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Commit 9238066e authored by Maor Gottlieb's avatar Maor Gottlieb Committed by Greg Kroah-Hartman
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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: 7c2344c3 ('IB/mlx5: Implements disassociate_ucontext API')
Signed-off-by: default avatarMaor Gottlieb <maorg@mellanox.com>
Signed-off-by: default avatarLeon Romanovsky <leon@kernel.org>
Signed-off-by: default avatarDoug Ledford <dledford@redhat.com>
Signed-off-by: default avatarSasha Levin <alexander.levin@microsoft.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent df7aedb1

drivers/infiniband/hw/mlx5/main.c

+2 −2
Original line number Diff line number Diff line
@@ -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);

}