This is a note to let you know that I've just added the patch titled
IB/mlx5: Take write semaphore when changing the vma struct
to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: ib-mlx5-take-write-semaphore-when-changing-the-vma-struct.patch and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From foo@baz Thu Mar 22 14:40:23 CET 2018
From: Maor Gottlieb maorg@mellanox.com Date: Wed, 29 Mar 2017 06:03:02 +0300 Subject: IB/mlx5: Take write semaphore when changing the vma struct
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/infiniband/hw/mlx5/main.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/infiniband/hw/mlx5/main.c +++ b/drivers/infiniband/hw/mlx5/main.c @@ -1313,7 +1313,7 @@ static void mlx5_ib_disassociate_ucontex /* 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_ucontex 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); }
Patches currently in stable-queue which might be from maorg@mellanox.com are
queue-4.9/ib-mlx4-change-vma-from-shared-to-private.patch queue-4.9/ib-mlx5-take-write-semaphore-when-changing-the-vma-struct.patch queue-4.9/ib-mlx5-change-vma-from-shared-to-private.patch queue-4.9/ib-mlx4-take-write-semaphore-when-changing-the-vma-struct.patch