6.4-stable review patch. If anyone has any objections, please let me know.
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From: Jason Gunthorpe jgg@nvidia.com
[ Upstream commit 31422dff187b243c58f3a97d16bbe9e9ada639fe ]
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.co... Reviewed-by: Kevin Tian kevin.tian@intel.com Tested-by: Nicolin Chen nicolinc@nvidia.com Signed-off-by: Jason Gunthorpe jgg@nvidia.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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 ed2937a4e196f..2e43ebf1a2b5c 100644 --- a/drivers/iommu/iommufd/device.c +++ b/drivers/iommu/iommufd/device.c @@ -298,8 +298,8 @@ static int iommufd_device_auto_get_domain(struct iommufd_device *idev, } hwpt->auto_domain = true;
- mutex_unlock(&ioas->mutex); iommufd_object_finalize(idev->ictx, &hwpt->obj); + mutex_unlock(&ioas->mutex); return 0; out_unlock: mutex_unlock(&ioas->mutex);