,7 +1327,7 @@ static void mlx5_ib_disassociate_ucontext(struct ib_ucontext *ibcontext) list_del(&vma_private->list); kfree(vma_private); } - up_read(&owning_mm->mmap_sem); + up_write(&owning_mm->mmap_sem); mmput(owning_mm); put_task_struct(owning_process); } -- 2.14.1
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