It is possible for archdata.iommu to be set to DEFER_DEVICE_DOMAIN_INFO or DUMMY_DEVICE_DOMAIN_INFO so check for those values before calling __dmar_remove_one_dev_info. Without a check it can result in a null pointer dereference. This has been seen while booting a kdump kernel on an HP dl380 gen9.

Cc: Joerg Roedel joro@8bytes.org Cc: Lu Baolu baolu.lu@linux.intel.com Cc: David Woodhouse dwmw2@infradead.org Cc: stable@vger.kernel.org # 5.3+ Cc: linux-kernel@vger.kernel.org Fixes: ae23bfb68f28 ("iommu/vt-d: Detach domain before using a private one") Signed-off-by: Jerry Snitselaar jsnitsel@redhat.com --- drivers/iommu/intel-iommu.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index 1801f0aaf013..932267f49f9a 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -5163,7 +5163,8 @@ static void dmar_remove_one_dev_info(struct device *dev)

spin_lock_irqsave(&device_domain_lock, flags); info = dev->archdata.iommu; - if (info) + if (info && info != DEFER_DEVICE_DOMAIN_INFO + && info != DUMMY_DEVICE_DOMAIN_INFO) __dmar_remove_one_dev_info(info); spin_unlock_irqrestore(&device_domain_lock, flags); }