Commit ecc7d83b authored by Maor Gottlieb's avatar Maor Gottlieb Committed by Doug Ledford

IB/mlx5: Take write semaphore when changing the vma struct

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>
parent ca37a664
...@@ -1478,7 +1478,7 @@ static void mlx5_ib_disassociate_ucontext(struct ib_ucontext *ibcontext) ...@@ -1478,7 +1478,7 @@ static void mlx5_ib_disassociate_ucontext(struct ib_ucontext *ibcontext)
/* need to protect from a race on closing the vma as part of /* need to protect from a race on closing the vma as part of
* mlx5_ib_vma_close. * 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_for_each_entry_safe(vma_private, n, &context->vma_private_list,
list) { list) {
vma = vma_private->vma; vma = vma_private->vma;
...@@ -1492,7 +1492,7 @@ static void mlx5_ib_disassociate_ucontext(struct ib_ucontext *ibcontext) ...@@ -1492,7 +1492,7 @@ static void mlx5_ib_disassociate_ucontext(struct ib_ucontext *ibcontext)
list_del(&vma_private->list); list_del(&vma_private->list);
kfree(vma_private); kfree(vma_private);
} }
up_read(&owning_mm->mmap_sem); up_write(&owning_mm->mmap_sem);
mmput(owning_mm); mmput(owning_mm);
put_task_struct(owning_process); put_task_struct(owning_process);
} }
......
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