From d769711fcddd005f1e654b3bde547140917fe696 Mon Sep 17 00:00:00 2001 From: Nicolin Chen Date: Fri, 24 Apr 2026 18:15:20 -0700 Subject: [PATCH] iommu: Fix NULL group->domain dereference in pci_dev_reset_iommu_done() Local sashiko review pointed it out that group->domain could be NULL when a default domain fails to allocate during the first probe, which can crash at domain->ops->attach_dev dereference in __iommu_attach_device() invoked by pci_dev_reset_iommu_done(). pci_dev_reset_iommu_prepare() is fine as an old_domain pointer can be NULL. Skip the re-attach in pci_dev_reset_iommu_done() to fix the bug. Fixes: c279e83953d9 ("iommu: Introduce pci_dev_reset_iommu_prepare/done()") Cc: stable@vger.kernel.org Signed-off-by: Nicolin Chen Reviewed-by: Lu Baolu Signed-off-by: Joerg Roedel --- drivers/iommu/iommu.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 61c12ba78206..b8847cc43e76 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -4073,8 +4073,13 @@ void pci_dev_reset_iommu_done(struct pci_dev *pdev) if (WARN_ON(!group->blocking_domain)) return; - /* Re-attach RID domain back to group->domain */ - if (group->domain != group->blocking_domain) { + /* + * Re-attach RID domain back to group->domain + * + * Leave the device parked in the blocking_domain if group->domain isn't + * initialized yet + */ + if (group->domain && group->domain != group->blocking_domain) { WARN_ON(__iommu_attach_device(group->domain, &pdev->dev, group->blocking_domain)); }