From 31422dff187b243c58f3a97d16bbe9e9ada639fe Mon Sep 17 00:00:00 2001 From: Jason Gunthorpe Date: Mon, 17 Jul 2023 15:12:07 -0300 Subject: [PATCH] iommufd: Fix locking around hwpt allocation Due to the auto_domains mechanism the ioas->mutex must be held until the hwpt is completely setup by iommufd_object_abort_and_destroy() or iommufd_object_finalize(). This prevents a concurrent iommufd_device_auto_get_domain() from seeing an incompletely initialized object through the ioas->hwpt_list. To make this more consistent move the unlock until after finalize. Fixes: e8d57210035b ("iommufd: Add kAPI toward external drivers for physical devices") Link: https://lore.kernel.org/r/11-v8-6659224517ea+532-iommufd_alloc_jgg@nvidia.com Reviewed-by: Kevin Tian Tested-by: Nicolin Chen Signed-off-by: Jason Gunthorpe --- drivers/iommu/iommufd/device.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c index 08bba99f2fb01..9b9244c5b0ce4 100644 --- a/drivers/iommu/iommufd/device.c +++ b/drivers/iommu/iommufd/device.c @@ -441,8 +441,8 @@ static int iommufd_device_auto_get_domain(struct iommufd_device *idev, hwpt->auto_domain = true; *pt_id = hwpt->obj.id; - mutex_unlock(&ioas->mutex); iommufd_object_finalize(idev->ictx, &hwpt->obj); + mutex_unlock(&ioas->mutex); return 0; out_unlock: mutex_unlock(&ioas->mutex);