[PATCH 3/4] iommufd: Release current IOAS on xa_store() failure

[Shuai Xue]

iommufd_take_all_iova_rwsem() takes an object reference and the
iova_rwsem write lock before storing the IOAS in the temporary ioas_list
xarray.

If xa_store() fails, the current IOAS has not been inserted into
ioas_list yet. iommufd_release_all_iova_rwsem() only unwinds IOAS
objects already present in that xarray, so it cannot release the current
IOAS.

Release the current IOAS rwsem and object reference before unwinding the
previously stored entries.

Fixes: 051ae5aa73d7 ("iommufd: Lock all IOAS objects")
Cc: stable@xxxxxxxxxxxxxxx
Assisted-by: Qoder:Qwen-3.8-MAX-Preview
Signed-off-by: Shuai Xue <xueshuai@xxxxxxxxxxxxxxxxx>
---
 drivers/iommu/iommufd/ioas.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/iommu/iommufd/ioas.c b/drivers/iommu/iommufd/ioas.c
index fed06c2b728e..28616465ea6a 100644
--- a/drivers/iommu/iommufd/ioas.c
+++ b/drivers/iommu/iommufd/ioas.c
@@ -427,6 +427,8 @@ static int iommufd_take_all_iova_rwsem(struct iommufd_ctx *ictx,
 
 		rc = xa_err(xa_store(ioas_list, index, ioas, GFP_KERNEL));
 		if (rc) {
+			up_write(&ioas->iopt.iova_rwsem);
+			refcount_dec(&ioas->obj.users);
 			iommufd_release_all_iova_rwsem(ictx, ioas_list);
 			return rc;
 		}
-- 
2.39.3