diff options
| author | Jean-Christophe Guillain <jean-christophe@guillain.net> | 2026-11-05 16:32:19 +0000 |
|---|---|---|
| committer | Joerg Roedel <joerg.roedel@amd.com> | 2026-11-06 13:22:44 +0100 |
| commit | 2cf4be57b301ed2d7af82e70cff5dfd96894d8de (patch) | |
| tree | 840554440aef942334f2800bf8a5ebe2347e7364 | |
| parent | fa77b023eb80cdb297ff32f6b13786e483a81ca8 (diff) | |
iommu/amd: Fix NULL pointer dereference for GPUs without upstream bridge
pci_upstream_bridge() can return NULL for devices without an upstream
bridge. The AMD GPU identity mapping quirk dereferences the returned
pointer unconditionally, causing a kernel panic during boot.
Check the pointer before accessing the bridge vendor ID.
This fixes a boot regression on a Lenovo system with an AMD PRO
A10-9700E APU. The system now boots with AMD IOMMU enabled.
Fixes: bf5bdfd1f8d4 ("iommu/amd: Force identity mode for selected GPUs only")
Signed-off-by: Jean-Christophe Guillain <jean-christophe@guillain.net>
Signed-off-by: Vasant Hegde <vasant.hegde@amd.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
| -rw-r--r-- | drivers/iommu/amd/iommu.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c index 91981c8a9614..41ee4ad1dcf8 100644 --- a/drivers/iommu/amd/iommu.c +++ b/drivers/iommu/amd/iommu.c @@ -3191,6 +3191,7 @@ static bool amd_iommu_is_attach_deferred(struct device *dev) static bool quirks_force_identity_mapping(struct pci_dev *pdev) { + struct pci_dev *bridge; int class = pdev->class >> 8; /* AMD GPU vendor ID */ @@ -3202,7 +3203,8 @@ static bool quirks_force_identity_mapping(struct pci_dev *pdev) class != PCI_CLASS_DISPLAY_OTHER) return false; - if (pci_upstream_bridge(pdev)->vendor == PCI_VENDOR_ID_ATI) + bridge = pci_upstream_bridge(pdev); + if (bridge && bridge->vendor == PCI_VENDOR_ID_ATI) return false; /* It is the GPU in an APU, force identity domain */ |