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From: Jason Gunthorpe <jgg@nvidia.com>
To: iommu@lists.linux.dev, linux-kselftest@vger.kernel.org
Cc: Lu Baolu <baolu.lu@linux.intel.com>,
	Kevin Tian <kevin.tian@intel.com>,
	kvm@vger.kernel.org, Lixiao Yang <lixiao.yang@intel.com>,
	Matthew Rosato <mjrosato@linux.ibm.com>,
	Nicolin Chen <nicolinc@nvidia.com>, Yi Liu <yi.l.liu@intel.com>
Subject: [PATCH v6 11/19] iommufd: Fix locking around hwpt allocation
Date: Thu, 20 Apr 2023 15:51:26 -0300	[thread overview]
Message-ID: <11-v6-fdb604df649a+369-iommufd_alloc_jgg@nvidia.com> (raw)
In-Reply-To: <0-v6-fdb604df649a+369-iommufd_alloc_jgg@nvidia.com>

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")
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---
 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 782b4fd76f31eb..2155fafda27a5f 100644
--- a/drivers/iommu/iommufd/device.c
+++ b/drivers/iommu/iommufd/device.c
@@ -398,8 +398,8 @@ 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);
-- 
2.40.0


  parent reply	other threads:[~2023-04-20 18:53 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-04-20 18:51 [PATCH v6 00/19] Add iommufd physical device operations for replace and alloc hwpt Jason Gunthorpe
2023-04-20 18:51 ` [PATCH v6 01/19] iommufd: Move isolated msi enforcement to iommufd_device_bind() Jason Gunthorpe
2023-04-20 18:51 ` [PATCH v6 02/19] iommufd: Add iommufd_group Jason Gunthorpe
2023-04-20 18:51 ` [PATCH v6 03/19] iommufd: Replace the hwpt->devices list with iommufd_group Jason Gunthorpe
2023-04-20 18:51 ` [PATCH v6 04/19] iommu: Export iommu_get_resv_regions() Jason Gunthorpe
2023-04-20 18:51 ` [PATCH v6 05/19] iommufd: Keep track of each device's reserved regions instead of groups Jason Gunthorpe
2023-04-20 18:51 ` [PATCH v6 06/19] iommufd: Use the iommufd_group to avoid duplicate MSI setup Jason Gunthorpe
2023-04-20 18:51 ` [PATCH v6 07/19] iommufd: Make sw_msi_start a group global Jason Gunthorpe
2023-04-20 18:51 ` [PATCH v6 08/19] iommufd: Move putting a hwpt to a helper function Jason Gunthorpe
2023-04-20 18:51 ` [PATCH v6 09/19] iommufd: Add enforced_cache_coherency to iommufd_hw_pagetable_alloc() Jason Gunthorpe
2023-04-20 18:51 ` [PATCH v6 10/19] iommufd: Allow a hwpt to be aborted after allocation Jason Gunthorpe
2023-04-21  7:29   ` Tian, Kevin
2023-04-20 18:51 ` Jason Gunthorpe [this message]
2023-04-21  7:30   ` [PATCH v6 11/19] iommufd: Fix locking around hwpt allocation Tian, Kevin
2023-04-20 18:51 ` [PATCH v6 12/19] iommufd: Reorganize iommufd_device_attach into iommufd_device_change_pt Jason Gunthorpe
2023-04-20 18:51 ` [PATCH v6 13/19] iommu: Introduce a new iommu_group_replace_domain() API Jason Gunthorpe
2023-04-20 18:51 ` [PATCH v6 14/19] iommufd: Add iommufd_device_replace() Jason Gunthorpe
2023-04-20 18:51 ` [PATCH v6 15/19] iommufd: Make destroy_rwsem use a lock class per object type Jason Gunthorpe
2023-04-20 18:51 ` [PATCH v6 16/19] iommufd/selftest: Test iommufd_device_replace() Jason Gunthorpe
2023-04-20 18:51 ` [PATCH v6 17/19] iommufd: Add IOMMU_HWPT_ALLOC Jason Gunthorpe
2023-04-20 18:51 ` [PATCH v6 18/19] iommufd/selftest: Return the real idev id from selftest mock_domain Jason Gunthorpe
2023-04-20 18:51 ` [PATCH v6 19/19] iommufd/selftest: Add a selftest for IOMMU_HWPT_ALLOC Jason Gunthorpe
2023-04-21  1:35 ` [PATCH v6 00/19] Add iommufd physical device operations for replace and alloc hwpt Nicolin Chen

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