From 0dbcdf4473a614adbd732d567c9b39ac0e040e0c Mon Sep 17 00:00:00 2001 From: Shuai Xue Date: Sun, 26 Jul 2026 15:43:30 +0800 Subject: [PATCH] iommufd: Avoid locking internal accesses during unmap iommufd_access_notify_unmap() skips internal accesses because they do not have an external unmap callback to invoke. However, the current test calls iommufd_lock_obj() before checking whether the access is internal. If iommufd_lock_obj() succeeds, the loop then sees the internal access and continues, bypassing the matching iommufd_put_object() used by the normal unmap path. This leaks the object reference taken by iommufd_lock_obj(). Check for internal accesses first so skipped entries are never locked. Fixes: 27b77ea5feaa ("iommufd/access: Bypass access->ops->unmap for internal use") Cc: stable@vger.kernel.org Assisted-by: Qoder:Qwen-3.8-MAX-Preview Signed-off-by: Shuai Xue Reviewed-by: Kevin Tian Reviewed-by: Jason Gunthorpe Signed-off-by: Joerg Roedel --- drivers/iommu/iommufd/device.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c index 170a7005f0bc..e4537db724d5 100644 --- a/drivers/iommu/iommufd/device.c +++ b/drivers/iommu/iommufd/device.c @@ -1307,8 +1307,8 @@ void iommufd_access_notify_unmap(struct io_pagetable *iopt, unsigned long iova, xa_lock(&ioas->iopt.access_list); xa_for_each(&ioas->iopt.access_list, index, access) { - if (!iommufd_lock_obj(&access->obj) || - iommufd_access_is_internal(access)) + if (iommufd_access_is_internal(access) || + !iommufd_lock_obj(&access->obj)) continue; xa_unlock(&ioas->iopt.access_list);