From 9238066e2838e2981c908e66bfc599442fd6917b Mon Sep 17 00:00:00 2001 From: Maor Gottlieb Date: Wed, 29 Mar 2017 06:03:02 +0300 Subject: [PATCH] IB/mlx5: Take write semaphore when changing the vma struct [ 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 Signed-off-by: Leon Romanovsky Signed-off-by: Doug Ledford Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- 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 5e29fbd..1502277 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); } -- 2.7.4